PCM Fall Exam
Notes on Asthma, COPD, Cystic Fibrosis, Community-Acquired Pneumonia, Pulmonary Embolism, Mitral Stenosis
Asthma
Essentials of Diagnosis:
· Episodic or chronic symptoms of airflow obstruction: breathlessness, cough, wheezing, and chest tightness.
· Symptoms frequently worse at night or in the early morning.
· Prolonged expiration and diffuse wheezes on physical examination.
· Limitation of airflow on pulmonary function testing or positive bronchoprovocation challenge.
· Complete or partial reversibility of airflow obstruction, either spontaneously or following bronchodilator therapy.
General Considerations:
· Common disease affecting 5% of population.
· Men and women equally affected.
· 470,000 hospital admissions and 5,000 deaths in USA attributable to asthma.
· Hospitalization and death rates highest among blacks aged 15 – 24 years.
· Prevalence, hospitalizations, and fatal asthma have all increased in USA over the past 20 years.
Definitions and Pathogenesis:
· Asthma is a chronic inflammatory disorder of the airways.
· Airway inflammation underlies disease chronicity and contributes to airway hyperresponsiveness, airflow limitation, and to respiratory symptoms.
· Genetic predispostion recognized, related to atopy.
· Both specific and nonspecific precipitants exist.
Clinical Findings:
· Episodic wheezing, difficulty breathing, chest tightness, cough.
· Frequency of symptoms is highly variable.
· Symptoms may occur spontaneously or be precipitated or exacerbated by many different triggers.
· Asthma symptoms are frequently worse at night.
· Nasal mucosal swelling, increased nasal secretions, and nasal polyps are often seen in patients with allergic asthma.
· Eczema, atopic dermatitis, or other manifestations of allergic skin disorders may also be present.
· Hunched shoulders and use of accessory muscles of respiration suggest increased work of breathing.
· Chest examination may be normal between exacerbations in patients with mild asthma.
· Wheezing during normal breathing or prolonged forced expiration correlates well with the presence of airflow obstruction.
· During severe asthma wheezing may disappear, and the only diagnostic clue on auscultation may be globally reduced breath sounds with prolonged expiration.
· The evaluation for asthma should included spirometry (FEV1, FVC, FEV1/FVC) before and after the administration of a short-acting bronchodilator.
Complications:
· Exhaustion, dehydration, airway infection, cor pulmonale, tussive syncope.
· Rare pneumothorax.
· Hypercapnic and hypoxic respiratory failure in severe disease.
Differential Diagnosis:
· Upper airway disorders: vocal cord paralysis, vocal cord dysfunction syndrome, foreign body aspiration, laryngotracheal masses, tracheal narrowing, tracheomalacia, airway edema.
· Lower airway disorders: COPD, bronchiectasis, allergic brochopulmonary mycosis, cystic fibrosis, eosinophilic pneumonia, bronchiolitis obliterans.
· Systemic vasculitides: Churg-Strauss syndrome, others with pulmonary component.
· Psychiatric: conversion disorders, Munchausen syndrome, malingering.
Classification:
· Mild intermittent: Symptoms ≤ 2 times a week with normal function between exacerbations. Nighttime symptoms ≤ 2 times a month.
· Mild persistent: Symptoms > 2 times per week but < 1 time a day. Nighttime symptoms > 2 times a month.
· Moderate persistent: Daily symptoms and/or daily use of inhaled short-acting β2-agonist. Exacerbations affect activity. Nighttime symptoms > 1 time a week.
· Severe persistent: Continual symptoms. Limited physical activity. Frequent exacerbations and nighttime symptoms.
Treatment:
· Corticosteroids: most potent and consistently effective anti-inflammatory agents currently available. Inhaled agents used for long-term control and systemic agents used for prompt control of short-term exacerbations.
· Long-acting bronchodilators
· Short-acting bronchodilators: β2-agonists and others.
Approach to Treatment:
· Principal goals: correction of hypoxemia, reversal of airflow obstruction, reduction of the likelihood of recurrence of obstruction.
· Periodic assessments and ongoing monitoring of asthma are essential to determine if the goals of therapy are being met.
COPD
Essentials of Diagnosis:
· History of cigarette smoking.
· Chronic cough and sputum production (in chronic bronchitis) and dyspnea (in emphysema).
· Rhonchi, decreased intensity of breath sounds, and prolonged expiration on physical examination.
· Airflow limitation on pulmonary function testing.
General Considerations:
· COPD is a disease state characterized by the presence of airflow obstruction due to chronic bronchitis or emphysema; the airflow obstruction is generally progressive, may be accompanied by airway hyperreactivity, and may be partially reversible.
· Most patients with COPD have features of both emphysema and chronic bronchitis.
· Chronic bronchitis: characterized by excessive secretion of bronchial mucus and is manifested by productive cough for 3 months or more in at least 2 consecutive years in the absence of any other disease that might account for this symptom.
· Emphysema: abnormal, permanent enlargement of air spaces distal to the terminal bronchiole, with destruction of their walls and without obvious fibrosis.
