Diseases of the Respiratory System – Part 1

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A 33-year-old farmer complains of recurrent episodes of wheezing after working in a barn where hay is stored. On auscultation, there are bibasilar crackles and heart sounds are normal. His laboratory work is normal with no increase in eosinophils and the chest x-ray (CXR) reveals patchy lower lobe infiltrates. Which of the following is the most likely diagnosis?

Hypersensitivity pneumonitis is an inflammatory disorder of the lungs involving alveolar walls and terminal airways that is caused by repeated exposure to organic agents. In this example of “farmer’s lung,” the inhalation of antigens present in moldy hay such as thermophilic actinomyces or Aspergillus species are the causative agents. When exposure to moldy hay is stopped, symptoms and signs of farmer’s lung all tend to abate and complete recovery usually follows. In acute syndromes, the presentation is 4–8 hours after exposure. Symptoms include fever, chills, malaise, cough, and dyspnea without wheezing. The rate of disease depends on rainfall (which promotes fungal growth) and agricultural practices related to turning and stacking hay. In acute and subacute presentations, removing exposure to the antigen will result in complete recovery.

A 57-year-old man with a 40-pack-per-year history of smoking experiences symptoms of shortness of breath on exertion. He has bilateral wheezes on expiration and increased resonance to percussion of the chest. Pulmonary function tests confirm the diagnosis of chronic obstructive lung disease (COPD). Which of the following is the best definition of this condition?

COPD is defined as a disease state that is characterized by airflow limitation that is not fully reversible. Emphysema and chronic bronchitis are closely related, and the term COPD is often used to encompass both. Chronic bronchitis is a clinical syndrome defined as excessive tracheobronchial mucous production severe enough to cause productive cough for at least 3 months of the year for at least two consecutive years. Emphysema is defined as the distention of air spaces distal to the terminale bronchiole, with destruction of alveolar septa. It is primarily a histologic diagnosis. Smoking is the usual antecedent for COPD.

An agitated and nervous 24-year-old woman has had severe wheezing and shortness of breath for 2 days. After receiving oxygen, steroids, and salbutamol (Ventolin) in the emergency room, her breathing improves. She is still wheezing and now feels tremulous and anxious with a pulse of 110/min and respirations 30/min. Arterial blood gases on oxygen reveal a pH of 7.40, PO2 340 mm Hg, PCO2 40 mm Hg, and bicarbonate of 24 mEq/L. She is hospitalized for further treatment. Which of the following treatments or medications should be avoided in her?

Tranquilizers and sedatives should be avoided in prolonged asthma attacks. Bronchodilators, fluids, aminophylline, and steroids may be used. In acute situations, IV glucocorticoids are frequently used. Results of therapy should be monitored in an objective manner, with peak expiratory flow rates or FEV1. In acute asthmatic attacks, hypocarbia is usual on blood gas analysis. Normal or elevated PaCO2 is a bad sign and requires intensive monitoring and aggressive treatment.

A 29-year-old woman has a long history of mild asthma. She now has a flare and experiences recurrent episodes of bronchial obstruction, fever, malaise, and expectoration of brownish mucous plugs. On examination, there is bilateral wheezing. Infection is suspected and a CXR reveals upper lobe pulmonary infiltrates. The eosinophil count is 2000/mL, and serum precipitating antibodies to Aspergillus are positive. Which of the following is the most appropriate next step in management?

Allergic bronchopulmonary aspergillus usually requires long-term treatment with glucocorticoids. The major diagnostic criteria are bronchial asthma, pulmonary infiltrates, eosinophilia greater than 1000, immediate wheal and flare response to Aspergillus fumigans, serum precipitins to A. fumigans, elevated serum IgE, and central bronchiectasis.

A 31-year-old African American man presents with dyspnea on exertion. He also has fever and red tender rash on his shins. Physical examination reveals fine inspiratory crackles in both lower lung lobes and tender erythematous nodules on his legs. CXR shows bilateral hilar adenopathy and reticulonodular changes in both lungs. Transbronchial biopsy reveals noncaseating granulomas. Which of the following is the most appropriate next step in management?

