Respiratory Disease: Asthma, COPD & TB PDF

Respiratory disease Asthma, COPD and TB Dr Ali Adnan  What is Asthma? Asthma may be defined as a chronic inflammatory disorder of the airways secondary to type 1 hypersensitivity. The symptoms: reversible bronchospasm resulting...

Respiratory disease Asthma, COPD and TB Dr Ali Adnan  What is Asthma? Asthma may be defined as a chronic inflammatory disorder of the airways secondary to type 1 hypersensitivity. The symptoms: reversible bronchospasm resulting in airway obstruction. Signs includes dyspnea, coughing, and wheezing.  EPIDEMIOLOGY It affects over 10% of children and around 5-10% of adults, with the prevalence of asthma increasing. Asthma may present at any age although it typically develops in childhood. For many of these children their symptoms improve or resolve with age, and patients often report 'growing out' of their childhood asthma  ETIOLOGY ‣ personal or family history of topical allergy ‣ prenatal factors: maternal smoking, viral infection during pregnancy (especially RSV) ‣ low birth weight ‣ not being breastfed ‣ maternal smoking around child ‣ exposure to high concentrations of allergens (e.g. house dust mite) ‣ air pollution  PATHOPHYSIOLOGY AND COMPLICATIONS ‣ In asthma, obstruction of airflow occurs as the result of bronchial smooth muscle spasm, inflammation of bronchial mucosa, mucus hyper secretion, and sputum plugging. ‣ The most striking macroscopic finding in the asthmatic lung is occlusion of the bronchi and bronchioles by thick, tenacious mucous plugs. ‣ Histologic findings are those of inflammation and airway remodelling, including (1) thickening of the basement membrane (from collagen deposition) of the bronchial epithelium, (2) oedema, (3) mucous gland hypertrophy and goblet cell hyperplasia, (4) hypertrophy of the bronchial wall muscle, (5) accumulation of mast cell and inflammatory cell infiltrate, (6) epithelial cell damage and detachment, and (7) blood vessel proliferation and dilation. These changes contribute to decreased diameter of the airway, increased airway resistance, and difficulty in expiration. ‣ Asthma is relatively benign in terms of morbidity. Most patients can expect a reasonably good prognosis, especially those in whom the disease develops during childhood. In many young children, the condition resolves spontaneously after puberty. ‣ In a small percentage of patients, both young and old, the condition can progress to COPD, and respiratory failure, or status asthmaticus, the most serious manifestation of asthma, may occur.  CLINICAL PRESENTATION Symptoms cough: often worse at night dyspnoea 'wheeze', 'chest tightness' Signs expiratory wheeze on auscultation reduced peak expiratory flow rate (PEFR)  LABORATORY AND DIAGNOSTIC FINDINGS Recognising signs and symptoms is crucial in asthma diagnosis since laboratory tests lack specificity, and no single test is definitive. Commonly ordered tests include the 6-minute walk test. spirometry (pre and post bronchodilator). chest radiographs (for hyperinflation detection). skin testing (for allergens), bronchial provocation tests (histamine or methacholine chloride challenge). sputum smear examination (for cell counts). arterial blood gas determination. ELISA (enzyme-linked immunosorbent assay) for measuring environmental allergen exposure. Fractional exhaled nitric oxide determination is a noninvasive test aiding in asthma diagnosis and management.  MEDICAL MANAGEMENT ‣ The majority of patients manage their asthma through the use of inhalers, enabling localised delivery of medications to the airways. ‣ Treatment strategies also involve addressing contributing factors like smoking cessation and managing concurrent conditions such as rhino sinusitis and obesity, which can complicate asthma management. ‣ To monitor respiratory function at home, cost-effective peak expiratory flow meters should be regularly used, and daily readings recorded in journals. ‣ For individuals with known allergies, emphasising the importance of allergen avoidance is crucial in preventing asthma attacks. ‣ The choice of anti-asthmatic drugs depends on the type and severity of asthma, as well as whether the drug is intended for long-term control or immediate relief. Current guidelines advocate a gradual "stepwise" approach in managing asthma. Dental Management  What is TUBERCULOSIS? ‣ Tuberculosis is a significant infectious disease in humans caused by the communicable bacterium Mycobacterium tuberculosis. ‣ It poses a major global health challenge, leading to illness and fatalities across various populations worldwide. ‣ The transmission of the disease occurs through the inhalation of infected droplets, typically exhibiting a prolonged dormant period. ‣ Replication of M. tuberculosis triggers an inflammatory and granulomatous response in the host, resulting in the development of typical pulmonary and systemic symptoms.  