· Cigarette smoking is clearly the most important cause of COPD.
Clinical Findings:
· Patients with COPD characteristically present in the fifth or sixth decade of life complaining of excessive cough, sputum production, and shortness of breath.
· Symptoms have often been present for 10 years or more.
· Dyspnea is often noted initially only on heavy exertion, but this exacerbates as the condition progresses.
· Clinical findings may be completely absent early in the course of COPD.
· “Pink puffers” = emphysema predominant.
· “Blue bloaters” = bronchitis predominant.
Differential Diagnosis:
· Clinical, imaging, and laboratory findings should enable the clinician to distinguish COPD from other obstructive pulmonary disorders.
· These include: bronchial asthma, bronchiectasis, cystic fibrosis, bronchopulmonary mycosis, central airflow obstruction.
Complications:
· Stable COPD: acute bronchitis, pneumonia, pulmonary thromboembolism, concomitant left ventricular failure.
· Advanced COPD: pulmonary hypertension, cor pulmonale, chronic respiratory failure.
· Spontaneous pneumothorax and hemoptysis are also possible.
Prevention:
· Elimination of chronic exposure to tobacco smoke.
· Smoking cessation.
Treatment:
· Smoking cessation.
· Oxygen therapy.
· Bronchodilators.
· Antibiotics for treating acute exacerbations.
· Lung transplantation.
Prognosis:
· Poor.
· Median survival time of patients with severe COPD is about 4 years.
· Degree of pulmonary dysfunction at the time the patient is first seen is the most important predictor of survival.
Cystic Fibrosis
Essentials of Diagnosis:
· Chronic or recurrent cough, sputum production, dyspnea, and wheezing.
· Recurrent infections or chronic colonization of the airways with nontypeable Haemophilus influenzae, mucoid and nonmucoid Pseudomonas aeruginosa, Staphylococcus aureus, or Burkholderia cepacia.
· Pancreatic insufficiency, recurrent pancreatitis, distal intestinal obstruction syndrome, chronic hepatic disease, nutritional deficiencies, or male urogenital abnormalities.
· Bronchiectasis and scarring on chest radiographs.
· Airflow obstruction on spirometry.
· Sweat chloride concentration above 60 meq/L on two occasions or mutations in genes known to cause cystic fibrosis.
General Considerations:
· Most common cause of severe chronic lung disease in young adults.
· Most common fatal hereditary disorder of Caucasians in the USA.
· Autosomal recessive disorder affecting about one in 3200 Caucasians; one in 25 is a carrier.
· Caused by abnormalities in CFTR protein that results in altered chloride transport and water flux across the apical surface of epithelial cells.
· Mutation referred to as ΔF508 accounts for 60% of CF cases.
Clinical Findings:
· CF should be suspected in a young adult presenting with a history or chronic lung disease (especially bronchiectasis), pancreatitis, or infertility.
· Cough, sputum production, decrease exercise tolerance, and recurrent hemoptysis are typical complaints.
· Patients also often complain of facial (sinus) pain or pressure and purulent nasal discharge.
· Steatorrhea, diarrhea, and abdominal pain are also common.
· Digital clubbing, increase anteroposterior chest diameter, hyperresonance to percussion, and apical crackles are noted on physical examination.
· Sinus tenderness, purulent nasal secretions, and nasal polyps may also be seen.
· Chloride sweat test used for diagnosis.
Treatment:
· Early recognition and comprehensive multidisciplinary therapy improve symptom control and the chances or survival and amelioration of symptoms.
· Tx includes: clearance and reduction of lower airway secretions, reversal of bronchoconstriction, treatment of respiratory tract infections and airway bacterial burden, pancreatic enzyme replacement, nutritional and psychosocial support.
· Lung transplantation for advanced cystic fibrosis.
Prognosis:
· Median survival age is now 31 years.
· Death occurs from pulmonary complications or as a result of terminal chronic respiratory failure and cor pulmonale.
Community-Acquired Pneumonia
Essentials of Diagnosis:
· Symptoms and signs of an acute lung infection: fever or hypothermia, cough with or without sputum, dyspnea, chest discomfort, sweats or rigors.
· Bronchial breath sound or rales are frequent auscultatory findings.
· Parenchymal infiltrate on chest radiographs.
· Occurs outside of the hospital or less than 48 hours after admission in a patient who is not hospitalized or residing in a long-term facility for more than 14 days before the onset of symptoms.
General Considerations:
· Approximately 2 – 3 million cases diagnosed each year in the USA.
· Most deadly infectious disease and sixth leading cause of death in USA.
· Mortality and morbidity risk factors include: advanced age, alcoholism, comorbid medical conditions, altered mental status, respiratory rate ≥ 30 breaths/min, hypotension, and BUN > 30 mg/dL.
Definitions and Pathogenesis:
· Pulmonary defense mechanisms (cough reflex, mucociliary clearance system, immune responses) normally prevent the development of lower respiratory tract infections following aspiration of oropharyngeal secretions containing bacteria or inhalation of infected aerosols.
