A 65-year-old man is evaluated in the surgical intensive care unit on postoperative day 4 … — USMLE Step 2 CK

A $65$ -year-old man is evaluated in the surgical intensive care unit on postoperative day $4$ following a partial colectomy for recurrent diverticulitis. Over the past $6$ hours, he has developed a fever, chills, and progressively worsening shortness of breath. His medical history is notable for severe chronic obstructive pulmonary disease (COPD) and a known bicuspid aortic valve.

Current vital signs are temperature $39.1^\circ\text{C}$ ( $102.4^\circ\text{F}$ ), blood pressure $82/48\text{ mm Hg}$ , pulse $126/\text{min}$ and regular, and respiratory rate $28/\text{min}$ . Pulse oximetry shows $88\%$ on room air.

Physical examination reveals a diaphoretic man in acute respiratory distress. Jugular venous distention is present. Chest auscultation reveals diffuse bilateral crackles and scattered wheezes. Cardiac auscultation reveals a new, loud, grade $3/6$ decrescendo diastolic murmur heard best at the left sternal border.

His surgical incisions appear clean and intact. A central venous catheter, placed prior to surgery, remains in the right internal jugular vein, and the insertion site is erythematous and tender.

Which of the following is the most appropriate next step in the management of this patient?

Obtain multiple sets of blood cultures and perform bedside echocardiographyAnswer
B
Transport the patient to the radiology suite for computed tomography pulmonary angiography
C
Administer intravenous furosemide and initiate inhaled albuterol therapy
D
Administer intravenous vancomycin and cefepime immediately without delaying for blood cultures
E
Reassure the patient and administer antipyretics, as fever is common on postoperative day 4

Answer

The most appropriate next step is to obtain multiple sets of blood cultures and perform bedside echocardiography.

The patient's presentation of fever, a tender central line site, and a new decrescendo diastolic murmur is highly suspicious for acute infective endocarditis (IE) causing acute aortic regurgitation. The resulting left ventricular volume overload has precipitated cardiogenic shock and pulmonary edema. Because the patient is hemodynamically unstable, the safest and most critical initial diagnostic steps are those performed at the bedside. Blood cultures are mandatory to isolate the causative organism and must be drawn before initiating empiric antibiotics to guide long-term targeted therapy. Bedside transthoracic echocardiography will rapidly confirm the presence of valvular vegetations and assess the severity of regurgitation without risking clinical deterioration during transport.

Step-by-Step Solution

Analyze the clinical presentation.

The patient has a new high fever, hypotension (

82/48\text{ mm Hg}

), hypoxia, an erythematous central line site, and a new diastolic murmur in the setting of a bicuspid aortic valve.

This triad suggests a catheter-related bloodstream infection that has seeded the abnormal aortic valve, causing acute infective endocarditis and acute aortic regurgitation (AR).

Assess the hemodynamic status.

The patient is in mixed cardiogenic and septic shock, making him highly unstable for transport outside of the intensive care unit.

Recognizing instability dictates that all immediate diagnostic and therapeutic interventions must occur at the bedside.

Determine the optimal diagnostic sequence.

Blood cultures must be drawn immediately to identify the pathogen, followed promptly by empiric antibiotics. Bedside echocardiography will evaluate the valve without moving the patient.

In endocarditis, obtaining cultures before antibiotics is a critical stewardship principle to ensure the pathogen can be identified for long-term targeted therapy.

Key Concept

Management of acute infective endocarditis presenting with valvular failure and shock.

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