Respiratory Tract Disorders and Diseases Lecture Notes PDF

**RESPIRATORY SYSTEM AND ENVIRONMENTAL PHYSIOLOGY.** **INTRODUCTION** The first breath takes place only after birth. Foetal lungs are non-functional. So, during intrauterine life, the exchange of gases between foetal blood and mother's blood occurs through the placenta. After the first breath, the respiratory process continues throughout the life. Permanent stoppage of respiration occurs only at death. Respiration is the process by which oxygen is taken in and carbon dioxide is given out. The major function of the respiratory system is to supply the body with oxygen and dispose of carbon dioxide. To accomplish this function, at least four processes collectively called respiration must happen: 1. **Pulmonary ventilation:** movement of air into and out of the lungs so that the gases there are continuously changed and refreshed (commonly called breathing). It consists of two phases: **i) inspiration:** the period when air flows into the lungs. **ii) expiration:** the period when gases exit the lungs. 2. **External respiration:** movement of oxygen from the lungs to the blood and of carbon dioxide from the blood to the lungs. 3. **Transport of respiratory gases:** transport of oxygen from the lungs to the tissue cells of the body, and of carbon dioxide from the tissue cells to the lungs. This transport is accomplished by the cardiovascular system using blood as the transport fluid. 4. **Internal respiration:** movement of oxygen from the blood to the tissue cells and of carbon dioxide from tissue cells to the blood. **Cellular respiration:** is the cornerstone of all energy-producing chemical reactions in the body. This is where the actual use of oxygen and the production of carbon dioxide by the tissue cells take place. **PARTS OF THE RESPIRATORY SYSTEM** 1. Nose. 2. Paranasal Sinuses. 3. Pharynx 4. Larynx. 5. Tracheal. 6. Bronchi. 7. Lungs. 8. Alveoli. Functionally the system consists of two zones: - **The respiratory zone** the actual site of gas exchange, is composed of the respiratory bronchioles, alveolar ducts, and alveoli, all microscopic structures. - **The conducting zone:** includes all the respiratory pathways, which provide rigid conduits for air to reach the gas exchange sites. this zone also cleanses, humidifies, and warms incoming air so that air reaching the cells. +-----------------+-----------------+-----------------+-----------------+ | **S/NO** | **STRUCTURE** | **DESCRIPTION | **FUNCTION** | | | | GENERAL AND | | | | | DISTINCTIVE | | | | | FEATURES** | | +=================+=================+=================+=================+ | 1. | Nose | The jutting | Produces mucus, | | | | external | filters, warms, | | | | portion is | and moistens | | | | supported by | incoming air, | | | | bone and | resonance | | | | cartilage. The | chamber for | | | | internal nasal | speech. | | | | cavity is | | | | | divided by | Receptors for | | | | middle nasal | sense of smell. | | | | septum and | | | | | lined with | | | | | mucosa. | | | | | | | | | | The roof of the | | | | | nasal cavity | | | | | contains | | | | | olfactory | | | | | epithelium | | +-----------------+-----------------+-----------------+-----------------+ | 2. | Paranasal | Mucosa-lined, | Same as the | | | sinuses | air-filled | nasal cavity, | | | | cavities in | also lighten | | | | cranial bones | the skull. | | | | surrounding the | | | | | nasal cavity. | | +-----------------+-----------------+-----------------+-----------------+ | 3 | Pharynx | The passageway | Passage of | | | | connecting the | airway and | | | | nasal cavity to | food. | | | | the larynx and | | | | | oral cavity to | Facilitates | | | | oesophagus. | exposure of | | | | | immune system | | | | Three | to inhaled | | | | subdivisions: | antigens | | | | nasopharynx, | | | | | oropharynx and | | | | | laryngopharynx. | | | | | | | | | | Houses tonsils | | | | | (lymphoid | | | | | tissue masses | | | | | involve in | | | | | protecting | | | | | against | | | | | pathogens) | | +-----------------+-----------------+-----------------+-----------------+ | 4 | Larynx | Connects | Air passageway; | | | | pharynx to | prevents food | | | | trachea. Has | from entering | | | | framework of | the lower | | | | cartilage and | respiratory | | | | dense | tract. | | | | connective | | | | | tissue. Opening | Voice | | | | (glottis) can | production. | | | | be closed by | | | | | epiglottis or | | | | | vocal folds. | | | | | | | | | | House vocal | | | | | folds (true | | | | | vocal cords) | | +-----------------+-----------------+-----------------+-----------------+ | 5 | Trachea | Flexible tube | Air passageway | | | | running from | connecting | | | | larynx and | trachea with | | | | dividing | alveoli; | | | | inferiorly into | cleans, warms, | | | | two main | and moistens | | | | bronchi. | incoming air | | | | | | | | | Walls contain | | | | | C-shaped | | | | | cartilages that | | | | | are incomplete | | | | | posteriorly | | | | | were connected | | | | | by trachealis | | | | | muscle. | | +-----------------+-----------------+-----------------+-----------------+ | 6 | Bronchial tree | Consists of | Air passageway | | | | right and left | cleans, warms, | | | | main bronchi, | and moistens | | | | which subdivide | incoming air | | | | within the | | | | | lungs to form | | | | | two and | | | | | segmental | | | | | bronchi and | | | | | bronchioles. | | | | | Bronchiolar | | | | | walls lack | | | | | cartilage but | | | | | contain | | | | | complete layer | | | | | of smooth | | | | | muscle. | | | | | Constriction of | | | | | this muscle | | | | | impedes | | | | | expiration. | | +-----------------+-----------------+-----------------+-----------------+ | 7 | Alveoli | Microscopic | Main sites of | | | | chambers at the | gas exchange. | | | | termini of | | | | | bronchial tree. | Reduces surface | | | | Walls of simple | tension, helps | | | | squamous | prevent lung | | | | epithelium are | collapse. | | | | underlain by | | | | | thin basement | | | | | membrane. | | | | | External | | | | | surface is | | | | | intimately | | | | | associated with | | | | | pulmonary | | | | | capillaries. | | | | | | | | | | Special | | | | | alveolar cells | | | | | produce | | | | | surfactant. | | +-----------------+-----------------+-----------------+-----------------+ | 8 | Lungs | Paired | House | | | | composite | respiratory | | | | organs that | passages | | | | flank | smaller than | | | | mediastinum in | the main | | | | thorax. | bronchi. | | | | Composed | | | | | primarily of | | | | | alveoli and | | | | | respiratory | | | | | passageways. | | | | | Stroma is | | | | | fibrous elastic | | | | | connective | | | | | tissue, | | | | | allowing lungs | | | | | to recoil | | | | | passively | | | | | during | | | | | expiration | | +-----------------+-----------------+-----------------+-----------------+ | 9 | Pleurae | Serous | Produces | | | | membrane. | lubricating | | | | Parietal pleura | fluid and | | | | lines thoracic; | compartmentaliz | | | | visceral pleura | e | | | | covers external | lungs | | | | lung surfaces. | | +-----------------+-----------------+-----------------+-----------------+ **MECHANISM OF BREAATHING** (**PHYSIOLOGY OF VENTILATION)** The processes of inspiration (breathing in) and expiration (breathing out) are vital for providing oxygen to tissues and removing carbon dioxide from the body. Inspiration occurs via active contraction of muscles -- such as the diaphragm -- whereas expiration tends to be passive unless it is forced. We shall look at the-- the process of inspiration and expiration, how this differs between quiet and forced breathing, and their clinical correlations. **1. THE LUNGS AND BREATHING** The space between the outer surface of the lungs and inner thoracic wall is known as the pleural space. This is usually filled with pleural fluid, forming a seal which holds the lungs against the thoracic wall by the force of surface tension. This seal ensures that when the thoracic cavity expands or reduces, the lungs undergo expansion or reduction in size accordingly. During breathing, the contraction and relaxation of muscles acts to change the volume of the thoracic cavity. As the thoracic cavity and lungs move together, this changes the volume of the lungs, in turn changing the pressure inside the lungs. Boyle's law states that the volume of gas is inversely proportional to pressure (when temperature is constant). Therefore: When the volume of the thoracic cavity increases -- the volume of the lungs increases and the pressure within the lungs decreases. When the volume of the thoracic cavity decreases -- the volume of the lungs decreases and the pressure within the lungs increases. **2. PROCESS OF INSPIRATION** Inspiration is the phase of ventilation in which air enters the lungs. It is initiated by contraction of the inspiratory muscles: Diaphragm -- flattens, extending the superior/inferior dimension of the thoracic cavity. External intercostal muscles -- elevate the ribs and sternum, extending the anterior/posterior dimension of the thoracic cavity. The action of the inspiratory muscles results in an increase in the volume of the thoracic cavity. As the lungs are held against the inner thoracic wall by the pleural seal, they also undergo an increase in volume. As per Boyle's law, an increase in lung volume results in a decrease in the pressure within the lungs. The pressure of the environment external to the lungs is now greater than the environment within the lungs, meaning air moves into the lungs down the pressure gradient. ![](media/image2.png) **Inhalation Exhalation** **3. PROCESS OF PASSIVE EXPIRATION** Expiration is the phase of ventilation in which air is expelled from the lungs. It is initiated by the relaxation of the inspiratory muscles: Diaphragm -- relaxes to return to its resting position, reducing the superior/inferior dimension of the thoracic cavity. External intercostal muscles -- relax to depress the ribs and sternum, reducing the anterior/posterior dimension of the thoracic cavity. The relaxation of the inspiratory muscles results in a decrease in the volume of the thoracic cavity. The elastic recoil of the previously expanded lung tissue allows them to return to their original size. As per Boyle's law, a decrease in lung volume results in an increase in the pressure within the lungs. The pressure inside the lungs is now greater than in the external environment, meaning air moves out of the lungs down the pressure gradient. **Forced Breathing** Forced breathing is an active mode of breathing which utilises additional muscles to rapidly expand and contract the thoracic cavity volume. It most commonly occurs during exercise. **Active Inspiration** Active inspiration involves the contraction of the accessory muscles of breathing (in addition to those of quiet inspiration, the diaphragm and external intercostals). All these muscles act to increase the volume of the thoracic cavity: Scalene -- elevates the upper ribs. Sternocleidomastoid -- elevates the sternum. Pectoralis major and minor -- pulls ribs outwards. Serratus anterior -- elevates the ribs (when the scapulae are fixed). Latissimus dorsi -- elevates the lower