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Question 34#

A 40-year-old male patient presents to the emergency room with a 1-week history of fever, rigors, and generalized weakness. The patient denies recent travel or sick contacts but admits to intravenous drug use. On examination, he has splinter and subconjunctival hemorrhages. Cardiac examination shows a holosystolic murmur over the left lower sternal boarder. There are no other localizing signs. Chest x-ray and urinalysis are negative. After obtaining blood cultures, the patient is started on intravenous antibiotics and admitted to the medical floor. Twenty-four hours later, all sets of blood culture grow gram-positive cocci in clusters. A transthoracic echocardiogram is negative for vegetations. Which of the following is the best course of action? 

A) Place a peripherally inserted central catheter (PICC) and start vancomycin
B) Repeat blood cultures to confirm the positive cultures were not contaminants
C) Order a transesophageal echocardiogram
D) Continue vancomycin till the patient becomes afebrile, then discharge him on PO linezolid to finish a total of 2 weeks
E) Order a three-phase bone scan

Correct Answer is C

Comment:

The patient is an intravenous drug user who presents with fever, gram-positive bacteremia, a murmur, and evidence of systemic embolization—a picture consistent with infective endocarditis (IE). The positive blood cultures in this case are highly unlikely to represent contaminants. Ordering transesophageal echocardiogram (TEE) despite the negative transthoracic echocardiogram (TTE) is appropriate, given the former test’s higher sensitivity. Repeating blood cultures 3 to 4 days after initial positive cultures and as needed thereafter is recommended to document clearance of bacteremia. In the case of gram-positive bacteremia, the duration of treatment is counted from the first negative blood culture. Placing long-term intravenous catheters like peripherally inserted central catheter (PICC) should be delayed, if possible, until the gram-positive bacteremia clears. It is not appropriate to treat IE with oral or bacteriostatic antibiotics. Once IE is confirmed, the patient at hand will require 6 weeks of IV antibiotics. There is nothing in the patient’s presentation that is suggestive of osteomyelitis to require a bone scan.