EPIDEMIOLOGY Tuberculosis is globally prevalent, with an incidence of 9 to 10 million cases. According to the World Health Organization (WHO), approximately one-third of the global population, equivalent to 2 billion people, is estimated to be infected with the disease.  ETIOLOGY It is an aerobe Transmission of M. tuberculosis typically occurs through infected airborne droplets containing mucus or saliva, forcefully expelled from the lungs during activities such as coughing, sneezing, and talking. The extent of transmission is influenced by the quantity and size of the expelled droplets. Smaller droplets, which can float in the air, are easily inhaled, while larger droplets settle quickly to the ground. Another potential mode of transmission involves a patient coughing up infected sputum, leading to oral tissue inoculation and the initiation of TB- related oral lesions. The likelihood of contracting the disease is influenced by factors such as the number of inhaled organisms and the individual's level of immunocompetence.  PATHOPHYSIOLOGY AND COMPLICATIONS Tuberculosis can affect virtually any organ in the body, though the lungs are the most commonly affected site. The typical progression of primary pulmonary TB involves the inhalation of infected droplets, which are then carried into the alveoli. Within the alveoli, macrophages engulf the bacteria, leading to replication within these cells. Local spread of the infection occurs, involving regional (hilar) lymph nodes. Approximately 2 to 8 weeks after the onset of infection, a delayed hypersensitivity response to the bacteria develops, mediated by T (CD4+) helper lymphocytes. This immune response is evident in the conversion of tuberculin skin testing (using purified protein derivative [PPD], as discussed later) from negative to positive. Primary pulmonary TB is more commonly observed in infants and children, but cavitation is infrequent in these age groups. Children typically do not actively produce or expel sputum, instead often swallowing pulmonary secretions. In teenagers and adults, the expression of the disease differs somewhat, with less prominence of lymph node involvement and lymphohematogenous spread. However, cavitation is a common occurrence. Common reasons for relapse in tuberculosis (TB) include insufficient treatment of the initial infection and factors such as illness, use of immunosuppressive agents, immunodeficiency diseases (as seen in AIDS), and age.  CLINICAL PRESENTATION symptoms include cough, fatigue, malaise, loss of appetite, unexplained weight loss, night sweats, and fever. Fever typically occurs in the evening or at night and is accompanied by profuse sweating. Specific symptoms related to the affected organ vary. Persistent cough, often appearing late in the disease course, is a common symptom of pulmonary TB, especially in cases involving cavities. The produced sputum is typically scanty and mucoid, becoming purulent with advancing disease. Haemoptysis (blood in the sputum) is infrequent, occurring in around 20% of cases. Dyspnea is characteristic of advanced disease.  LABORATORY AND DIAGNOSTIC FINDINGS Laboratory tests aim to ascertain whether the patient has an active infection or latent tuberculosis infection (LTBI). Active infection is indicated by a positive acid-fast bacillus sputum smear, the presence of symptoms (such as cough, fever, weight loss, and night sweats), and observable characteristic changes in chest radiography. The conclusive diagnosis of tuberculosis relies on culture or direct molecular tests (e.g., nucleic acid amplification), which identify the presence of M. tuberculosis or other mycobacterial species in body fluids and tissues, typically obtained from sputum. MEDICAL MANAGEMENT DENTAL MANAGEMENT DENTAL MANAGEMENT  what is COPD? ‣ Chronic obstructive pulmonary disease (COPD) stands out as one of the most prevalent diagnoses encountered in medical practice, encompassing the older terms chronic bronchitis and emphysema. This condition is characterised by persistent airflow limitation from the lungs, which is not fully reversible. Chronic bronchitis is specifically defined as a state linked to the chronic inflammation of the bronchi, resulting in excessive production of tracheobronchial mucus (at the bronchial level). It manifests as a persistent cough with sputum for a minimum of 3 months in at least 2 consecutive years, ruling out other potential causes of productive chronic cough. ‣ On the other hand, emphysema is defined as a lasting enlargement of the air spaces in the lung, occurring distal to the terminal bronchioles. This enlargement is accompanied by the destruction of air space (alveolar) walls, and it occurs without evident fibrosis.  