Relatively asymptomatic patients often require no treatment. Steroids are used with ocular (as in this case), CNS, or other serious complications. Although 50% of patients are left with permanent organ impairment, these are usually not symptomatic or significant. Only in 15–20% of cases does the disease remain active or recur. Glucocorticoids are the treatment of choice, but numerous other agents have been used.

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A 53-year-old man with a long respiratory history is admitted to the hospital because of increasing shortness of breath and sputum production. He is started on antibiotics and inhaled bronchodilators and anticholinergic agents. The next day he is found in his room confused and sleepy. A PCO2 determination reveals severe hypercarbia (PCO2 70 mmHg). Which of the following explanations regarding his elevated PCO2 is correct?

The administration of oxygen may worsen the syndrome of carbon dioxide narcosis because the chief stimulus to ventilation is often hypoxia, and when this is suddenly relieved, the ventilation may drop quickly. Causes of the chronic hypoventilation syndrome include impaired respiratory drive (e.g., prolonged hypoxia, central nervous system [CNS] disease), neuromuscular disorders (e.g., motor neuron disease, myasthenia gravis), or impaired ventilatory apparatus (e.g., kyphoscoliosis, COPD).

A 63-year-old woman is seen in the emergency room with acute shortness of breath. There is no history of heart or lung problems in the past. She was recently diagnosed with breast cancer and is undergoing active treatment. On examination, her blood pressure is 120/80 mm Hg, pulse 100/min, and heart and lungs are normal. There are no clinical signs of deep venous thrombosis (DVT). Which of the following investigations is most likely to rule out a pulmonary embolism (PE)?

The perfusion lung scan is most valuable in ruling out a PE. If properly performed early in the course of symptoms, a normal scan rules out the diagnosis. High-probability scans are usually considered enough evidence of PE to warrant definitive treatment. Intermediate- or low-probability scans may require further investigation (e.g., with pulmonary angiography), depending on the prior probability of disease. More recent data suggest that a normal high-resolution chest CT with contrast rules out clinically significant PE and is replacing perfusion scanning since the lung images may provide an alternate diagnosis for the patient’s symptoms.

A40-year-old woman has been complaining of a 3-year history of increasing dyspnea and fatigue. She has no other medical illness. Physical examination reveals increased jugular venous pressure (JVP) with prominent c-v wave, and a reduced carotid pulse. Precordial examination reveals a left parasternal lift, loud P2, and rightsided S 3 and S4. There are no audible murmurs. CXR reveals clear lung fields and an ECG shows evidence of right ventricular hypertrophy. Pulmonary function tests show a slight restrictive pattern. Primary pulmonary hypertension is suspected. Which of the following is the most appropriate test to confirm the diagnosis?

Open lung biopsy is not required. Pulmonary angiography is usually performed only if a lung scan suggests thromboembolic disease. Cardiac catheterization is useful to exclude an underlying cardiac shunt as the cause of the pulmonary hypertension. The pulmonary capillary wedge pressure is normal but can be difficult to obtain.

A 63-year-old man is having symptoms of shortness of breath. As part of his workup, an arterial blood gas is done and the PCO2 is 60 mm Hg. Which of the following is the most likely cause for the elevated PCO 2?

Hypoventilation always causes both hypoxemia and hypercapnia. If the hypoventilation syndrome is caused exclusively by impaired respiratory drive (e.g., drug overdose), then the alveolar-arterial PaO2 gradient remains normal. Often, hypoventilation results from more than one disorder in the respiratory system (e.g., COPD plus metabolic alkalosis secondary to diuretics and glucocorticoids).

A 56-year-old man is evaluated for chronic cough. It is present most of the time and is progressively getting worse over the past 3 years. With the cough he usually has white to yellow sputum that he has to expectorate. There is no history of wheezing, asthma, congestive heart failure (CHF), or acid reflux disease. He currently smokes one pack a day for the past 25 years. On examination, his chest is clear. CXR is normal and his forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) on spirometry are normal. Which of the following is the most likely diagnosis?