ribs. **Active Expiration** Active expiration utilises the contraction of several thoracic and abdominal muscles. These muscles act to decrease the volume of the thoracic cavity: Anterolateral abdominal wall -- increases the intra-abdominal pressure, pushing the diaphragm further upwards into the thoracic cavity. Internal intercostal -- depresses the ribs. Innermost intercostal -- depresses the ribs. **4. MOVEMENTS OF THORACIC CAGE** Inspiration causes enlargement of thoracic cage. Thoracic cage enlarges because of increase in all diameters, viz. anteroposterior, transverse, and vertical diameters. Anteroposterior and transverse diameters of thoracic cage are increased by the elevation of ribs. Vertical diameter is increased by the descent of diaphragm. In general, change in the size of thoracic cavity occurs because of the movements of four units of structures: 1\. Thoracic lid 2\. Upper costal series 3\. Lower costal series 4\. Diaphragm. **1. Thoracic Lid** Thoracic lid is formed by manubrium sterni and the first pair of ribs. It is also called thoracic operculum. Movement of thoracic lid increases the anteroposterior diameter of thoracic cage. Due to the contraction of scalene muscles, the first ribs move upwards to a more horizontal position. This increases the anteroposterior diameter of upper thoracic cage. **2. Upper Costal Series** Upper costal series is constituted by second to sixth pair of ribs. Movement of upper costal series increases the anteroposterior and transverse diameter of the thoracic cage. Movement of upper costal series is of two types: i\. Pump handle movement ii\. Bucket handle movement. Pump handle movement Contraction of external intercostal muscles causes elevation of these ribs and upward and forward movement of sternum. This movement is called pump handle movement. It increases anteroposterior diameter of the thoracic cage. Bucket handle movement Simultaneously, the central portions of these ribs (arches of ribs) move upwards and outwards to a more horizontal position. This movement is called bucket handle movement and it increases the transverse diameter of thoracic cage. **3. Lower Costal Series** Lower costal series includes seventh to tenth pair of ribs. Movement of lower costal series increases the transverse diameter of thoracic cage by bucket handle movement. Bucket handle movement Lower costal series of ribs also show bucket handle movement by swinging outward and upward. This movement increases the transverse diameter of the thoracic cage. Eleventh and twelfth pairs of ribs are the floating ribs. These ribs are not involved in changing the size of thoracic cage. **4. Diaphragm** Movement of diaphragm increases the vertical diameter of thoracic cage. Normally, before inspiration the diaphragm is dome shaped with convexity facing upwards. During inspiration, due to the contraction, muscle fibres are shortened. But the central tendinous portion is drawn downwards so the diaphragm is flattened. Flattening of diaphragm increases the vertical diameter of the thoracic cage. **5. MOVEMENTS OF LUNGS** During inspiration, due to the enlargement of thoracic cage, the negative pressure is increased in the thoracic cavity. It causes expansion of the lungs. During expiration, the thoracic cavity decreases in size to the pre-inspiratory position. Pressure in the thoracic cage also comes back to the pre-inspiratory level. It compresses the lung tissues so that, the air is expelled out of lungs. **NORMAL RESPIRATORY RATE AT DIFFERENT AGE** Newborn: 30 to 60/minute Early childhood: 20 to 40/minute Late childhood 15 to 25/minute Adult: 12 to 16/minute. **TYPES OF LUNG FUNCTION TESTS** Lung function tests are of two types: 1\. Static lung function tests 2\. Dynamic lung function tests. **Static Lung Function Tests** Static lung function tests are based on volume of air that flows into or out of lungs. These tests do not depend upon the rate at which air flows. Static lung function tests include static lung volumes and static lung capacities. **Dynamic Lung Function Tests** Dynamic lung function tests are based on time, i.e., the rate at which air flows into or out of lungs. These tests include forced vital capacity, forced expiratory volume, maximum ventilation volume and peak expiratory flow. Dynamic lung function tests are useful in determining the severity of obstructive and restrictive lung diseases. **LUNG VOLUMES** Static lung volumes are the volumes of air breathed by an individual. Each of these volumes represents the volume of air present in the lung under a specified static condition (specific position of thorax). Static lung volumes are of four types: 1. Tidal volume 2. Inspiratory reserve volume 3. Expiratory reserve volume 4. Residual volume 1. **Tidal Volume** Tidal volume (TV) is the volume of air breathed in and out of lungs in a single normal quiet respiration. Tidal volume signifies the normal depth of breathing. Normal Val: 500 mL (0.5 L). 2. **Inspiratory Reserve Volume** Inspiratory reserve volume (IRV) is an additional volume of air that can be inspired forcefully after the end of normal inspiration. Normal Value: 3,300 mL (3.3 L). 3. **Expiratory Reserve Volume** Expiratory reserve volume (EVR) is the additional volume of air that can be expired out forcefully, after normal expiration. Normal Value: 1,000 mL (1 L). 4. **Residual Volume** Residual volume (RV) is the volume of air remaining in lungs even after forced expiration. Normally, lungs cannot be emptied completely even by forceful expiration. Some quantity of air always remains in the lungs even after the forced expiration. Residual volume is significant because of two reasons: 1\. It helps to aerate the blood in between breathing and during expiration 2\. It maintains the contour of the lungs. Normal Value: 1,200 mL (1.2 L) **LUNG CAPACITIES** Static lung capacities are the combination of two or more lung volumes. Static lung capacities are of four types: 1\. Inspiratory capacity 2\. Vital capacity 3\. Functional residual capacity 4\. Total lung capacity. **Inspiratory Capacity** Inspiratory capacity (IC) is the maximum volume of air that is inspired after normal expiration (end expiratory position). It includes tidal volume and inspiratory reserve volume. IC = TV + IRV= 500 + 3,300 = 3,800 mL **VITAL CAPACITY (VC)** Vital capacity (VC) is the maximum volume of air that can be expelled out forcefully after a deep (maximal) inspiration. VC includes inspiratory reserve volume, tidal volume, and expiratory reserve volume. **RESPIRATORY TRACT DISORDERS AND DISEASES** **INTRODUCTION** Respiratory disorders are lung diseases, which are diseases or disorders that can affect respiratory function, the ability to breathe, and how well the lungs work. Lung disease is the third-leading cause of death in the U.S., lung disease, and other breathing problems are leading causes of death in infants. This organ plays a vital role in exchanging gas flow in the human body: the trachea (windpipe), lungs, diaphragms, etc. All these functions together in a proper order to create uninterrupted airflow within the body. When people have respiratory disorders, their tissues, and organs, which exchange oxygen and carbon dioxide, do not work properly. It decreases the oxygen saturation level (SpO2). As a result, people who have been afflicted experience anxiousness, dizziness, disorientation, and bewilderment. These conditions include: - Influenza (the flu) - Asthma - Pneumonia - Acute Bronchitis - Chronic obstructive pulmonary disease (COPD) Chronic bronchitis and Emphysema. - Bronchiectasis - Pulmonary fibrosis - Sarcoidosis - Lung cancer - Pulmonary oedema - Cystic fibrosis - Mesothelioma - Pulmonary hypertension - Tuberculosis **GENERAL SIGNS AND SYMPTOMS OF RESPIRATORY** **DISORDERS AND DISEASES** Symptoms of respiratory disorders vary depending on the condition and may include: - Cough - Shortness of breath - Breathing difficulties - Excess phlegm, mucus, or sputum production - Wheezing - Chest tightness/soreness - Sharp chest pain that is worse when you take a breath. - Difficulty inhaling deeply. - Frequent bronchitis or other lung infections - Fever - Fatigue - Weakness - Weight loss - Loss of appetite - Cold or flu symptoms - Stuffy nose - Sore throat - Headache - Body aches - Swollen lymph nodes **GENERAL TREATMENT FOR RESPIRATORY DISORDERS** **AND DISEASES** Treatment for respiratory disorders varies depending on the condition. - Quick-relief medications bronchodilators (Long-term asthma control medications) - Biologics - Oral corticosteroids - Immunotherapy, useful when asthma is triggered by an allergy. - Chronic obstructive pulmonary disease (COPD) - Quitting smoking - Avoiding second-hand tobacco smoke - Avoiding air pollutants at home and at work - Pulmonary rehabilitation - Medications to treat symptoms. - Supplemental oxygen - Bronchiectasis - Antibiotics - Bronchodilators - Corticosteroids - Chest physiotherapy - Pulmonary rehabilitation - Dietary supplementation - Oxygen (reserved for hypoxemic patients with severe disease) - Hospitalization for severe exacerbations - Surgical therapies - Bronchitis/Acute bronchitis - Home remedies - Rest - Drinking plenty of liquids - Sucking on lozenges, cough drops, or hard candy - Over the counter (OTC) cough and cold medicines and pain-relievers - Inhaling warm, moist air - Don't smoke and avoid second-hand smoke. - Chronic bronchitis - Prescription inhalers or steroids - Oxygen - Pulmonary rehabilitation - Pulmonary fibrosis - Supplemental oxygen - Pulmonary rehabilitation - Medications - Lung transplantation - Sarcoidosis - Mild cases may not need treatment. - Nonsteroidal anti-inflammatory drugs (NSAIDs) - Corticosteroids - Other medications - Rehabilitation programs - Oxygen therapy and/or lung transplantation in severe cases - Lung cancer - Surgery - Photodynamic therapy (PDT) - Laser therapy - Radiation therapy - Radiofrequency ablation (RFA) - Lymph node removal - Chemotherapy - Targeted therapy - Immunotherapy - Participation in clinical trials - Pneumonia - Antibiotics, if the cause is bacterial. - Antivirals, if the cause is viral. - Home treatment such as: - Getting a lot of rest - Drinking plenty of fluids - Fever reducers - Inhaling steam - Don't smoke and avoid second-hand smoke or any other lung irritants. - Pulmonary oedema - Oxygen - Ventilator - Medications such as diuretics and other medicines that strengthen the heart muscle, control the heartbeat, or relieve pressure on the heart. - Influenza - Home remedies - Antiviral medications - Cystic fibrosis - Antibiotics to help prevent or treat infections. - Bronchodilators to help open the airways in the lungs. - Mucus thinners to help thin the mucus in the lungs. - CTFR modulators that improve the function of the faulty CFTR protein. - Airway clearance therapy (chest physiotherapy) - Lung transplant - Mesothelioma - Surgery - Palliative procedures - Radiation therapy - Chemotherapy - Immunotherapy - Targeted therapy - Pulmonary hypertension - Supportive treatments - Oxygen therapy - Diuretics - Digoxin - Exercise - Anticoagulants - Vasodilatory therapies (used to help widen the blood vessels) - Balloon atrial septostomy - Lung transplantation (for severe cases) - Tuberculosis - There are several different