Etiology ‣ Globally, tobacco smoking is the primary cause of chronic obstructive pulmonary disease (COPD). Approximately 12.5% of current smokers, 9% of former smokers, and 8% of those exposed to passive smoke are affected by COPD. ‣ The risk of developing COPD is associated with the amount of cigarettes smoked per day and the duration of smoking, with a dose-related increase in risk. ‣ This observation suggests that genetic factors influencing the production of inflammatory mediators, such as cytokines, in response to smoke exposure play a crucial role. ‣ Apart from cigarette smoking, long-term exposure to occupational and environmental pollutants, as well as the absence or deficiency of α1-antitrypsin, are additional factors contributing to COPD. The enzyme α1-antitrypsin, produced in the liver, plays a role in neutralising neutrophil elastase. ‣ Some other causes are: coal, cadmium, grain, cement, cotton etc.  PATHOPHYSIOLOGY AND COMPLICATIONS ‣ Long-term exposure to cigarette smoke induces pathophysiological responses in the airways and lung tissue, particularly in chronic bronchitis, which affects both large and small airways. ‣ In the large airways, tobacco smoke and irritants lead to thickened bronchial walls, inflammatory cell infiltration, increased size of mucous glands, and goblet cell hyperplasia. In the small airways, obstruction is intensified by narrowing, scarring, heightened sputum production, mucous plugging, and the collapse of peripheral airways due to the loss of surfactant. This obstruction occurs during both inspiration and expiration. ‣ Chronic obstructive pulmonary disease (COPD) typically exhibits a progressive course marked by deterioration and periodic exacerbations unless early intervention is administered. The complications that arise vary based on the location of damage. ‣ Continued exposure to primary etiological factors, such as cigarette smoking and environmental pollutants, often leads to progressive dyspnea and hypercapnia. ‣ Recurrent pulmonary infections, especially with bronchitis, are common and managed with antibiotics. ‣ Pulmonary hypertension may develop, potentially leading to cor pulmonale (right-sided heart failure) without supplemental oxygen therapy. ‣ Patients with emphysema often present with enlarged air spaces, a higher incidence of thoracic bullae, and an increased risk of pneumothorax. ‣ COPD is also associated with sleep disturbances due to nocturnal hypoxemia, as well as coexisting conditions such as hypertension, ischaemic heart disease, arrhythmia risk, heart failure, myocardial infarction (MI), muscle wasting, and osteoporosis.  CLINICAL PRESENTATION The onset phase of chronic obstructive pulmonary disease (COPD) typically spans several years, often commencing after the age of 40. Symptoms manifest gradually, and many patients may not be aware of the developing condition. Key indicators include a chronic cough with intermittent or continuous sputum production, which can be either unproductive or productive, and vary in volume. Persistent and progressive dyspnea, especially worsening with exercise, is another significant symptom. Weight loss and decreased exercise capacity become apparent as the disease advances. Comorbid conditions associated with COPD encompass cardiovascular disease, respiratory infections, osteoporosis, and fractures. MEDICAL MANAGEMENT  DENTAL MANAGEMENT Identification: Patients with COPD often have a smoking history and may exhibit symptoms like cough, exertional dyspnea, or skin color changes. Dentists should promptly refer such patients to physicians for further evaluation. Dental health providers can contribute to preventing disease progression by encouraging smokers to quit. Providing information on smoking-related diseases and promoting healthy living can motivate patients to consider quitting. Various interventions, such as nicotine replacement and bupropion therapy, are available, and providers should assist patients in choosing the most suitable method. Risk Assessment:** Before initiating dental care, clinicians should evaluate the severity and control of the patient's respiratory disease. Unstable patients, displaying symptoms like shortness of breath, a productive cough, upper respiratory infection (URI), or oxygen saturation (O2 sat) below 91% (measured by pulse oximetry), should be referred for medical evaluation Airway and Breathing:** For stable patients (O2 sat >95%) with adequate breathing, efforts should focus on avoiding factors that could further depress respiration. Pulse oximetry monitoring is recommended. Humidified low-flow oxygen, typically at 2 to 3 L/min, may be provided if the oxygen saturation level is below 95%. If O2 sat is less than 91%, or there is dyspnea, rescheduling the appointment and making a medical referral is advised. **Capacity to Tolerate Care:** Dental care is generally suitable for patients with stages I to III COPD but should be avoided in those with stage IV (very severe) COPD. Patients with COPD often have coexisting hypertension, coronary heart disease, and an increased risk of cardiovascular events. If coexisting cardiovascular disease is present, stress reduction measures should be implemented, and vital sign monitoring is essential.