Question 16
A 20-year-old man falls to the ground while jogging along a city street early one morning. He suffers a minor abrasion to his left hand. However, within minutes he is very dyspneic and has right-sided chest pain. He walks into a nearby store, and the manager calls for an ambulance. On arrival at the hospital, he has tachypnea and tachycardia. On physical examination breath sounds are absent over the right lung fields. A chest radiograph shows that the mediastinum is shifted to the left, and there are no fractures. A thoracentesis on the right yields a rush of air. Which of the following conditions is most likely to have given rise to these events?
A Bronchopleural fistula
B Paraseptal emphysema
C Foreign body aspiration
D Intrinsic asthma
E Pulmonary atherosclerosis
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(B) CORRECT. Paraseptal emphysema is not common, but does account for a significant number of cases of spontaneous pneumothorax in young persons. It is not related to smoking. There are subpleural bullae that can burst, even with minimal trauma.
(A) Incorrect. A bronchopleural fistula typically occurs in the setting of a severe lung infection, not in a healthy person.
(C) Incorrect. Aspiration of a foreign body can lead to localized air trapping, but a pneumothorax is not common.
(D) Incorrect. Intrinsic asthma, usually seen in middle aged adults, can be set off by a variety of stimuli, including infections and exposure to cold. Pneumothorax does not typically result.
(E) Incorrect. Both chronic restrictive and obstructive lung diseases can reduce the pulmonary vascular bed to increase pulmonary arterial pressures that promote pulmonary atherosclerosis. The vessels do not rupture.
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Question 17
Following a vehicular accident with blood loss leading to prolonged, severe hypotension, a 30-year-old man is intubated and placed on a mechanical ventilator. He has progressively decreasing oxygen saturations despite increasing PEEP and FI02 of 100%. He remains afebrile. He dies 3 days later. At autopsy, the distal lungs show pink hyaline membranes, thickened interstitium, and many macrophages but few neutrophils. Which of the following pulmonary diseases most likely complicated his course?
A Bronchopneumonia
B Chronic bronchitis
C Bronchiectasis
D Viral pneumonia
E Diffuse alveolar damage
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(E) CORRECT. Diffuse alveolar damage (or ARDS as it is known clinically) is the final event following lung injury from a variety of serious illnesses or accidents. In this case, it was probably initiated by the hypotension ('shock lung') and potentiated by the 100% oxygen.
(A) Incorrect. A bacterial pneumonia, as a nosocomial infection, is likely to be accompanied by signs of sepsis.
(B) Incorrect. Chronic bronchitis develops and continues over months to years, probably from environmental agents.
(C) Incorrect. This is a process that takes at least weeks to months and is due to obstruction of airways in one or more parts of lung.
(D) Incorrect. Viral pneumonias are not likely to be acquired in hospital. They are often complicated by bacterial pneumonia.
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Question 18
A 51-year-old man complains of a slight cough he has had for a week. He is a non-smoker. On auscultation of the chest his lung fields are clear. A chest radiograph shows a subpleural "coin lesion" 2 cm in diameter in the right upper lobe. Which of the following is the most likely diagnosis?
A Small cell anaplastic carcinoma
B Granuloma
C Bronchiectasis
D Exogenous lipid pneumonia
E Silicosis
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(B) CORRECT. The differential diagnosis of a solitary coin lesion most often includes lung cancer (adenocarcinoma most likely), granuloma, or hamartoma.
(A) Incorrect. An 'oat cell' carcinoma tends to spread very quickly and not remain localized. Moreover, it virtually always appears in persons with a history of smoking.
(C) Incorrect. Bronchiectasis with inflammation, destruction, and dilation of bronchi does not produce a round, discrete lesion.
(D) Incorrect. An exogenous lipid pneumonia from aspiration of a substance that is oily or contains much lipid is not typically localized.
(E) Incorrect. Silicosis from inhalation of dust for many years produces diffuse, scattered nodules in the lungs.
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Question 19
A 60-year-old man has had a cough without production of much sputum for the past week. On physical examination he is afebrile. There are decreased breath sounds at the right lung base. A chest x-ray reveals an area of consolidation in the right lower lobe. He is given antibiotic therapy, but a month later the radiographic picture has not changed, and his cough continues. A bronchoalveolar lavage is performed and yields atypical cells along with scattered alveolar macrophages. Which of the following is the most likely diagnosis?
A Mycoplasma pneumonia
B Bronchioloalveolar carcinoma
C Sarcoidosis
D Pulmonary infarction
E Silicosis
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(B) CORRECT. This tumor can spread in a pneumonia-like pattern. The lack of a change over time and the absence of a response to antibiotics should suggest a non-infectious process.
(A) Incorrect. An atypical pneumonia with Mycoplasma is unlikely to be confined to just the right lower lobe, and it would not yield atypical cells.
(C) Incorrect. Sarcoid is likely to produce a granulomatous pattern, and the hilar lymph nodes are usually enlarged as well.
(D) Incorrect. An infarct is unlikely to yield atypical cells.
(E) Incorrect. Silicosis produces interstitial lung disease with silicotic nodules.
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Question 20
A 25-year-old man receives a bone marrow transplant for treatment of acute myelogenous leukemia. He develops increasing dyspnea 3 weeks later, along with fever and cough. On physical examination his temperature is 37.8 C. A chest radiograph shows irregular interstitial infiltrates. A bronchoalveolar lavage is performed an on cytologic examination shows cells that are enlarged and have prominent intranuclear inclusions. He is most likely to have an infection with which of the following organisms?
A Toxoplasma gondii
B Candida albicans
C Cytomegalovirus
D Pneumocystis carinii (jirovecii)
E Mycobacterium tuberculosis
F Influenza B virus
G Respiratory syncytial virus
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(C) CORRECT. CMV produces a cytopathic effect with enlarged cells having prominent intranuclear inclusions.
(A) Incorrect. Toxo is not common in lung. Toxo cysts contain bradyzoites, which are about 2 microns in size. There may be surrounding free tachyzoites of the same size as bradyzoites.
(B) Incorrect. Candida yields budding cells and pseudohyphae.
(D) Incorrect. PCP yields foamy material that appears acellular with H&E and Pap stains.
(E) Incorrect. TB produces a granulomatous reaction. There may be giant cells of the Langhans variety, but a BAL will probably not have much that is diagnostic without an AFB stain or culture.
(F) Incorrect. Influenza virus infections are not characteristic for immunocompromised patients. No characteristic inclusions can be seen in specimens.
(G) Incorrect. Respiratory syncytial virus infections are most common in young children and infants. They are not characteristic for immunocompromised patients. Inclusions are in the cytoplasm with this RNA virus.
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