drug regimens that must be taken for several months and may include rifampicin, isoniazid plus rifampicin, isoniazid plus rifapentine. - Avoiding alcohol and acetaminophen (Tylenol) **INFLUENZA** Influenza, commonly known as \"the flu\", common cold, rhinitis or grippe, is an acute viral infection of the nasal mucosa, upper or lower respiratory tract and is an infectious disease caused by influenza viruses. Flu (influenza) is an infection of the nose, throat, and lungs, which are part of the respiratory system. Influenza is commonly called the flu, but it\'s not the same as stomach \"flu\" viruses that cause diarrhoea and vomiting. **MODE OF TRANSMISSION** Through breathing, talking, coughing, and sneezing, (which spread respiratory droplets and aerosols that contain virus particles into the air). Respiratory droplets are relatively large and travel less than two meters before falling onto nearby surfaces. As the virus particles gain entrance to the body, they selectively attack and destroy the ciliated epithelial cells that line the upper respiratory tract, bronchial tubes, and trachea. A person susceptible to infection can then contract influenza by encountering these particles. Transmission through contact with a person (person to person), bodily fluids, or intermediate objects (fomites) can also occur, such as through contaminated hands and surfaces as the viruses can survive for hours on non-porous surfaces. The flu may affect individuals of all ages, though the highest incidence of the disease is among children and young adults. Influenza is generally more frequent during the colder months of the year. The **incubation period** of the disease is one to two days, after which the onset of symptoms is abrupt, with sudden and distinct chills, fatigue, and muscle aches. The temperature rises rapidly to 38--40 °C (101--104 °F). A diffuse headache and severe muscular aches throughout the body are experienced, often accompanied by irritation or a sense of rawness in the throat. In three to four days the temperature begins to fall, and the person begins to recover. Symptoms associated with respiratory tract infection, such as coughing and nasal discharge, become more prominent and may be accompanied by lingering feelings of weakness. Death may occur, usually among older people already weakened by other debilitating disorders and is caused in most of those cases by complications such as pneumonia or bronchitis. **PATHOPHYSIOLOGY OF INFLUENZA** In humans, influenza viruses first cause infection by infecting epithelial cells in the respiratory tract. Illness during infection is primarily the result of lung inflammation and compromise caused by epithelial cell infection and death, combined with inflammation caused by the immune system\'s response to infection. Non-respiratory organs can become involved, but the mechanisms by which influenza is involved in these cases are unknown. Severe respiratory illness can be caused by multiple, non-exclusive mechanisms, including obstruction of the airways, loss of alveolar structure, loss of lung epithelial integrity due to epithelial cell infection and death, and degradation of the extracellular matrix that maintains lung structure. Alveolar cell infection appears to drive severe symptoms since this results in impaired gas exchange and enables viruses to infect endothelial cells, which produce large quantities of pro-inflammatory cytokines. The pathophysiology of influenza is significantly influenced by which receptors influenza viruses bind to during entry into cells. Influenza, commonly known as the flu, is a highly contagious viral respiratory illness caused by influenza viruses. The pathophysiology of influenza involves several key processes: **1. Viral Entry** Influenza viruses primarily enter the body through inhalation of respiratory droplets containing the virus. The viruses can also spread through direct contact with contaminated surfaces or through aerosolized droplets generated by coughing or sneezing. **2. Attachment and Invasion** Influenza viruses attach to and invade the epithelial cells that line the respiratory tract, particularly the upper and lower airways. The viral particles bind to specific receptors on the surface of respiratory epithelial cells, allowing entry into the cells. **3. Viral Replication** Once inside the host cells, the influenza viruses replicate rapidly, utilizing the host\'s cellular machinery. Viral replication leads to the production of new viral particles, which are released from infected cells and can infect neighbouring cells. **4. Inflammatory Response** The invasion of respiratory epithelial cells by influenza viruses triggers an immune response. The immune system releases various inflammatory mediators, including cytokines and chemokines, to recruit immune cells to the site of infection. **5. Damage to Respiratory Epithelium** The inflammatory response and the viral replication process cause damage to the respiratory epithelium. This damage disrupts the normal barrier function of the respiratory tract and can lead to increased permeability and susceptibility to secondary bacterial infections. **6. Symptoms and Systemic Effects** The immune response and the viral replication process contribute to the characteristic symptoms of influenza, including fever, cough, sore throat, nasal congestion, body aches, fatigue, and malaise. In some cases, influenza viruses can also enter the bloodstream, leading to systemic symptoms such as headache, chills, and gastrointestinal disturbances. **7. Immune Response** The immune system plays a crucial role in controlling and eliminating the influenza virus. Both the innate immune response (including natural killer cells and macrophages) and the adaptive immune response (including B cells and T cells) are activated to recognize and target the virus for destruction. **8. Antigenic Drift and Shift** Influenza viruses can undergo genetic mutations through antigenic drift and antigenic shift. Antigenic drift refers to small changes in the viral genes over time, leading to the emergence of new strains. Antigenic shift occurs when there is a major genetic reassortment between different influenza viruses, resulting in the sudden emergence of a novel strain. These genetic changes contribute to the annual outbreaks and occasional pandemics of influenza. Understanding the pathophysiology of influenza helps in the development of strategies for prevention, treatment, and control of the disease. Vaccination, antiviral medications, and infection control measures are some of the approaches used to manage influenza and reduce its impact on individuals and communities. **TYPES OF INFLUENZA** Influenza, commonly known as the flu, is caused by influenza viruses. There are three main types of influenza viruses that infect humans: influenza A, influenza B, and influenza C. These types differ in their genetic makeup and their ability to cause widespread illness in humans. Here\'s a brief overview of each type: - **Influenza A** The most common cause of seasonal flu outbreaks and can infect a variety of animal species in addition to humans, including birds and pigs. They are classified into different subtypes based on the two surface proteins, hemagglutinin (H) and neuraminidase (N). The subtypes currently known to infect humans include H1N1 and H3N2, among others. Influenza A viruses have the potential to cause pandemics when a novel subtype emerges that can easily spread between humans. - **Influenza B** Influenza B viruses also circulate widely and are a common cause of seasonal flu. Unlike influenza A, they do not have subtypes but are further categorized into different lineages. Influenza B viruses primarily infect humans and are less likely to cause pandemics compared to influenza A viruses. - **Influenza C** Influenza C viruses also infect humans, but they typically cause milder respiratory symptoms compared to influenza A and B. Influenza C viruses are less common and generally do not cause widespread outbreaks or epidemics. It\'s important to note that each type of influenza virus can further mutate into different strains over time, leading to new variants of the virus. This is why the flu vaccine is updated each year to provide protection against the most prevalent strains. It\'s worth mentioning that avian influenza, or bird flu, is a specific subtype of influenza A virus that primarily affects birds. Influenza viruses can cause seasonal outbreaks and epidemics, with symptoms including fever, cough, sore throat, body aches, fatigue, and respiratory symptoms. It\'s important to practice preventive measures, such as annual vaccination, good hand hygiene, and respiratory etiquette, to reduce the risk of influenza infection. Influenza viruses that infect the upper respiratory tract like H1N1 tend to be more mild but more transmissible, whereas those that infect the lower respiratory tract like H5N1 tend to cause more severe illness but are less contagious. - **Influenza D** Are not known to infect humans and have been observed only in pigs and cattle. **PEOPLE AT RISK OF INFLUENZA** People who are at risk of exposure to influenza include: - Healthcare workers, - Social care workers, - Those who live with or care for people vulnerable to influenza. - In long-term care facilities (the flu can spread rapidly after it is introduced). - Lower temperature - Lower absolute and relative humidity - Less ultraviolet radiation from the Sun - Crowding. Other factors that may increase the risk: - **Age.** Seasonal influenza tends to have worse outcomes in children under age 2, and adults older than age 65. - **Living or working conditions**. People who live or work in facilities with many other residents, such as nursing homes or military barracks, are more likely to develop the flu. People who are staying in the hospital also are at higher risk. - **Weakened immune system.** Cancer treatments, anti-rejection medications, long-term use of steroids, organ transplants, blood cancer, or HIV/AIDS can weaken the immune system. This can make it easier to catch the flu and may increase the risk of developing complications. - **Chronic illnesses.** Chronic conditions may increase the risk of influenza complications. Examples include asthma and other lung diseases, diabetes, heart disease, nervous system diseases, metabolic disorders, problems with the airway, and kidney, liver, or blood disease. - **Race.** American Indians or Alaska Natives people may have an increased risk of influenza complications. - **Aspirin use under age 19.** People who are younger than 19 years of age and receiving long-term aspirin therapy are at risk of developing Reye\'s syndrome if infected with influenza. - **Pregnancy.** Pregnant people are more likely to develop influenza complications, particularly in the second and third trimesters. This risk continues up to two weeks after the baby is born. - **Obesity.