Chronic bronchitis is a clinical diagnosis defined by the presence of chronic productive cough for 3 months in each of 2 successive years in a patient in whom other causes of chronic cough have been excluded. Emphysema is a pathologic term describing the abnormal permanent enlargement of airspaces distal to the terminal bronchioles, accompanied by destruction of their walls without obvious fibrosis. Emphysema may be noted in patients with COPD.

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A 58-year-old man is recently diagnosed with bowel cancer. He now complains of vague chest discomfort and shortness of breath. On examination, he is unwell, blood pressure 90/50 mm Hg, pulse 110/min, respirations 26/min, and oxygen saturation 88%. His lungs are normal on auscultation, the JVP is 8 cm, and P 2 is loud. There is no edema or leg tenderness on palpation. A quantitative (ELISA) D-dimer assay is positive, ECG reveals sinus tachycardia, and cardiac enzymes are negative. The lung scan is read as high probability for PE. Which of the following tests is most likely to help in guiding emergent therapy?

In most circumstances, treatment is anticoagulation to prevent further pulmonary emboli. However, hemodynamic instability may warrant primary therapy for the embolus (e.g., thrombolysis). Evidence of right ventricular hypokinesis on echocardiogram can be an indication for such primary therapy.

A 40-year-old man has a routine CXR, which reveals a posterior mediastinal mass. Which of the following is the most likely diagnosis?

Neurogenic tumors are the most common posterior mediastinal masses. Other posterior mediastinal masses include meningoceles, meningomyeloceles, gastroenteric cysts, and esophageal diverticula. Common anterior mediastinal masses include thymomas, lymphomas, teratomas, and thyroid masses. Middle mediastinal masses include vascular lesions, lymph nodes, and pleuropericardial and bronchogenic cysts.

A 35-year-old man is evaluated for symptoms of shortness of breath. He reports no other lung or heart disease. He smokes half pack a day for the past 10 years. On examination, his JVP is 2 cm, heart sounds normal, and lungs are clear. A CXR shows hyperinflation and increased lucency of the lung fields. A chest CT reveals bullae and emphysematous changes, while pulmonary function tests show an FEV1/FVC ratio of <70%. Evaluation of his family reveals other affected individuals. Which of the following is the most likely diagnosis?

Most people have two MM genes and a resultant alpha1-antitrypsin level in excess of 2.5 g/L. Homozygotes with ZZ or SS genotypes have severe alpha1-antitrypsin deficiency and develop severe panacinar emphysema in the third or fourth decade of life. Smoking is an important cofactor in the development of disease. Heterozygotes (MZ or MS) have intermediate levels of alpha1-antitrypsin (i.e., genetic expression is that of an autosomal codominant allele). This heterozygous state is common (5–14% of general population), but it is unclear whether it is associated with lung function abnormalities.

A 23-year-old man notices a gradual but progressive increase in breathing difficulty. He has a long history of back pain with prolonged morning stiffness. He has also had an episode of iritis in the past. On examination, there is reduced range of motion in the lumbar spine with forward flexion and pain on palpation of the sacroiliac joint and surrounding soft tissue. X-rays of the pelvis show erosions and sclerosis of the sacroiliac joint. Which of the following is the most likely pulmonary complication of this condition?

Ankylosing spondylitis is characterized by bilateral upper lobe fibrosis, which may be complicated by fibrocavitary disease. The pulmonary involvement is rare and is usually very slowly progressive. The cavities can be colonized by Aspergillus.

A 44-year-old woman has been complaining of a 4-year history of increasing dyspnea and fatigue. Physical examination reveals increased JVP and a reduced carotid pulse. Precordial examination reveals a left parasternal lift, loud P 2, and right-sided S3 and S4. There are no audible murmurs. CXR reveals clear lung fields and an ECG shows evidence of right ventricular hypertrophy. Pulmonary function tests show a slight restrictive pattern. A diagnosis of primary pulmonary hypertension is made. Which of the following is the most likely cause of death in this condition?

