Respiratory Disorders (MBS 214) PDF

Pathophysiology (2) (MBS 214) Respiratory Disorders Textbook; Pathophysiology for the Health Professions, 4th edition, 2011 Chapter 19 (p.323-375)  Respiratory Disorders Chapter outline:-  Review of Normal Structures in the Respiratory System  Infec...

Pathophysiology (2) (MBS 214) Respiratory Disorders Textbook; Pathophysiology for the Health Professions, 4th edition, 2011 Chapter 19 (p.323-375)  Respiratory Disorders Chapter outline:-  Review of Normal Structures in the Respiratory System  Infectious Diseases  Obstructive Lung Diseases  Vascular Disorders  Expansion Disorders  Lecture 3 Respiratory Disorders Learning objectives: After studying this chapter ,the student is expected to: Describe the common upper respiratory tract infections Compare the different types of pneumonia. Differentiate the effects of primary from secondary tuberculosis. Describe the pathophysiology and complications of cystic fibrosis. Describe the etiology and pathophysiology of bronchogenic carcinoma Compare the types of asthma and describe the pathophysiology and manifestations of an acute attack Compare emphysema and chronic bronchitis Describe the causes of pulmonary edema and explain how it affects oxygen levels. Compare the effects of small, moderate, and large-sized pulmonary emboli. Describe the causes of atelectasis and the resulting effects on ventilation and oxygen levels Explain the effects of pleural effusion on ventilation. Compare the types of pneumothorax. Explain how a flail chest injury affects ventilation, oxygen levels, and circulation. Describe the pathophysiology and signs of infant respiratory distress syndrome. Describe the possible causes of adult respiratory distress syndrome and the pathophysiology. Describe the etiology and changes in blood gases with acute respiratory failure. Explain the cause of sleep apnea and describe the effects and complications of this disorder.  REVIEW OF NORMAL STRUCTURES IN THE RESPIRATORY SYSTEM The respiratory system consists of two anatomic areas. The upper respiratory tract is made up of the passageways that conduct air between the atmosphere and the lungs, I The lower respiratory tract consists of the trachea, bronchial tree, and the lungs, where gas exchange takes place Lungs are covered by pleura In addition, the pulmonary circulation, the muscles required for ventilation, and the nervous system, which plays a role in controlling respiratory function, are integral to the function of the respiratory system. Respiratory disorders may result from airway obstructions, alveolar damage, reduced lung expansion, or interference with pulmonary blood flow.  Mechanism of Breathing Inspiration Expiration o a The external intercostal muscles contract while the The internal intercostal muscles contract while the internal intercostal muscles external intercostal muscles relax. relax. Elevate the ribs  Lower the ribs   Tidal volume (TV): The amount Inspiratory and expiratory reserve volume (IRV Volumes of Air Exchanged of air that normally enters & & ERV): The difference between normal amounts exits with each breath. and the maximum effort amounts of air moved. during Ventilation 28 Vital capacity (VC): The amount of air that Residual volume (RV): The amount of moves in plus the amount that moves out air that stays in the lungs even after a with maximum effort (Deep breathing). very deep exhalation. 5,800 maximum inspiratory expiration reserve 4,800 volume maximum inspiration Average Lung Volume (ml) vital 3,600 capacity total 2,900 Lung capacity tidal volume 2,400 expiratory reserve volume 1,200 Dead air space: Volume residual volume residual volume of air that remains in to VC = IRV+TV+ERV the airways SEE and is not Total 0 lung capacity (TLC) = VC+RV used for gas exchange.  Regulation of Breathing i Conscious control in Nervous Control the cortex can modify A respiratory center in the brain automatic regulatory establishes a regular pattern of control but cannot breathing (12 – 20 / min). override it completely. Receptor cells near the respiratory Medulla oblongata yea center respond to changes in CSF H+ caused by increases in arterial CO2. Nerve signals to and from (CO2 + H2O  H2CO3  H+ + HCO3- the respiratory center ) Chemical Control Carotid Receptor cells in the carotid bodies and aortic bodies respond to Aortic large decreases in arterial O2. bodies Intercostal The rate and depth of normal muscles breathing is determined by the need to get rid of CO2 rather than the need to obtain O2 Diaphragm Gas Exchanges in the Body O2 must be supplied to all the cells, and CO2 must be removed from the body during gas exchange. The principles of diffusion govern whether O2 or CO2 enters or leaves the blood in the lungs and in the tissues. The amount of pressure each gas exerts is called its partial pressure, symbolized as Po2 & Pco2.  