** People with a body mass index (BMI) of 40 or higher have an increased risk of flu complications. **SIGNS AND SYMPTOMS OF INFLUENZA** The onset of symptoms is sudden, and initial symptoms are predominately non-specific, including: - Inflammation of the nasal mucosa accompanied by excessive mucous production. - Nasal congestion - Postnasal drip. - Headaches. - Chills/Fever - General malaise (muscle pain or aches - feeling of discomfort). - Loss of appetite. - Confusion. These symptoms are usually accompanied by respiratory symptoms such as: - A dry cough. - Sore or dry throat. - Hoarse voice. - A stuffy or runny nose. - Coughing (most common symptom). - Shortness of breath - Pale, grey, or blue-coloured skin, lip, or nail beds --- depending on skin colour. - Eye pain - Chest pain - Seizures - Dehydration - Worsening of existing medical conditions Gastrointestinal symptoms may also occur, including: - Nausea - Vomiting - Diarrhoea - Gastroenteritis, especially in children. **DIAGNOSIS OF INFLUENZA** Because influenza is like other viral respiratory tract illnesses, laboratory diagnosis is necessary for confirmation. Common ways of collecting samples for testing include nasal and throat swabs. Samples may be taken from the lower respiratory tract if the infection has cleared the upper but not the lower respiratory tract. Diagnostic methods that can identify influenza include viral cultures, antibody- and antigen-detecting tests, and nucleic acid-based tests. Viruses can be grown in a culture of mammalian cells or embryonated eggs for 3--10 days to monitor the cytopathic effect. Final confirmation can then be done via antibody staining, heat absorption using red blood cells, or immunofluorescence microscopy. There are **several tests available** to diagnose influenza (flu) and determine the specific type or strain of the virus. These tests can help healthcare providers confirm a suspected case of influenza and guide appropriate treatment. Here are the commonly used tests for influenza: **1. Rapid Influenza Diagnostic Tests (RIDTs)** RIDTs are rapid point-of-care tests that can provide results within minutes. These tests are often done in clinics or healthcare settings. They detect viral antigens (proteins) present in respiratory specimens (nasal or throat swabs). However, RIDTs have limitations in terms of sensitivity and specificity, and false-negative results can occur. **2. Reverse Transcription Polymerase Chain Reaction (RT-PCR)** RT-PCR is a highly sensitive and specific molecular test used to detect and identify the genetic material (RNA) of the influenza virus. This test can distinguish between different types and subtypes of influenza viruses, including influenza A and B. It is considered the gold standard for influenza diagnosis. RT-PCR is typically performed in specialized laboratories. **3. Nucleic Acid Amplification Tests (NAAT)** NAATs are like RT-PCR and can detect and ampulla kinetic material of the influenza virus. These tests are highly sensitive and specific for influenza diagnosis. **4. Viral Culture** Viral culture involves the growth of the influenza virus in a laboratory setting. It is a time-consuming process and may take several days to obtain results. Viral culture is less commonly used due to the availability of faster diagnostic methods. **TREATMENT/MEDICAL MANAGEMENT OF INFLUENZA** Treatment of influenza in cases of mild or moderate illness is supportive and includes: - Anti-fever medications such as acetaminophen and ibuprofen, adequate fluid intake to avoid dehydration, and resting at home. - Cough drops and throat sprays may be beneficial for sore throat. It is recommended to avoid alcohol and tobacco use while sick with the flu. - Aspirin is not recommended to treat influenza in children due to an elevated risk of developing Reye syndrome. - Corticosteroids likewise are not recommended except when treating septic shock or an underlying medical condition, such as chronic obstructive pulmonary disease or asthma exacerbation, since they are associated with increased mortality. - If a secondary bacterial infection occurs, then treatment with antibiotics may be necessary. - Antiviral drugs are primarily used to treat severely ill patients, especially those with compromised immune systems (most effective when started in the first 48 hours after symptoms appear). Later administration may still be beneficial for those who have underlying immune defects, those with more severe symptoms, or those who have a higher risk of developing complications if these individuals are still shedding the virus. Antiviral treatment is also recommended if a person is hospitalized with suspected influenza instead of waiting for test results to return and if symptoms are worsening. - Vaccination recommendations vary by country. Some recommend it for all people above a certain age, such as 6 months, whereas other limit to high at-risk groups, such as pregnant women, young children (excluding new-borns), the elderly, people with chronic medical conditions, health care workers, people who encounter high-risk people, and people who transmit the virus easily. Young infants cannot receive flu vaccines for safety reasons, but they can inherit passive immunity from their mother if inactivated vaccines are administered to the mother during pregnancy. Influenza vaccination also helps to reduce the probability of reassortment. - Antiviral chemoprophylaxis can be prevented or reduced in severity by post-exposure prophylaxis with the antiviral drugs oseltamivir, which can be taken orally by those at least three months old, and zanamivir, which can be inhaled by those above seven years of age. - Chemoprophylaxis is most useful for individuals at high-risk of developing complications and those who cannot receive the flu vaccine due to contraindications or lack of effectiveness. Post-exposure chemoprophylaxis is only recommended if oseltamivir is taken within 48 hours of contact with a confirmed or suspected influenza case and zanamivir within 36 hours. It is recommended that it be offered to people who are yet to receive a vaccine for the current flu season, who have been vaccinated less than two weeks since contact, if there is a significant mismatch between vaccine and circulating strains, or during an outbreak in a closed setting regardless of vaccination history. - Infection control. Hand hygiene is important in reducing the spread of influenza. This includes frequent hand washing with soap and water, using alcohol-based hand sanitizers, and not touching one\'s eyes, nose, and mouth with one\'s hands. Covering one\'s nose and mouth when coughing or sneezing is important. Other methods to limit influenza transmission include staying home when sick, avoiding contact with others until one day after symptoms end, and disinfecting surfaces likely to be contaminated by the virus, such as doorknobs. Health education through media and posters is often used to remind people of etiquette and hygiene. - There is uncertainty about the use of masks since research thus far has not shown a significant reduction in seasonal influenza with mask usage. Likewise, the effectiveness of screening at points of entry into countries is not well-researched. Social distancing measures such as school closures, avoiding contact with infected people via isolation or quarantine, and limiting mass gatherings may reduce transmission, but these measures are often expensive, unpopular, and difficult to implement. Consequently, the commonly recommended methods of infection control are respiratory etiquette, hand hygiene, and mask-wearing, which are inexpensive and easy to perform. Pharmaceutical measures are effective but may not be available in the early stages of an outbreak. - Infected individuals may be cohorted or assigned to individual rooms. Protective clothing such as masks, gloves, and gowns is recommended when encountering infected individuals if there is a risk of exposure to infected bodily fluids. Keeping patients in negative pressure rooms and avoiding aerosol-producing activities may help, but special air handling and ventilation systems are not considered necessary to prevent the spread of influenza in the air. In residential homes, new admissions may need to be closed until the spread of influenza is controlled. When discharging patients to care homes, it is important to take care if there is a known influenza outbreak. - Since influenza viruses circulate in animals such as birds and pigs, prevention of transmission from these animals is important. Water treatment, indoor raising of animals, quarantining sick animals, vaccination, and biosecurity are the primary measures used. Placing poultry houses and piggeries on high ground away from high-density farms, backyard farms, live poultry markets, and bodies of water helps to minimize contact with wild birds. - Other biosecurity measures include cleaning and disinfecting facilities and vehicles, banning visits to poultry farms, not bringing birds intended for slaughter back to farms, changing clothes, disinfecting foot baths, and treating food and water. - If live poultry markets are not closed, then \"clean days\" when unsold poultry is removed, and facilities are disinfected and \"no carry-over\" policies to eliminate infectious material before new poultry arrive can be used to reduce the spread of influenza viruses. If a novel influenza virus has breached the biosecurity measures, then rapid detection to stamp it out via quarantining, decontamination, and culling may be necessary to prevent the virus from becoming endemic. **DRUGS USED FOR INFLUENZA** In the management of influenza, several types of medications may be used, depending on the specific circumstances and severity of the illness. Here are some examples of drugs commonly used in the treatment and prevention of influenza: **Antiviral Medications:** These drugs specifically target the influenza virus, reducing the severity and duration of symptoms, and potentially preventing complications. They are most effective when started early in the course of illness (within 48 hours of symptom onset). Examples of antiviral medications for influenza include: - Oseltamivir (Tamiflu) - Zanamivir (Relenza) - Peramivir (Rapivab) - Baloxavir marboxil (Xofluza) **Over-the-Counter Symptom Relief:** Various over-the-counter medications can help alleviate the symptoms of influenza, although they do not directly target the virus. These may include: Acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) to reduce fever, relieve pain, and alleviate body aches. - **Cough suppressants, expectorants**, or combination cough and cold medications to relieve cough and congestion symptoms. - **Decongestants** (oral or nasal sprays) to temporarily relieve nasal congestion It\'s important to follow the instructions on the package and consult a healthcare professional if you have any specific concerns or if the symptoms worsen. - **Prescription Medications for Complications:** In cases where influenza leads to complications such as pneumonia or bacterial infections, additional medications may be prescribed to treat the underlying condition. These may include: - **Antibiotics:** These are used to treat bacterial infections that can occur because of influenza, such as pneumonia or sinusitis. However, antibiotics are not effective against the influenza virus itself. - **Other supportive medications:** Depending on the specific complications, additional medications, such as bronchodilators for wheezing or supplemental oxygen for respiratory distress, may be prescribed to manage associated