The natural history of the disease is unclear because the disease is asymptomatic for a long period. Survival from diagnosis is dependent on the functional class of the patient. Functional class IV dyspnea suggests a mean survival of only 6 months. Death is usually the result of either intractable right heart failure or sudden death.

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A patient with hypoxemia, hypercapnia, and polycythemia is able to restore his blood gases to normal by voluntary hyperventilation. Which of the following is the most likely location for the abnormalities seen on his blood gases?

The primary pathology is likely to be located in the respiratory center. Cyanosis, especially when asleep, is caused by a combination of polycythemia and hypoxia. The symptoms of alveolar hypoventilation are caused by both hypercarbia and hypoxemia.

A 63-year-old woman presents with dyspnea and coughing up foul smelling purulent sputum. She has had many similar episodes in the past. There are no other constitutional symptoms and she denies excessive alcohol intake. On physical examination, she appears chronically ill with clubbing of the fingers. Heart sounds are normal, JVP is measured at 4 cm, and there are inspiratory crackles heard at the lung bases posteriorly. There is no hepatosplenomegaly or any palpable lymph nodes. CXR shows scaring in the left lower lobe, which on chest CT scan is identified as cystic changes with airway dilatation and bronchial wall thickening. Which of the following is the most appropriate initial next step in management?

Antibiotics and postural drainage might be included in therapy. The choice of antimicrobial agents is guided by the sputum culture, but ampicillin and tetracycline are used if normal flora is found. The general principles of therapy include eliminating underlying problems, improved clearance of secretions, control of infections, and reversal of airflow obstruction.

A 32-year-old man develops symptoms of wheezing, cough, and shortness of breath. He has bilateral expiratory wheezes, and the rest of the examination is normal. Further evaluation with pulmonary function tests reveals a reduced FEV1/FVC ratio that corrects with bronchodilators. Which of the following statements about a diagnosis of idiosyncratic asthma (also called nonatopic) is correct?

A significant portion of asthmatics have no known personal or family history of atopy and have normal IgE levels. Idiosyncratic asthma is more likely to have its onset in adult life. Upper respiratory infections can serve as triggers for idiosyncratic asthma.

A 20-year-old African American woman presents with mild dyspnea on exertion and joint discomfort in her knees, wrists, and ankles. She also has a fever and red tender rash on her shins. Physical examination reveals hepatosplenomegaly, generalized lymphadenopathy, corneal opacities, and tender erythematous nodules on her legs. CXR shows bilateral symmetric hilar adenopathy. Transbronchial biopsy reveals noncaseating granulomas. Which of the following is the most likely cause for the eye lesion?

Acute granulomatous uveitis may be the initial manifestation of sarcoidosis. It can cause blindness. About 25% of patients with sarcoid have eye involvement—three-quarters have anterior uveitis and one-quarter have posterior uveitis. Involvement of lacrimal glands can lead to dry, sore eyes.

A 74-year-old man with a history of smoking notices blood in his chronic daily sputum production. He has no fever or chills, but has lost 10 lb in the past 6 months. On examination, he has bilateral expiratory wheezes, and his fingers are clubbed. There are no lymph nodes and the remaining examination is normal. CXR reveals a left hilar mass. Which of the following suggests that the tumor is a small cell lung cancer?

Paraneoplastic syndromes are classified as metabolic, neuromuscular, connective tissue, dermatologic, and vascular. Stevens-Johnson syndrome usually follows drug allergy. Acanthosis nigricans and other cutaneous manifestations (e.g., dermatomyositis) are rare (<1%). Clubbing is common and occurs in up to 30% of non-small cell lung cancers. The various endocrine syndromes occur in 12% of cases. At times, paraneoplastic syndromes may be the presenting finding in lung cancer or be the first sign of recurrence. Most occur with non-small cell lung cancer, but SIADH is more characteristic of small cell lung cancer.

Diseases of the Respiratory System – Part 1
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