· Community-acquired pneumonia occurs when there is a defect in one or more of the normal host defense mechanisms or when the infectious pathogen overwhelms the host.
· Streptococcus pneumoniae is the most common bacterial pathogen (2/3 of bacterial isolates).
· Other common bacterial pathogens include Haemophilus influenzae, Mycoplasma pneumoniae, Chlamydia pneumoniae, Staphylococcus aureus, Neisseria meningitidis, Moraxella catarrhalis, Klebsiella pneumoniae, other gram-negative rods, and legionella species.
· Viral causes of community-acquired pneumonia include influenza virus, respiratory syncytial virus, adenovirus, and parainfluenza virus.
Clinical Findings:
· Acute or subacute onset of fever, cough with or without sputum production, and dyspnea.
· Other common symptoms include rigors, sweats, chills, chest discomfort, pleurisy, fatigue, myalgias, anorexia, headache, and abdominal pain.
· Common physical findings include fever or hypothermia, tachypnea, tachycardia, and mild arterial oxygen desaturation.
· Chest examination is often remarkable for altered breath sounds and rales.
· Dullness to percussion may be present if a parapneumonic pleural effusion is present.
· Differential diagnosis includes upper respiratory tract infections, reactive airway diseases, congestive heart failure, bronchiolitis obliterans organizing pneumonia, lung cancer, pulmonary vasculitis, pulmonary thromboembolic disease, and atelectasis.
· Sputum gram stains are often used to help identify causative organisms.
· Chest radiography may confirm the diagnosis and detect associate lung diseases.
Treatment:
· Antimicrobial therapy should be indicated promptly after the diagnosis of pneumonia is established and appropriate specimens are obtained.
· Decisions regarding hospitalization should be based on prognostic criteria.
· Local resistance pattern data should guide empirical antibiotic therapy.
Prevention:
· Polyvalent pneumococcal vaccine has the potential to prevent or lessen the severity of the majority of pneumococcal infections in immunocompetent patients.
· Influenza vaccine is also an important prevention technique.
Pulmonary Embolism
Essentials of Diagnosis:
· Predisposition to venous thrombosis, usually of the lower extremities.
· Usually one of the following: dyspnea, chest pain, hemoptysis, syncope.
· Tachypnea and a widened alveolar-arterial PO2 difference.
· Characteristic defects on ventilation-perfusion lung scan, spiral CT scan of the chest, or pulmonary angiogram.
General Considerations:
· Common, serious, and potentially fatal complication of thrombus formation within the deep venous circulation.
· Estimated to cause 50,000 deaths each year in the USA and is the third leading cause of death among hospitalized patients.
· Management demands a vigilant systematic approach to diagnosis and an understanding of risk factors so that appropriate preventative therapy can be given.
· Many substances can embolize to the pulmonary circulation, and deep venous thrombi of the calf muscle circulation are the most common.
· Pulmonary embolism and deep venous thrombosis are two manifestations of the same disease.
· Risk factors include: venous stasis, injury to the vessel wall, and hypercoaguability.
Clinical Findings:
· Clinical diagnosis is notoriously difficult for two reasons: (1) the clinical findings depends on both the size of the embolus and the patient’s preexisting cardiopulmonary status; (2) common symptoms and signs of pulmonary emboli are not specific to this disorder.
· The most sensitive findings are dyspnea, pain on inspiration, and tachypnea.
· Other common findings are cough, leg pain, hemoptysis, crackles, tachycardia, and abnormal heart sounds.
· ECG abnormalities are found in 70% of PE patients.
· D-dimer testing is extremely sensitive, such that the absence of D-dimer using ELISA provides strong evidence against PE.
· Chest radiograph and perfusion scan are used together to evaluate PE.
· Spiral CT, MRI, and venous thrombosis studies can also be used.
· Pulmonary angiography remains the reference standard for the diagnosis of PE.
Prevention:
· Prophylactic intervention is extremely important, but remains underutilized.
· Mechanical devices such as compression stockings and pneumatic compression devices are utilized.
· Heparin therapy is also utilized in the hospital setting.
Treatment:
· Anticoagulation with heparin is a form of secondary prevention.
· Thrombolytic therapy for patients with established PE.
Mitral Stenosis
Essentials of Diagnosis:
· Dyspnea, orthopnea, and paroxysmal nocturnal dyspnea.
· Symptoms often precipitated by onset of atrial fibrillation or pregnancy.
· Prominent mitral first sound, opening snap (usually), and apical diastolic crescendo rumble.
· ECG shows left atrial abnormality and, commonly, atrial fibrillation. Echo-Doppler confirms diagnosis and quantifies severity.
General Considerations:
· Nearly all patients with mitral stenosis have underlying rheumatic heart disease, though a history of rheumatic fever is often absent.
Clinical Findings:
· Characteristic finding of mitral stenosis is a localized middiastolic murmur low in pitch whose duration varies with the severity of the stenosis and the heart rate.