symptoms. It\'s important to note that the use of antiviral medications and other prescription medications should be determined by a healthcare professional based on individual circumstances, severity of symptoms, and risk factors. The choice and timing of medication initiation may vary depending on guidelines and recommendations from local health authorities. **PREVENTION OF INFLUENZA** Prevention through annual influenza vaccination is one of the most effective ways to reduce the risk of influenza infection. Vaccination is recommended for individuals aged six months and older, and specific vaccines are updated each year to target the most prevalent strains of influenza. **1. Flu vaccines** The U.S. Centres for Disease Control and Prevention (CDC) recommends annual flu vaccination for everyone age 6 months or older. The flu vaccine can lower your risk of getting the flu. It also can lower the risk of having serious illness from the flu and needing to stay in the hospital. Vaccination is the best way to protect against both. Flu vaccination could lessen symptoms that might be confused with those caused by COVID-19. Preventing the flu and lowering the number of people with severe flu and complications could also lower the number of people needing to stay in the hospital. **2. Nasal spray** The nasal spray is approved for people between 2 and 49 years old. It isn\'t recommended for some groups, such as: - Children younger than age 2 - Adults aged 50 and older. - Pregnant people - Children between 2 and 17 years old who are taking aspirin or a salicylate-containing medication. - People with weakened immune systems. - Kids 2 to 4 years old who have had asthma or wheezing in the past 12 months. - If you have an egg allergy, you can still get a flu vaccine. - The influenza vaccine isn\'t 100% effective, so it\'s also important to take several measures to reduce the spread of infection, including: **3. Wash your hands.** Washing your hands often with soap and water for at least 20 seconds is an effective way to prevent many common infections. Or use alcohol-based hand sanitizers if soap and water aren\'t available. **4. Avoid touching your face.** Avoid touching your eyes, nose, and mouth. **5. Cover your coughs and sneezes.** Cough or sneeze into a tissue or your elbow. Then wash your hands. **6. Clean surfaces.** Regularly clean often-touched surfaces to prevent the spread of infection from touching a surface with the virus on it and then your face. **7. Avoid crowds.** The flu spreads easily wherever people gather (childcare centres, schools, office buildings, auditoriums, and public transportation) so avoid crowds during peak flu season, **8. Also avoid anyone who is sick.** And if you\'re sick, stay home for at least 24 hours after your fever is gone so that you lessen your chance of infecting others. **COMPLICATIONS OF INFLUENZA** If you\'re young and healthy, the flu usually isn\'t serious. Although you may feel miserable while you have it, the flu usually goes away in a week or two with no lasting effects. But children and adults at high risk may develop complications that may include: - Pneumonia (the most serious complications. For older adults and people with a chronic illness, pneumonia can be deadly). - Bronchitis - Asthma flare-ups - Heart problems - Ear infections - Acute respiratory distress syndrome **NURSING DIAGNOSIS FOR PATIENTS WITH INFLUENZA** When caring for patients with influenza, nurses may formulate nursing diagnoses to guide their care. Here are some possible nursing diagnoses for influenza: 1\. Impaired Gas Exchange related to inflammation and decreased lung capacity secondary to influenza. 2\. Ineffective Airway Clearance related to increased mucus production and airway inflammation. 3\. Risk for Infection related to the presence of the influenza virus and compromised immune system. 4\. Acute Pain related to sore throat, headache, body aches, and muscle pain associated with influenza. 5\. Hyperthermia related to fever caused by the influenza virus. 6\. Fatigue related to the systemic effects of the influenza infection. 7\. Risk for Fluid Volume Deficit related to fever, sweating, and decreased fluid intake. 8\. Knowledge Deficit regarding influenza prevention, symptom management, and when to seek medical help. 9\. Anxiety related to the uncertainty of the illness, fear of complications, or spread of the infection. 10\. Social Isolation related to the need for respiratory isolation and precautionary measures to prevent the spread of influenza. **LIVING WITH INFLUENZA** Living with influenza typically involves managing the symptoms, taking appropriate precautions to prevent the spread of the virus, and allowing sufficient time for recovery. Here are some considerations for living with influenza: **1. Rest and Hydration** Get plenty of rest to allow your body to recover. Adequate hydration is also important to prevent dehydration, especially if you have a fever. Drink plenty of fluids, such as water, herbal tea, and clear soups, to stay hydrated. **2. Medications** Take prescribed antiviral medications as directed by your healthcare provider. These medications can help reduce the duration and severity of influenza symptoms. Over-the-counter pain relievers, such as acetaminophen or ibuprofen, may be used to alleviate fever, body aches, and headaches. Follow the recommended dosage instructions and consult your healthcare provider if you have any concerns or questions. **3. Symptom Management** Use over-the-counter remedies, such as cough suppressants, throat lozenges, or saline nasal sprays, to alleviate specific symptoms like cough, sore throat, or congestion. Follow the instructions on the packaging or consult with a pharmacist if you have any doubts. **4. Isolation and Preventive Measures** Influenza is highly contagious, so it\'s important to take precautions to prevent spreading the virus to others. Stay at home and avoid close contact with people who are not infected. Cover your mouth and nose when coughing or sneezing, preferably with a tissue or your elbow. Dispose of used tissues properly and practice good hand hygiene by washing your hands frequently with soap and water or using hand sanitizer. **5. Follow Medical Advice** Stay in touch with your healthcare provider and follow their instructions. Attend follow-up appointments as needed and seek medical attention if your symptoms worsen or if you develop any complications. **6. Supportive Care** Seek support from family members, friends, or healthcare professionals to help with daily tasks and responsibilities while you recover. Don\'t hesitate to ask for assistance when needed. **7. Self-Care** Take care of yourself by eating nutritious meals, getting adequate sleep, and engaging in activities that promote relaxation and well-being. Avoid smoking and exposure to second-hand smoke, as it can worsen respiratory symptoms. **PNEUMONIA** Pneumonia may be caused by the primary viral infection or by a secondary bacterial infection. Primary pneumonia is characterized by rapid progression of fever, cough, laboured breathing, and low oxygen levels that cause bluish skin. It is especially common among those who have an underlying cardiovascular disease such as rheumatic heart disease. Secondary pneumonia typically has a period of improvement in symptoms for 1--3 weeks followed by recurrent fever, sputum production, and fluid build-up in the lungs, but can also occur just a few days after influenza symptoms appear. Most of the time your body filters germs out of the air that you breathe. Sometimes germs, such as bacteria, viruses, or fungi, get into the lungs and cause infections. When these germs get into the lungs, your immune system, which is your body\'s natural defence against germs, goes into action. Immune cells attack the germs and may cause inflammation of the air sacs, or alveoli. Inflammation can cause your air sacs to fill up with fluid and pus and cause pneumonia symptoms. **MODE OF TRANSMITION OF PNEUMONIA** Some types of pneumonia are contagious, meaning it spreads from person to person. Pneumonia is mostly spread when people infected cough, sneeze, or talk, sending respiratory droplets into the air. These droplets can then be inhaled by close contact. Less often, one can get pneumonia from touching an object or surface that has the germ on it and then touching the nose or mouth. Not everyone who is exposed to pneumonia will develop it and some people are at increased risk for getting pneumonia. **TYPES OF PNEUMONIA** **1. Bacteria** The most common type of bacterial pneumonia is called pneumococcal pneumonia caused by the Streptococcus pneumoniae germ that normally lives in the upper respiratory tract. It can occur on its own or develop after a boot of a viral cold or the flu and often affects just one part, or lobe, of a lung. When this happens, the condition is called lobar pneumonia. Those at greatest risk for bacterial pneumonia include people recovering from surgery, people with respiratory disease or viral infection and people who have weakened immune systems. Some types of bacteria because what is known as \"atypical\" pneumonia, including: - **Mycoplasma pneumoniae**, a tiny wide-spread bacterium that usually infects people younger than 40 years old, especially those living and working in crowded conditions. The illness is often mild enough to go undetected and is sometimes referred to as walking pneumonia. - **Chlamydophila pneumoniae**, which commonly causes upper respiratory infections year-round, but can also result in a mild form of pneumonia. - **Legionella pneumophila**, which causes a dangerous form of pneumonia called Legionnaire\'s disease. Unlike other bacterial pneumonias, Legionella is not passed from person to person. Outbreaks of the disease have been linked to exposure to contaminated water from cooling towers, whirlpool spas, and outdoor fountains. These bacteria are referred to as \"atypical\" because pneumonia caused by these organisms might have slightly different symptoms, appear different on a chest X-ray, or respond to different antibiotics than the typical bacteria that cause pneumonia. Even though these infections are called \"atypical,\" they are not uncommon. **2. Viruses** Viruses that infect the upper respiratory tract may also cause pneumonia. SARS-CoV-2, the virus that causes COVID-19, and the influenza virus are the most common cause of viral pneumonia in adults. Respiratory syncytial virus (RSV) is the most common cause of viral pneumonia in young children. Most viral pneumonia are not serious and last a shorter time than bacterial pneumonia. - COVID-19 pneumonia can be severe, causing low levels of oxygen in the blood and leading to respiratory failure and in many cases a condition called acute respiratory distress syndrome (ARDS). Viral pneumonia caused by the SARS-CoV-2 virus generally occurs in both lungs. As the lungs fill with fluid, oxygen exchange becomes more difficult and results in breathing difficulties. Recovery may take months before symptoms ease. Viral pneumonia caused by the influenza virus may be severe and sometimes fatal. The virus invades the lungs and multiplies; however, there are almost no physical signs of lung tissue becoming filled with fluid. This