USMLE Step 3 - Question 26

A 52 year old male with no significant past medical history presents with increasing dyspnea on exertion, fevers, and sharp chest pains. His temperature is 37.8 C, blood pressure 100/60, heart rate 90, respirations 20, and oxygen saturation 95% on room air. Physical examination reveals normal breath sounds and distant heart sounds without a murmur. Chest x-ray shows an enlarged cardiac silhouette, ECG shows normal sinus rhythm with low voltage, and an echocardiogram reveals a large pericardial effusion. Serum protein level was 6 mg/dL and LDH was 150 mg/dL. Pericardiocentesis is done and the results are below:

WBCs normal
RBCs normal

LDH 300 mg/dL

Total protein 6 mg/dL

Adenosine deaminase elevated

Which of the following is the most likely diagnosis?

A. Malignant pericardial effusion

B. Pericardial effusion due to congestive heart failure

C. Tuberculous pericardial effusion

D. Dressler's syndrome

Remember that tuberculosis can occur isolated in the pericardium causing pericarditis and pericardial effusion without other manifestations of TB (i.e. no pulmonary symptoms). In fact, tuberculous pericarditis used to be the most common cause in the United States. The key is an exudate effusion (although the reliability of applying Light's criteria as is used for pleural effusions to a pericardial effusion is controversial) with elevated adenosine deaminase. Look for fevers and night sweats as well.