3 External Respiration o Exchange of gases between air in alveoli and blood in pulmonary capillaries Blood in pulmonary capillaries has a giant higher Pco2 than atmospheric air. CO2 8 diffuses out of the plasma into lungs. Most of CO2 is carried in plasma as HCO3-. H+ + HCO3- → H2CO3 → H2O + CO2 carbonic anhydrase Blood in the pulmonary capillaries is low in oxygen, and alveolar air contain a f higher Po2. O2 diffuses into plasma and then into red blood cells in the lungs. 0 Hemoglobin (Hb) takes up this oxygen and becomes oxyhemoglobin (HbO₂) Hb + O2 → HbO2  Internal 3 Exchange of gases between the blood in systemic capillaries and the tissue cells. Respiration G Oxygen diffuses out of the blood into the tissues because the Po2 of tissue HbO2 → Hb + O2 fluid is lower than that of blood. 5m c Carbon dioxide diffuses into blood from tissues because the Pco2 of tissue fluid is higher than that of blood. H2O + CO2 → H2CO3 → H+ + HCO3-  Small amount of CO2 is taken up by hemoglobin, forming carbaminohemoglobin 8  Most CO2 is transported in plasma as HCO3-. to (HbCO2).  The globin of Hb combines with H+ excess becomes HHb (reduced Hb).  GENERAL MANIFESTATIONS OF RESPIRATORY DISEASE o o 1. Sneezing: a reflex response to irritation in the upper respiratory tract 2. Coughing :expel air from the lungs with a sudden sharp o sound. 0 000 3. Sputum or mucoid discharge; thin, clear, and colorless or cream color. 4. Breathing pattern: The normal rate (eupnea) is 10 to 18 O inspirations per minute, regular and effortless. 5. Breath sounds may be abnormal (Rales; light bubbly and Rhonchi; harsh) or absent. 6. Dyspnea is a subjective feeling of discomfort that occurs when a person feels unable to inhale enough air (shortness of breath).  GENERAL MANIFESTATIONS OF RESPIRATORY DISEASE 0 7. Cyanosis is the bluish coloring of the skin and mucous membranes. 8. Pleural pain: a cyclic pain that increases as the inflammed membrane is stretched with inspiration or coughing. 9. Friction rub may be heard; a soft sound produced as the rough membranes f move against9 each other. 10. Clubbed fingers and sometimes toes; enlargement of the tips resembles a drumstick-like shape, result from chronic hypoxia. 11. Changes in arterial blood gases (ABGs): Hypoxemia refers to inadequate oxygen in the blood (PO2). Hypoxia, or inadequate oxygen supply to the cells https://slideplayer.com/slide/6922348/  DIAGNOSTIC TESTS Spirometry-pulmonary function testing (PFT) is used to test pulmonary volumes and airflow (volume vs. times). Arterial blood gas determinations are used to check oxygen, carbon dioxide, and bicarbonate levels as well as serum pH. Oximeters measure O2 saturation. A normal healthy person should be able to achieve normal blood oxygen saturation levels (SpO2) of 94% to 99%. Exercise tolerance testing is useful in patients with chronic pulmonary disease for diagnosis and monitoring of the patient’s progress.  DIAGNOSTIC TESTS Radiography may be helpful in evaluating tumors or infections such as pneumonia or tuberculosis. Bronchoscopy may be used in performing a biopsy or in checking for the site of a lesion or bleeding. Culture and sensitivity tests on exudates from the upper respiratory tract or sputum specimens can identify pathogens and assist in determining the appropriate therapy.  Spirometry Spirometry is a type of pulmonary function test (PFT), a noninvasive procedure that provides important information about how well the lungs are working. Spirometry measures your airflow, measure how much air you inhale, how much air you exhale and how quickly you exhale. Spirometry is used to diagnose chronic lung diseases. Also to monitor current treatment plan. Spirometry indicates whether or not there is airway obstruction or airway restriction  Respiratory disorders  Infectious Diseases  Obstructive Lung Diseases  Restrictive Lung Disorders  Vascular Disorders  Expansion Disorders 1- INFECTIOUS RESPIRATORY DISORDERS A- UPPER RESPIRATORY DISORDERS B- LOWER RESPIRATORY DISORDERS  1- INFECTIOUS DISEASES UPPER RESPIRATORY TRACT So INFECTIONS – Common Cold (Infectious Rhinitis) viral infection – Sinusitis, bacterial infection secondary to a cold or a an allergy – Laryngotracheobronchitis (Croup)-common viral infection 00 – Epiglottitis – Influenza (Flu) https://www.youtube.com/watch?v=jKrpj777YnY  1- INFECTIOUS DISEASES LOWER RESPIRATORY TRACT INFECTIONS – Bronchiolitis (RSV Infection) respiratory syncytial virus , a myxovirus – Pneumonia; Lobar pneumonia Bronchopneumonia Primary atypical pneumonia Pneumocystis carinii pneumonia (PCP) – Severe Acute Respiratory Syndrome – Tuberculosis – Histoplasmosis, a fungal infection – Anthrax is a bacterial infection of the skin, respiratory tract or GI tract of humans and cattle  1- INFECTIOUS DISEASES Viruses cause both upperE and lower respiratory tract infections, including the common cold, laryngotracheobronchitis (croup), influenza, bronchiolitis, and primary atypical pneumonia. Describe the common complications of viral respiratory infection? astridays  Common childhood respiratory infections n Para-infleunza virus 88 Respiratory syncytial virus,a myxovirus. EEE leaning forward, hands on knees https://www.youtube.com/watch?v =GZe_RHLbQWY Stridor; noisy breathing,https://www.youtube.com/watch?v=5DN7xCleoyQ Drooling; flow of saliva outside the mouth https://www.youtube.com/watch?v=N91TUXfTT_E Hoarse: vocal cords impaired with affection of the sound  Pneumonia Pneumonia is a type of lung infection that inflames the air sacs in one or both lungs, which impairs oxygen diffusion when exudate fills the alveoli or interstitial tissue in the lungs. Pneumonia is frequently but not always due to infection. The infection may be bacterial, viral, fungal, or parasitic. It can also be E caused by inhalation of certain chemicals that irritate the lung tissue (aspiration pneumonia). 00 Symptoms may include fever, chills, cough with sputum production, chest pain, and shortness of breath. Treatment includes antibiotics. Prognosis :Pneumonia can range in seriousness from mild to life- threatening. Those most at risk of severe infection from pneumonia include smokers, people with heart or lung disease, infants and young children, adults age 65 and older, and people with chronic medical conditions or weakened immune systems  Classification (types)of the pneumonias (lung) Diffuse through out lung ,bacteria without cell wall D (Dry cough) Rales: discontinuous crackling SOUND heard on auscultation, primarily during inhalation , associated with serous secretions. Rhonchi are deeper and harsher sounds resulting from thicker mucus. https://www.easyauscultation.com/rales Interstitial Pneumonia (Atypical) a  9 Severe Acute Respiratory Syndrome(SARS)- Respiratory distress syndrome c SARS-associated coronavirus is the causative agent which affect the alveolar epithelium, causing failure of gas exchange 0 It is transmitted by respiratory droplets during close contacts Pathophysiology ; – Flu like symptoms are present for 3 to 7 days followed several days later by a dry cough and marked dyspnea. – By day 7,chest radiographs indicate spreading patchy areas of interstitial congestion and SEE severe hypoxia – There may be thrombocytopenia,lymphpenia, and elevated liver enzymes(due to viral damage) – The final stage: is severe respiratory distress  Severe Acute Respiratory Syndrome(SARS) C Signs and symptoms generate Stage1; fever, headache, myalgia, diarrhea Stage2; nonproductive cough, severe dyspnea, hypoxia more specific Stage3; severe hypoxia, respiratory and metabolic acidosis SARSI Medications included the antiviral ribavirin and the glucocorticoid methylprednisolone cod  Pneumocystis carinii pneumonia (PCP) It is an atypical pneumonia, IE that occurs as an opportunistic infection Occurs most commonly in immunosuppressed individuals (AIDS) It also causes pneumonia in premature infants. The etiological agent is a fungus that is inhaled and attaches to alveolar IEcells, causing necrosis and diffuse interstitial inflammation Onset is marked by dyspnea and a nonproductive cough https://www.youtube.com/watch?v=cuZb539SaaY  Tuberculosis The causative organism is Mycobacterium tuberculosis which is acid fast, aerobic, slow- 8 growing bacillus that is resistant to dryness and many disinfectants Why it is difficult for host defensive cells to eradicate TB bacilli? 0 – The fatty cell wall of the organisms protect against I digestion and destruction by defensive individual cells and antibiotics Who are at high risk of contracting TB? – Those whose resistance are lowered 8 because of immunodeficiency (AIDS), malnutrition, alcoholism , or chronic disease.  