pneumonia is most serious in people who have pre-existing heart or lung disease and pregnant women. Viral pneumonias may be complicated by a secondary invasion of bacteria, with all the typical symptoms of bacterial pneumonia. **3. Fungi** Fungal pneumonia is most common in people with chronic health problems or weakened immune systems, and in people who are exposed to large doses of certain fungi from contaminated soil or bird droppings. Pneumonia caused by fungi are not contagious. - Pneumocystis pneumonia is a serious fungal infection caused by Pneumocystis groves. It occurs in people who have weak immune systems due to HIV/AIDS or the long-term use of medicines that suppress their immune systems, such as those used to treat cancer or manage organ transplants. The following are three fungi that occur in the soil in some parts of the United States and can cause some people to get pneumonia. - Coccidioidomycosis. This fungus is found in Southern California and the desert Southwest. It is the cause of valley fever. - Histoplasmosis. This fungus is found in the Ohio and Mississippi River Valleys. - Cryptococcus. This fungus is found throughout the United States in bird droppings and soil contaminated with bird droppings. **CAUSES OF PNEUMONIA** About a third of primary pneumonia cases are followed by secondary pneumonia, which is most frequently caused by the bacteria Streptococcus pneumoniae and Staphylococcus aureus. Pneumonia caused by influenza viruses is characterized by high levels of viral replication in the lower respiratory tract, accompanied by a strong pro-inflammatory response called a cytokine storm. In bacterial infections, early depletion of macrophages during influenza creates a favourable environment in the lungs for bacterial growth since these white blood cells are important in responding to bacterial infection. Host mechanisms to encourage tissue repair may inadvertently allow bacterial infection. Infection also induces production of systemic glucocorticoids that can reduce inflammation to preserve tissue integrity but allow increased bacterial growth. Infection that inflames air sacs in one or both lungs, which may fill with fluid. With pneumonia, the air sacs may fill with fluid or pus. The infection can be life-threatening to anyone, but particularly to infants, children, and people over 65. Pneumonia is mostly spread when people infected cough, sneeze or talk, sending respiratory droplets into the air. These droplets can then be inhaled by close contacts. Less often, you can get pneumonia from touching an object or surface that has the germ on it and then touching your nose or mouth. There is no set time for how long you'll be contagious once you have pneumonia. The time you may spread pneumonia to others is dependent on the type of pneumonia and what caused you to have it. Generally, if you have bacterial pneumonia, you are contagious for around 48 hours after starting antibiotics and your fever has gone away. If it is viral pneumonia, as symptoms start to go away (especially fever) so does the contagious period. **HIGH-RISK GROUP FOR PNEUMONIA** It\'s especially important to get medical attention for pneumonia if you are in a high-risk group, including: - **Age** Pneumonia can affect people of all ages. However, two age groups are at higher risk of developing pneumonia and having more serious pneumonia: - Babies and children, 2 years old or younger, are at higher risk because their immune systems are still developing. This risk is higher for premature babies. - Older adults, age 65 or older, are also at higher risk because their immune systems generally weaken as people age. Older adults are also more likely to have other chronic (long-term) health conditions that raise the risk of pneumonia. - **Lifestyle habits** - Smoking cigarettes can make the person less able to clear mucus from your airways. - Using drugs or alcohol can weaken the immune system and are also more likely to accidentally breathe in saliva or vomit into the windpipe if you are sedated or unconscious from an overdose. - Other medical conditions - **Environment or occupation** - People who live or spend a lot of time in crowded place such as military barracks, prisons, homeless shelters, or nursing homes. - People who regularly breathe in air pollution or toxic fumes. - People who encounter germs as they work in a chicken or turkey processing centre, pet shop, or veterinary clinic. - People who have chronic underlying (ongoing) diseases, serious long-term health problems, or weak immune systems. This may include people who have cancer, HIV, asthma, sickle cell disease, or damaged or removed spleens. People who have any of the following medical conditions: Brain disorders, such as a stroke, a head injury, dementia, or Parkinson's disease can affect the ability to cough or swallow. This can lead to food, drink, vomit, or saliva going down your windpipe instead of your oesophagus and getting into the lungs. Conditions that weaken immune system may also increase the risk. These include pregnancy, HIV/AIDS, or an organ or bone marrow transplant. Chemotherapy, which is used to treat cancer, and long-term use of steroid medicines can also weaken the immune system. Critical diseases that require hospitalization, including receiving treatment in a hospital intensive care unit, can raise the risk of hospital-acquired pneumonia. The risk is higher if one cannot move around much or are sedated or unconscious. Using a ventilator raises the risk of a type called ventilator-associated pneumonia. Lung diseases, such as asthma, bronchiectasis, cystic fibrosis, or COPD, also increase your pneumonia risk. Other serious conditions, such as malnutrition, diabetes, heart failure, sickle cell disease, or liver or kidney disease, are additional risk factors. **SIGNS AND SYMPTOMS OF PNEUMONIA** Pneumonia symptoms can vary from so mild (barely notice), to so severe needing hospitalization. How the body responds to pneumonia depends on the type of germ causing the infection, age, and overall health. Early symptoms are like influenza symptoms: fever, a dry cough, headache, muscle pain, and weakness. Within a day or two, the symptoms typically get worse, with increasing cough, shortness of breath and muscle pain. There may be a high fever and there may be blueness of the lips. Mild signs and symptoms often are like those of a cold or flu, but they last longer. The signs and symptoms of pneumonia may include: - Cough, which may produce greenish, yellow, bloody mucus or phlegm. - Fever, sweating and shaking chills. - Shortness of breath - Difficulty breathing, - Bluish colouration of the lips and fingertips, - Chest pain when breathing or coughing. - Rapid, shallow breathing - Sharp or stabbing chest pain that gets worse when you breathe deeply or cough. - Confusion or changes in mental awareness (in adults aged 65 and older) - Fatigue - Lower than normal body temperature (in adults older than age 65 and people with weak immune systems) - Nausea, vomiting, or diarrhoea. - Loss of appetite, low energy, and fatigue Bacterial pneumonia, which is the most common form, tends to be more serious than other types of pneumonia, with symptoms that require medical care. The symptoms of bacterial pneumonia can develop gradually or suddenly. Fever may rise as high as a dangerous 105 degrees F, with profuse sweating and rapidly increased breathing and pulse rate. Lips and nailbeds may have a bluish colour due to a lack of oxygen in the blood. A patient\'s mental state may be confused or delirious. Viral pneumonia usually develops over a period of several days. Early symptoms are like influenza symptoms: fever, a dry cough, headache, muscle pain, and weakness. Within a day or two, the symptoms typically get worse, with increasing cough, shortness of breath, and muscle pain. There may be a high fever and there may be blueness of the lips. Symptoms may vary in certain populations. Newborns and infants may not show any signs of the infection. Or, they may vomit, have a fever and cough, or appear restless, sick, or tired and without energy. Older adults and people who have serious illnesses or weak immune systems may have fewer and milder symptoms. They may even have a lower-than-normal temperature. Older adults who have pneumonia sometimes have sudden changes in mental awareness. For individuals that already have a chronic lung disease, those symptoms may worsen. **DIAGNOSIS OF PNEUMONIA** Sometimes pneumonia can be difficult to diagnose because the symptoms are so variable and are often very similar to those seen in a cold or influenza. To diagnose pneumonia, and to try to identify the germ that is causing the illness, your doctor will ask questions about your medical history, do a physical exam, and run some tests. **1. Medical history** Questions will be asked about signs and symptoms, how and when they began. To help figure out if the infection is caused by bacteria, viruses, or fungi. Some questions about possible exposures may be asked such as: - Any recent travel - Occupation - Contact with animals. - Exposure to other sick people at home, work, or school - Whether you have recently had another illness **2. Physical exam** The lungs with be listened to with a stethoscope. If there is pneumonia, the lungs may make crackling, bubbling, and rumbling sounds when inhaling. **3. Diagnostic Tests** Tests will be recommended to confirm the diagnosis and learn more about infection. These may include: - Blood tests to confirm the infection and to try to identify the germ that is causing the illness. - Chest X-ray to look for the location and extent of inflammation in the lungs. - Pulse oximetry to measure the oxygen level in the blood. Pneumonia can prevent your lungs from moving enough oxygen into the bloodstream. - Sputum test on a sample of mucus (sputum) taken after a deep cough, to look for the source of the infection. If considered a high-risk patient because of age and overall health, or if hospitalized, the doctors may want to do some additional tests, including: - CT scan of the chest to get a better view of the lungs and look for abscesses or other complications. - Arterial blood gas test, to measure the amount of oxygen in a blood sample taken from an artery, usually in your wrist. This is more accurate than the simpler pulse oximetry. - Pleural fluid culture, which removes a small amount of fluid from around tissues that surround the lung, to analyse and identify bacteria causing pneumonia. - Bronchoscopy, a procedure used to investigate the lungs\' airways. If you are hospitalized and your treatment is not working well, doctors may want to see whether something else is affecting your airways, such as a blockage. They may also take fluid samples or a biopsy of lung tissue. - Auscultation - Percussion **MEDICAL MANAGEMENT OF PNEUMONIA** Treatment for pneumonia depends on your risk factors and how serious your pneumonia is. Many people who have pneumonia are prescribed medicine and recover at home. This may need to be treated in the hospital or an intensive care unit (ICU) if your pneumonia is serious. The following medicines to treat pneumonia at home or at the hospital, depending on how sick that individual is: - **Management at home** - If your