Sunday, January 13, 2008

1 - respiratory system mcqs - 1 to 5

Question 1

A 9-year-old boy was identified in childhood as having an elevated sweat chloride. Though he appeared to be a normal term baby, his neontal course was complicated by the development of meconium ileus. Throughout childhood he has experienced multiple increasingly severe bouts of pneumonia with a productive cough, often with Pseudomonas aeruginosa, and later Burkholderia cepacea, cultured from sputum. Based upon these findings, he is at greatest risk for development of which of the following pulmonary abnormalities?

A Adenocarcinoma

B Bronchiectasis

C Lymphangiectasis

D Pleural fibrous plaques

E Pneumocystis carinii (jiroveci) pneumonia

F Pneumothorax
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(B) CORRECT. The chronic lung disease of cystic fibrosis often includes bronchiectasis, a disease characterized by inflammation with obstruction and dilation and destruction of bronchi. This process is diffuse throughout the lungs. The loss of pulmonary vascular bed with progressive bronchiectasis can lead to pulmonary hypertension and cor pulmonale.

(A) Incorrect. The incidence of lung cancer is not increased with cystic fibrosis.

(C) Incorrect. Dilation of lymphatics is an infrequent occurrence with mediastinal masses such as lymphomas.

(D) Incorrect. Pleural plaques are most frequently seen with pneumoconioses.

(E) Incorrect. Patients with cystic fibrosis usually have lung infections with bacteria such as Pseudomonas.

(F) Incorrect. Pneumonias with cystic fibrosis are unlikely to produce pneumothorax. No bullae form.

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Question 2

A 70-year-old woman has been at an extended care facility for the past two years because of her increasing inability to attend to activities of daily living. She can no longer recognize family members. She has no movement disorder, but is lethargic and spends most of her days in a wheelchair or in bed. She develops an acute febrile illness and is noted to be coughing up increasing quantities of yellowish sputum. Her temperature is 38.2 C. A chest radiograph shows infiltrates that nearly fill the left lower lobe. Her family elects not to treat her acute illness, and she dies 4 days later. At autopsy, there is extensive consolidation of the left lower lobe, with numerous neutrophils within alveoli. Which of the following infectious agents is most likely to cause her pulmonary disease?

A Pneumocystis carinii (jiroveci)

B Listeria monocytogenes

C Cryptococcus neoformans

D Mycobacterium tuberculosis

E Legionella pneumophila

F Staphylococcus aureus

G Streptococcus pneumoniae

H Influenza A virus

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(G) CORRECT. She has a lobar pneumonia, which is most often a community aquired pneumonia (the nursing home counts as a community venue), following a debilitating course of Alzheimer disease. The most common organism is Streptococcus pneumoniae (pneumococcus).

(A) Incorrect. Pneumocystis carinii (jirovecii) pneumonia is most often seen in immunocompromised patients and is typically bilateral and widespread in the lungs.

(B) Incorrect. Listeriosis is infrequent. Some cases occur in immune compromised persons. It can be a congenital infection.

(C) Incorrect. Cryptococcal infections typically occur more frequently in immunocompromised persons.

(D) Incorrect. Tuberculosis produces a granulomatous pattern of infection. In an adult, reinfection or reactivation is the most likely pattern, with upper lobe involvement.

(E) Incorrect. Legionella can produce a florid pneumonia, typically in all lobes, but it is not common.

(F) Incorrect. S. aureus is more likely to be a nosocomial infection and more likely to produce a bronchopneumonia with patchy infiltrates.

(H) Incorrect. Viral pneumonias are common in the elderly but produce interstitial pneumonitis with non-productive cough. However, viral pneumonias are often complicated by bacterial pneumonia.

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Question 3

A 9-year-old girl has complained of difficulty breathing for the past week. Her vital signs include T 37.9 C, P 80/minute, RR 25/minute, and BP 110/60 mm Hg. On physical examination, her lung fields are clear to auscultation. Her heart rate is regular and no murmurs or gallops are heard. A chest radiograph shows prominent hilar lymphadenopathy along with a 1 cm peripheral right lung nodule in the middle lobe. No infiltrates or masses are present. A sputum gram stain shows normal flora and routine bacterial culture reveals no pathogens. Which of the following conditions is she most likely to have?

