A 37-year-old man presents to the emergency department for a persistent fever. The patient has felt unwell for the past week and has felt subjectively febrile. The patient has a medical history of a suicide attempt and alcohol abuse. He is not currently taking any medications. The patient admits to using heroin and cocaine and drinking 5-8 alcoholic drinks per day. His temperature is 103°F (39.4°C), blood pressure is 92/59 mmHg, pulse is 110/min, respirations are 20/min, and oxygen saturation is 96% on room air. Cardiopulmonary exam is notable for a systolic murmur heard best along the left sternal border. Dermatologic exam reveals scarring in the antecubital fossa. IV fluids are administered and the blood pressure is subsequently 120/70 mmHg. Which of the following is the most appropriate next step in management for the most likely underlying diagnosis?
Blood cultures
CT scan
Ultrasound
Vancomycin and gentamicin
Blood cultures
This patient is presenting with fever and a systolic murmur suggestive of bacterial endocarditis. The most appropriate initial step in management is to draw blood cultures.

Bacterial endocarditis presents with fever, systemic symptoms (aches, myalgias, and fatigue), and a new murmur typically in a patient with intravenous drug use. These patients introduce bacteria intravenously which then flows to the right side of the heart and can cause right-sided endocarditis. The most appropriate initial step in management is to draw blood cultures. Once blood cultures have been drawn, broad-spectrum antibiotics can be started (vancomycin and gentamicin), and an ultrasound can be performed to further support the diagnosis (or rule out vegetations) and plan operative interventions if necessary.

Wang et al. review the evidence regarding the diagnosis and treatment of infectious endocarditis. They discuss how echocardiogram and blood cultures are the mainstay of diagnosis. They recommend broad spectrum antibiotics.

Incorrect Answers:
Answer B: A chest radiograph may be performed in the workup for bacterial endocarditis; however, it is not the most appropriate initial step in management and is neither sensitive nor specific.

Answer C: A CT scan would not be a very helpful confirmatory test in the diagnosis of bacterial endocarditis. A better confirmatory test would be an ultrasound. It may workup alternative causes of fever such as pneumonia.

Answer D: Ultrasound (echocardiography) would be the imaging test of choice for bacterial endocarditis. It would be performed after blood cultures have been drawn and antibiotics had been started.

Answer E: Vancomycin and gentamicin are the broad-spectrum antibiotics of choice for bacterial endocarditis. They would be started after blood cultures have been drawn and reduce mortality when given early in sepsis.

Bullet Summary:
The most appropriate initial step in the management of bacterial endocarditis after initial stabilization is to draw blood cultures.