pneumonia is mild, the healthcare provider may prescribe medicines or suggest over-the-counter medicines to treat it at home. - Antibiotics may be prescribed for bacterial pneumonia. Most people begin to feel better after one to three days of antibiotic treatment. However, you should take antibiotics as the doctor prescribes. If stop too soon, the pneumonia may come back. - Antiviral medicine is sometimes prescribed for viral pneumonia. However, these medicines do not work against every virus that causes pneumonia. - Antifungal medicines are prescribed for fungal pneumonia. - Over-the-counter medicines may be recommended to treat the fever and muscle pain or help them breathe easier. - **Management at the hospital** If the pneumonia is serious, it may be treated in a hospital so one can get antibiotics and fluids through an intravenous (IV) line inserted into the vein. The individual may also get oxygen therapy to increase the amount of oxygen in the blood. If the pneumonia is very serious, that person may need to be put on a ventilator. - Procedures/Surgery A procedure or surgery to remove seriously infected or damaged parts of the lung may be needed. This may help recovery and may prevent the pneumonia from coming back. - Choose heart-healthy foods because good nutrition helps the body recover. - Drink plenty of fluids to help stay hydrated. - Don't drink alcohol or use illegal drugs. Alcohol and illegal drugs weaken your immune system and can raise the risk of pneumonia complications. - Don't smoke and avoid second-hand smoke. Breathing in smoke can worsen your pneumonia. - Get plenty of sleep. Good quality sleep can help the body rest and improve the response of the immune system. - Get light physical activity. Moving around can help regain strength and improve recovery. However, shortness of breath may still be felt. Activity that is too strenuous may make the person dizzy. - Sit upright to help you feel more comfortable and breathe more easily. - Take a couple of deep breaths several times a day. - Monitor condition. - Schedule follow-up care if symptoms does not improve. - Pulmonary rehabilitation to help breathe better as the lungs recover. - Physical therapy to help regain strength. Physical activity can help improve recovery. **DRUGS USED FOR PNEUMONIA** The choice of drugs for pneumonia treatment depends on several factors, including the type of pneumonia (community-acquired, hospital-acquired, or ventilator-associated), the severity of the infection, the presence of risk factors or underlying conditions, and local antimicrobial resistance patterns. Here are some commonly used drugs for the treatment of pneumonia: **Antibiotics:** - Macrolides (e.g., azithromycin, clarithromycin) - Fluoroquinolones (e.g., levofloxacin, moxifloxacin) - Beta-lactam/beta-lactamase inhibitor combinations (e.g., amoxicillin-clavulanate) - Cephalosporins (e.g., ceftriaxone, cefotaxime) - Penicillin (e.g., ampicillin) **Antiviral Medications** (for viral pneumonia caused by specific viruses): - Oseltamivir (Tamiflu) - Zanamivir (Relenza) - Baloxavir marboxil (Xofluza) - Adjunctive Therapies: **Corticosteroids** (may be considered in specific cases, such as severe community-acquired pneumonia or acute respiratory distress syndrome) Oxygen therapy (for patients with severe respiratory distress or hypoxemia) It\'s important to note that the selection of antibiotics should be guided by local guidelines, susceptibility patterns, and individual patient factors. The specific drug regimen and duration of treatment will be determined by the healthcare provider based on the patient\'s clinical presentation and test results. It is crucial to follow the prescribed medication regimen, complete the full course of antibiotics, and report any adverse reactions or concerns to the healthcare provider. Self-medication or the use of antibiotics without a prescription is strongly discouraged, as it can contribute to antimicrobial resistance and may not effectively target the specific bacteria causing pneumonia. **PREVENTION OF PNEUMONIA** Pneumonia can be very serious and even life-threatening therefore take a few steps to try and prevent it. - Vaccines can help prevent some types of pneumonia caused by pneumococcus bacteria or the flu virus. Vaccines cannot prevent all cases of pneumonia. However, compared to people who don\'t get vaccinated, those who are vaccinated and still get pneumonia tend to have: - Good hygiene (washing your hands often), - Quitting smoking (smoking prevents the lungs from properly filtering out and defending the body against germs). - Keeping your immune system strong by getting regular physical activity and eating healthy are other ways to lower the risk of getting pneumonia. - Cover nose and mouth while coughing or sneezing. - Get rid of used tissues right away. - Limit contact with family and friends. - Wash your hands often with soap and water or alcohol-based hand sanitizers to kill germs, especially after coughing and sneezing. - Some people get pneumonia again and again. Report such to the healthcare provider if this happens. - If there is a problem with swallowing, eat smaller meals of thickened food and sleep with the head of the bed raised up (these steps can help avoid getting food, drink, or saliva into the lungs). - If immune system is impaired or weakened, healthcare provider may recommend antibiotics to prevent bacteria from growing in your lungs. - For a planned surgery, it may be recommended that not eat for 8 hours or drink liquids for 2 hours before the surgery. This can help prevent food or drink from getting into the airway while being sedated. **NURSING DIAGNOSIS FOR PNEUMONIA** When caring for patients with pneumonia, nurses may formulate nursing diagnoses to guide their care. Here are some possible nursing diagnoses for pneumonia: 1\. Impaired Gas Exchange related to alveolar-capillary membrane changes and ventilation-perfusion (V/Q) mismatch. 2\. Ineffective Airway Clearance related to increased mucus production, airway inflammation, and impaired cough reflex. 3\. Acute Pain related to inflammation of lung tissue, coughing, and deep breathing. 4\. Risk for Infection related to invasive procedures, compromised immune system, and exposure to pathogens. 5\. Activity Intolerance related to decreased oxygenation, respiratory distress, and fatigue. 6\. Imbalanced Nutrition: Less Than Body Requirements related to anorexia, increased metabolic demand, and difficulty breathing. 7\. Ineffective Breathing Pattern related to chest pain, shortness of breath, and lung congestion. 8\. Anxiety related to difficulty breathing, fear of suffocation, and uncertainty about the illness. 9\. Deficient Knowledge regarding pneumonia, its causes, treatment, and prevention. 10\. Impaired Social Interaction related to isolation precautions and limited mobility. **PROGNOSIS OF PNEUMONIA** The prognosis of pneumonia can vary depending on several factors, including the type and severity of pneumonia, the age and overall health of the patient, the presence of any underlying medical conditions, and the promptness and effectiveness of treatment. **1. Generally Favourable** With appropriate and timely treatment, most cases of pneumonia have a favourable prognosis. Most individuals with community-acquired pneumonia recover completely without any long-term complications. **2. Severity and Complications** The prognosis can be influenced by the severity of pneumonia and the presence of complications. Severe pneumonia, particularly in vulnerable populations (such as the elderly, young children, and those with weakened immune systems), can lead to a higher risk of complications and poorer outcomes. Complications can include respiratory failure, sepsis, lung abscesses, empyema (accumulation of pus in the pleural cavity), and pleural effusion (accumulation of fluid in the pleural space). **3. Underlying Health Conditions** The presence of underlying medical conditions, such as chronic lung diseases (e.g., chronic obstructive pulmonary disease - COPD), heart disease, diabetes, or immunosuppression, can affect the prognosis of pneumonia. **4. Age** Age plays a role in the prognosis of pneumonia. Older adults, particularly those over the age of 65, may have a higher risk of complications and a longer recovery time compared to younger individuals. **5. Timely and Appropriate Treatment** Early recognition, prompt medical intervention, and appropriate antibiotic therapy are important factors in achieving a favourable prognosis. Treatment is guided by the underlying cause of pneumonia, such as bacterial, viral, or fungal infection. Antibiotics are prescribed for bacterial pneumonia, while antiviral medications may be used for viral pneumonia. **6. Vaccination** Vaccination against common pathogens that cause pneumonia, such as the pneumococcal vaccine and influenza vaccine, can help prevent pneumonia and reduce its severity if contracted. **7. Follow-up Care** Following recovery from pneumonia, some individuals may experience lingering symptoms or a slower return to their baseline health. Close monitoring and follow-up care are essential to ensure complete resolution and address any lingering issues. It\'s important to note that the prognosis of pneumonia can vary widely among individuals, and each case should be evaluated and managed on an individual basis. Early detection, appropriate treatment, and adherence to healthcare recommendations are key factors in improving the prognosis and reducing the risk of complications. **COMPLICATIONS OF PNEUMONIA** Pneumonia is an infection that can lead to various complications, particularly if not properly managed or if certain risk factors are present. Some of the potential complications of pneumonia include: **1. Respiratory Failure** In severe cases of pneumonia, the infection can spread and cause significant damage to the lungs, leading to respiratory failure. This occurs when the lungs are unable to provide sufficient oxygen to the body or remove carbon dioxide effectively. **2. Pleural Effusion** Pneumonia can result in the accumulation of fluid in the space between the lungs and the chest wall, known as a pleural effusion. This can cause chest pain, shortness of breath, and decreased lung function. **3. Lung Abscess** In some cases, a localized area of pus may form within the lung tissue, leading to a lung abscess. This can cause symptoms such as persistent cough, chest pain, fever, and coughing up foul-smelling or bloody sputum. **4. Empyema** Empyema is a more severe form of pleural effusion in which the fluid becomes infected. It can cause severe chest pain, difficulty breathing, and systemic symptoms such as fever and fatigue. **5. Sepsis** Pneumonia can lead to the development of sepsis, a life-threatening condition characterized by a widespread infection throughout the body. Sepsis can cause organ dysfunction, low blood pressure, and other severe complications. **6. Acute Respiratory Distress Syndrome (ARDS)** In some cases, pneumonia can trigger an excessive inflammatory response in the lungs, leading to acute respiratory distress syndrome. ARDS is a severe condition that impairs oxygen exchange in the lungs and can require intensive care management. **7. Cardiac Complications** Pneumonia