A Hypersensitivity pneumonitis

B Mycobacterium tuberculosis infection

C Bronchial carcinoid tumor

D Infective endocarditis

E Goodpasture syndrome

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(B) CORRECT. This is a description of the typical 'Ghon complex' of an initial, or primary, TB infection. The peripheral granuloma does not produce symptoms, but the enlarged lymph nodes may impinge upon airways. Most persons with a primary infection, however, are asymptomatic and the infection goes unnoticed.

(A) Incorrect. A hypersensitivity pneumonitis occurs in response to an inhaled antigen and produces small areas of interstitial inflammation throughout the lungs. Lymph nodes are not enlarged.

(C) Incorrect. A carcinoid tumor could produce focal obstruction with a pneumonia, but pulmonary neoplasms in children are rare. Most bronchial carcinoids act in a benign fashion without metastases.

(D) Incorrect. In children, congenital heart disease is the most likely risk factor for infective endocarditis, and most of these lesions will involve the left heart, with systemic embolization. Even if right-sided vegetations embolize, there should be multiple abscesses present.

(E) Incorrect. Goodpasture syndrome is rare at this age, and the pattern is that of diffuse pulmonary hemorrhage with hemoptysis.

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Question 4

On the 11th postoperative day following a radical prostatectomy for adenocarcinoma of the prostate, a 70-year-old man is recovering uneventfully. He then ambulates to the bathroom, but upon returning to his bed he suddenly becomes extremely dyspneic and diaphoretic, with chest pain, palpitations, and a feeling of panic. Which of the following post-operative complications has he most likely developed?

A Pulmonary edema

B Pleural effusion

C Atelectasis

D Thromboembolus

E Diffuse alveolar damage

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(D) CORRECT. The activity of ambulation resulted in sudden movement of a thrombus that formed during his period of immobilization in the leg or pelvic veins. The thrombus became an embolus and traveled to the lungs.

(A) Incorrect. Pulmonary edema does not have this sudden an onset. The edema could result in dyspnea and a cough with frothy sputum. Orthopnea would be a signficant finding with edema.

(B) Incorrect. An effusion would take days to weeks to form. There could be dyspnea.

(C) Incorrect. Post-operative changes should have resolved after a week or so and would have a course of gradual improvement.

(E) Incorrect. DAD occurs following any severe lung injury. It does not have a sudden onset. It does not occur in patients who are up and about.

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Question 5

A 50-year-old woman has lived in Oslo, Norway all her life and worked as a seamstress. She is a non-smoker, but she has had increasing shortness of breath, fever, weight loss, and night sweats for the past 4 months. On physical examination her temperature is 37.6 C. There are fine rales auscultated in all lung fields. A chest radiograph reveals hilar lymphadenopathy and a reticulonodular pattern of small densities in all lung fields. She demonstrates anergy by skin testing to mumps and Candida antigens. A transbronchial biopsy is performed that microscopically shows numerous small pulmonary interstitial non-caseating granulomas. Which of the following is the most likely diagnosis?

A Histoplasmosis

B Adenocarcinoma

C Sarcoidosis

D Usual interstitial pneumonitis

E Berylliosis

F Tuberculosis

G Extrinsic allergic alveolitis

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(C) CORRECT. Sarcoidosis is typified by non-caseating granulomas. However, culture of the tissue and a careful search histologically should be made for organisms.

(A) Incorrect. Histoplasmosis is most common in the Mississippi and Ohio river valleys in the US. The dimorphic fungi tend to mimic tuberculosis and can have granulomas with central caseation.

(B) Incorrect. Adenocarcinoma should yield malignant cells, not granulomas, on biopsy.

(D) Incorrect. UIP is the end result of a diffuse fibrosing alveolitis. Many cases are idiopathic. The end stage is a honeycomb lung. No granulomas are seen.

(E) Incorrect. Though berylliosis can produce sarcoid-like granulomas, it is very uncommon. An environmental history would be helpful.

(F) Incorrect. A miliary pattern of tuberculosis could produce a diffuse reticulonodular pattern, but the granulomas of tuberculosis are typically caseating.

(G) Incorrect. Persistent exposure to allergens may lead to 'farmer's lung' with small granulomas representing type IV hypersensitivity, but there is no good occupational history in this case.

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