During morning rounds on the hematology-oncology unit, a physician evaluates a patient und… — USMLE Step 2 CK

During morning rounds on the hematology-oncology unit, a physician evaluates a patient undergoing induction chemotherapy for acute myeloid leukemia. The patient, who is $12$ days into his hospital course, reports the sudden onset of chills overnight. His vital signs include a temperature of $39.1^\circ C$ ( $102.4^\circ F$ ), blood pressure of $112/68$ mm Hg, pulse of $105$ /min, and respirations of $18$ /min. Pulse oximetry shows $98\%$ on room air. Detailed physical assessment reveals a clean central venous catheter insertion site with no erythema, tenderness, or exudate. The patient has no oral ulcers, his chest is clear to auscultation, and his skin is fully intact without rashes. Laboratory evaluation is notable for a total leukocyte count of $0.4 \times 10^9$ /L and an absolute neutrophil count of $80$ /mm $^3$ . Blood and urine cultures have been drawn. Which of the following is the most appropriate initial empiric pharmacotherapy for this patient?

A
Intravenous cefepime and intravenous vancomycin
B
Intravenous ceftriaxone
Intravenous cefepimeAnswer
D
Intravenous cefepime and intravenous fluconazole
E
Oral ciprofloxacin and oral amoxicillin-clavulanate

Answer

Intravenous cefepime

This patient has high-risk febrile neutropenia, defined as an absolute neutrophil count

<500

/mm

^3

combined with a single oral temperature

\geq 38.3^\circ C

(

101.0^\circ F

) or sustained

\geq 38.0^\circ C

(

100.4^\circ F

) for

>1

hour. Patients undergoing induction chemotherapy for acute leukemia are inherently high-risk due to the expected prolonged and profound duration of neutropenia. The standard of care for high-risk febrile neutropenia without a clinically apparent source is immediate, empiric intravenous therapy with a broad-spectrum antipseudomonal beta-lactam. Cefepime, meropenem, or piperacillin-tazobactam are all appropriate first-line options.

Step-by-Step Solution

Identify the primary clinical syndrome based on vital signs and laboratory findings.

The patient has a fever (

39.1^\circ C

) and profound neutropenia (ANC of

80

/mm

^3

), meeting the criteria for febrile neutropenia.

Febrile neutropenia is an oncologic emergency requiring immediate empiric antimicrobial therapy.

Risk-stratify the patient to determine the appropriate setting and route of administration.

The patient is undergoing induction chemotherapy for acute myeloid leukemia, which causes prolonged and profound neutropenia, classifying him as high-risk.

High-risk patients require hospitalization (or continuation of inpatient care) and intravenous antibiotics, whereas low-risk patients may sometimes be managed with oral antibiotics.

Select the appropriate antimicrobial spectrum.

An antipseudomonal beta-lactam must be chosen. Because the patient is hemodynamically stable without evidence of pneumonia, skin infection, or catheter-site infection, empiric Gram-positive (MRSA) coverage is unnecessary.

Routine use of vancomycin in all febrile neutropenia cases is contrary to antibiotic stewardship and increases toxicity without improving survival.

Key Concept

Empiric Management of High-Risk Febrile Neutropenia

Estimated Time:1m 15s

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