can strain the heart, particularly in individuals with pre-existing heart conditions. It can lead to complications such as arrhythmias, myocarditis (inflammation of the heart muscle), or exacerbation of heart failure. **8. Lung Scarring** In certain cases, pneumonia can result in the formation of scar tissue in the lungs, leading to long-term respiratory complications and reduced lung function. It is important to seek medical attention promptly if symptoms of pneumonia develop or worsen. Early diagnosis and appropriate treatment can help reduce the risk of complications. Treatment typically involves antibiotics, supportive care, and addressing underlying risk factors. **LIVING WITH PNEUMONIA** Living with pneumonia involves taking appropriate steps to manage the condition, support the healing process, and prevent complications. Here are some considerations for living with pneumonia: **1. Follow Medical Treatment** Take prescribed medications, such as antibiotics or antivirals, as directed by your healthcare provider. Finish the full course of antibiotics even if you start feeling better to ensure complete eradication of the infection. **2. Rest and Allow Recovery** Pneumonia can be physically demanding, so it\'s important to get plenty of rest and avoid overexertion. Listen to your body and give yourself time to recover. Gradually increase activity levels as advised by your healthcare provider. **3. Stay Hydrated** Drink plenty of fluids, such as water, herbal tea, and clear soups, to stay hydrated. Good hydration helps thin and loosen mucus, making it easier to clear from your lungs. **4. Manage Symptoms** Take over-the-counter pain relievers, such as acetaminophen or ibuprofen, as recommended by your healthcare provider, to help reduce fever and alleviate any discomfort or pain associated with pneumonia. Use cough suppressants or expectorants as advised by your healthcare provider to manage cough symptoms. **5. Practice Good Respiratory Hygiene** Cover your mouth and nose with a tissue or your elbow when coughing or sneezing to prevent the spread of germs. Dispose of used tissues properly and wash your hands thoroughly afterward. **6. Maintain a Healthy Lifestyle** Eat a nutritious diet to support your immune system and aid in recovery. Include fruits, vegetables, whole grains, and lean proteins in your meals. Avoid smoking and exposure to second-hand smoke, as it can worsen respiratory symptoms and delay healing. **7. Monitor Symptoms** Keep track of your symptoms and report any changes or concerns to your healthcare provider. Watch for signs of worsening respiratory distress, such as increased shortness of breath, chest pain, or persistent fever, and seek medical attention if needed. **8. Follow-Up Care** Attend follow-up appointments as scheduled with your healthcare provider. They will assess your progress, conduct necessary tests, and adjust your treatment plan if required. **9. Seek Support** Reach out to your healthcare provider, family, or friends for support during your recovery. They can help with daily tasks, provide emotional support, and assist you in adhering to your treatment plan. **ASTHMA** A condition in which a person\'s airways become inflamed, narrow, and swell and produce extra mucus, which makes it difficult to breathe. Asthma is a chronic inflammatory disease of the airways characterized by hyperresponsiveness, mucosal oedema, and mucus production. Asthma can be minor (acute), or it can interfere with daily activities. In some cases, it may lead to a life-threatening attack. Chronic asthma can last for years or be lifelong It is very common. More than 1.5 million cases per year (Nigeria) Treatable by a medical professional and requires a medical diagnosis. Lab tests or imaging often required. Some people's immune systems react poorly to specific chemicals, such as pollen, dust, or animal dander. When allergic people are exposed to these allergens, they experience breathing difficulties. Asthma is due to chronic coughing or other factors, the windpipes swell and narrow, impairing natural airflow in asthma. Asthma affects about 7--10 percent of children and about 7--9 percent of adults, and hence it is a significant public health issue in countries worldwide. However, most deaths from the disorder occur in underdeveloped countries. **CAUSES, RISK/PREDISPOSING FACTORS OF ASTHMA** Asthmatic episodes may begin suddenly or chronic. Although an initial episode can occur at any age, about half of all cases occur in persons younger than 10 years of age, boys being affected more often than girls. Among adults, however, women are affected more often than men. When asthma develops in childhood, it is often associated with an inherited susceptibility to allergens (substances, such as pollen, dust mites, or animal dander, that may induce an allergic reaction). In adults, asthma may develop in response to allergens, but viral infections, aspirin, weather conditions, and exercise may cause it as well. In addition, stress may exacerbate symptoms. Adults who develop asthma may also have chronic rhinitis, nasal polyps, or sinusitis. Adult asthma is sometimes linked to exposure to certain materials in the workplace, such as chemicals, wood dusts, and grains. These substances provoke both allergic and nonallergic forms of the disease. In most of these cases, symptoms will subside if the causative agent is removed from the workplace. Asthma is classified based on the degree of symptom severity, which can be divided into four categories: mild intermittent, mild persistent, moderate persistent, and severe persistent. These chemicals can cause spasmodic contraction of the smooth muscle surrounding the bronchi, swelling and inflammation of the bronchial tubes, and excessive secretion of mucus into the airways. The inflamed, mucus-clogged airways act as a one-way valve---i.e., air is inspired but cannot be expired. The obstruction of airflow may resolve spontaneously or with treatment. Risk factors for asthma include: - Family history - Allergy - Chronic exposure to airway irritants or allergens such as grass, weed pollens, mould, dust, or animals. Asthma can be triggered commonly and exacerbated through: - Airway irritants - Exercise - Stress or emotional upset - Rhinosinusitis with postnasal drip - Medications - Viral respiratory - Infections - Gastroesophageal reflux. - The exact cause is unknown. - Usually triggered by an immune system response to a substance in the lungs: - Chronic obstructive pulmonary disease (COPD), including emphysema and chronic bronchitis. - Smoking tobacco (the main cause) - Exposure to second-hand smoke - A history of respiratory infections - Exposure to air pollutants in the home and workplace - Genetic factors, such as alpha-1 deficiency - Bronchiectasis - Tuberculosis (A bacterium called Mycobacterium tuberculosis) - Allergic bronchopulmonary aspergillosis (ABPA) - Alpha1-antitrypsin (AAT) deficiency - Autoimmune diseases - Autosomal dominant polycystic kidney disease (ADPKD) - Bronchial obstruction - Congenital anatomic defects - Connective-tissue disorders - Cystic fibrosis or young syndrome - Foreign body aspiration - Idiopathic inflammatory disorders - Immunodeficiency states, both genetic and acquired, such as HIV/AIDS - Primary bacterial or viral infections - Primary ciliary dyskinesia - Toxic gas exposure - Traction from other processes - Acute bronchitis - Viruses such as influenza, the common cold, or whooping cough - Sometimes caused by bacteria. - Pulmonary fibrosis - Autoimmune problems - Certain medications - Exposure to triggers - Radiation - Workplace exposures - Sarcoidosis - Cause may be genetic, or bacteria, viruses, or chemicals may be triggers. - Lung cancer - Smoking (main cause of all types of lung cancer) - Exposure to second-hand smoke - Air pollution - Workplace exposure to diesel exhaust, asbestos, or other chemicals - Exposure to radon - Genetic changes - Pneumonia - Bacteria - Viruses - Fungi - Airbags - Moulds - Carpets - Flour - Fireworks - Animal furs or feathers - Humidifiers - Hot tubs - Candles - Pulmonary oedema - Congestive heart failure - Certain medicines - High altitude exposure - Kidney failure - Narrowed arteries that bring blood to the kidneys. - Lung damage caused by poisonous gas or severe infection. - Major injury - Influenza - Influenza virus - Cystic fibrosis - An abnormal gene inherited from both parents. - Mesothelioma - The main cause is asbestos exposure. - Pulmonary hypertension **PATHOPHYSIOLOGY OF ASTHMA** The pathological process of asthma begins with the inhalation of an irritant or an allergen, which then, due to bronchial hypersensitivity, leads to airway inflammation and an increase in mucus production. This leads to a significant increase in airway resistance, which is most pronounced upon expiration. If not corrected rapidly, asthma may become more difficult to treat, as the mucus production prevents the inhaled medication from reaching the mucosa (Hashmi et al., 2022). The pathophysiology of asthma involves a complex interplay of inflammation, bronchoconstriction, and airway hyperresponsiveness. Here is a simplified explanation of the key processes involved: 1. **Inflammation** Asthma is characterized by chronic airway inflammation. In susceptible individuals, exposure to triggers, such as allergens (pollen, dust mites, pet dander), irritants (tobacco smoke, air pollution), or respiratory infections, leads to an inflammatory response in the airways. This triggers the release of various inflammatory mediators, including histamine, leukotrienes, cytokines, and prostaglandins. 2. **Airway Remodelling** Prolonged inflammation in asthma can lead to structural changes in the airways over time. These changes, known as airway remodelling, involve increased smooth muscle mass, thickening of the airway walls, and hypertrophy (enlargement) of the mucous glands. Airway remodelling contributes to the chronicity of asthma and can result in persistent airflow limitation. 3. **Bronchoconstriction** The inflammatory response in asthma causes the airway's smooth muscles to contract, leading to bronchoconstriction. This narrowing of the airways reduces airflow and causes symptoms such as wheezing, coughing, and shortness of breath. 4. **Mucus Production** The inflammation in asthma stimulates the production of excess mucus by the goblet cells in the airway epithelium. The increased mucus production further narrows the airways and contributes to airway obstruction. 5. **Airway Hyperresponsiveness** Asthma is characterized by increased sensitivity and hyperresponsiveness of the airways to various triggers. This means that the airways overreact to stimuli that would not typically cause a significant response in individuals without asthma. The exaggerated response leads to excessive bronchoconstriction and symptoms even in the presence of relatively minor triggers. 6. **Impaired Exhalation** Due he narrowed airways and increased resistance to airflow, individuals with asthma may have trouble exhaling fully. This results in air trapping increased residual volume, and decreased expiratory airflow rates, leading to the characteristic wheezing sound during exhalation.

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