USMLE Forum Archives - USMLE Step 2 CK - RESPIRATORY
RESPIRATORY
bingousmle - 05-18-10 01:03
A 46-year-old man presents with shortness of breath. Chest x-ray reveals a right pleural effusion extending about halfway up the chest. The patient has no other known medical problems and is on no medicines. The rest of the general physical examination is unremarkable. Diagnostic thoracentesis reveals the following: lactate dehydrogenase 1.7 kat/L (100 U/L), glucose 6.4 mmol/L (150 mg/dL), and amylase 1.6 kat/L (90 U/L). Cell count reveals 1000 red cells per microliter and 1000 white cells per microliter (differential: 50 percent neutrophils, 25 percent lymphocytes, and 25 percent monocytes). A ventilation-perfusion lung scan is indeterminate on the right side because of the large effusion, but there are no ventilation-perfusion mismatches elsewhere. The next most appropriate step would be
A:pulmonary arteriogram
B:abdominal CT
C:chest CT
D:needle biopsy of pleura
E:administration of isoniazid with ethambutol
bingousmle - 05-18-10 01:03
A 46-year-old man presents with shortness of breath. Chest x-ray reveals a right pleural effusion extending about halfway up the chest. The patient has no other known medical problems and is on no medicines. The rest of the general physical examination is unremarkable. Diagnostic thoracentesis reveals the following: lactate dehydrogenase 1.7 kat/L (100 U/L), glucose 6.4 mmol/L (150 mg/dL), and amylase 1.6 kat/L (90 U/L). Cell count reveals 1000 red cells per microliter and 1000 white cells per microliter (differential: 50 percent neutrophils, 25 percent lymphocytes, and 25 percent monocytes). A ventilation-perfusion lung scan is indeterminate on the right side because of the large effusion, but there are no ventilation-perfusion mismatches elsewhere. The next most appropriate step would be
A:pulmonary arteriogram
B:abdominal CT
C:chest CT
D:needle biopsy of pleura
E:administration of isoniazid with ethambutol
The correct answer and explanation will be available after you answer.
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#3
Re: RESPIRATORY mtniharika - 05-18-10 15:23 My answer is: e.
The fluid is also sent for Gram staining and culture, and, if suspicious for tuberculosis, examination for TB markers (adenosine deaminase > 45 IU/L, interferon gamma > 140 pg/mL, or positive polymerase chain reaction (PCR) for tuberculous DNA
#4
Re: RESPIRATORY babbu5508 - 05-19-10 14:04 My answer is: d.
Pleural biopsy is usually done to determine the cause of a collection of fluid around the lung (persistent pleural effusion) or other abnormality of the pleural membrane. Pleural biopsy can diagnose tuberculosis, cancer, and other diseases.
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