Pathophysiology of Tuberculosis (Development F of tuberculosis) An airborne disease Inhalation or ingestion of the microorganism result in inflammatory reaction at the site of infection (lung, tonsils or small intestine) Depend on the immunity of the individual , there are two stages in the pathogenesis of tuberculosis— Primary infection (TB infection) and Secondary infection or reinfection (TB disease) http://www.fw-ac-deptofhealth.com/images/tbanim2.gif  Tuberculosis Primary infection: Pathogens are engulfed by macrophages and causes local inflammatory reaction. A granuloma (Ghon tubercle) is formed at the site of Fi inflammation (macrophages containing bacilli surrounded by T lymphocytes). Minimal caseation necrosis may develops in the center of the tubercle, walled off by fibrous tissue and usually become calcified. Ghon tubercle o is the pathognomonic feature for primary TB infection. Some macrophages containing bacilli migrate to the regional lymph nodes, activating a type IV hypersensitivity response (delayed cell mediated response) with enlargement of the lymph nodes. Ghon complex : is formed of Ghon tubercle with tuberculous lymphadenitis.  Mycobacterium tuberculosis (Mtb) induces an immune response in the lungs of a host that can lead to formation of a cellular aggregate called a granuloma in which the Mtb can remain dormant in the condition of latent tuberculosis (TB). Direct and indirect upregulation of matrix metalloproteinase (MMP), which is stimulated by the Mtb in infected macrophages in the granuloma and denoted by a dashed arrow, degrades the collagen exterior of the granuloma, triggering leakage of extracellular bacteria (B E ) and formation of a necrotic leaking granuloma called a TB cavity.  Tuberculosis It is asymptomatic In case of good immunity—healing by fibrosis and calcification occur In case of moderate immunity---patient pass to secondary TB I In case of very low immunity---Miliary tuberculosis  Tuberculosis Secondary infection to a It often arises years after primary infection due to decreased host resistance Increase of the number and size of the tubercle with development of extensive caseation (necrosis, cavitation and tissue destruction)occur. 0_ Spread ; – Direct to surrounding tissue or – To lymphatic , – To blood (Miliary TB), Rapidly progressive form in which multiple granulomas affect large areas of the lungs with rapid dissemination via the bloodstream to other organs result in systemic infection with subnormal temperature It is symptomatic, has insidious onset with vague symptoms of : – Anorexia, malaise, fatigue and weight loss (toxemia). – Afternoon low-grade fever and night sweats. – Prolonged and increasingly severe cough and productive, purulent sputum, containing blood. E 0  Tuberculosis How diagnosis of active TB (infectious) is confirmed? – Chest x-ray – Acid staining of sputum specimen – Sputum culture no AB forms What is a Mantoux test? What is a positive due to TB Mantoux test indicate? body goesthrough – Mantoux test is the tuberculin test. type 4 Mtivity – A positive skin test does not mean the person active TB. It means that there has been adequate exposure to cause a hypersensitivity reaction.(so BCG is contraindicated?)  Treatment of Tuberculosis Medications: antituberculous drugs Multiple drugs required to prevent development of resistant strains. Duration of treatment; months to 1 year or possibly longer, depending upon the health of the individual. 0 An individual will become noncontagious when sputum is negative for microbes, usually 1 to 2 months. Drugs are prescribed for a longer period to ensure eradication of the infection. iii Prophylactic treatment is essential for: Skin test has converted from negative to positive within the last 2 years Who have radiographic changes consistent with TB Who in close contact with individual with active TB Immunosuppressed individuals People with HIV or with hematological cancer Measures must be taken by health care professional to protect himself; Have regular skin tests Regular chest radiographs Maintain host resistance (adequate rest and nutrition) 2- OBSTRUCTIVE LUNG DISEASES CYSTIC FIBROSIS LUNG CANCER ASPIRATION OBSTRUCTIVE SLEEP APNEA ASTHMA CHRONIC OBSTRUCTIVE PULMONARY DISEASE – EMPHYSEMA – CHRONIC BRONCHITIS – BRONCHIECTASIS  Cystic fibrosis Cystic fibrosis is a recessive inherited disorder, common in children – It is a genetic disorder involving a defect in chloride ion transport in cell membranes This defect in the exocrine glands causes abnormally thick mucus secretions. The primary effects of cystic fibrosis are seen in the lungs and the pancreas, where the sticky mucus obstructs the passages  Cystic fibrosis 0000 0 Right sided heart failure from high 0 0 blood pressure in the arteries of the lungs 88 Fatty stools