A 52-year-old man presents to the emergency department for evaluation of a new-onset fever… — USMLE Step 3

A 52-year-old man presents to the emergency department for evaluation of a new-onset fever. He is currently on day 10 of induction chemotherapy with cytarabine and daunorubicin for acute myeloid leukemia. The patient reports feeling fatigued but specifically denies chills, cough, shortness of breath, abdominal pain, or dysuria. He is tolerating a normal diet and oral fluids. He lives in a ground-floor apartment with his wife, who is his primary caregiver, and they have reliable transportation located 15 minutes away from the hospital.

Temperature is 38.6°C (101.5°F), blood pressure is 124/78 mm Hg, pulse is 88/min, and respirations are 14/min. Pulse oximetry is 99% on room air.

Physical examination reveals a well-appearing man in no acute distress. Cardiopulmonary examination is unremarkable. There is a totally implantable venous access device in the right upper chest with no overlying erythema, induration, or tenderness. Skin examination shows no rashes or lesions.

Laboratory studies show:
Hemoglobin: 8.4 g/dL
Platelet count: 42,000/mm³
Leukocyte count: 300/mm³
Neutrophils: 5%
Bands: 0%
Lymphocytes: 85%
Monocytes: 10%
Serum creatinine: 0.9 mg/dL
Total bilirubin: 0.8 mg/dL
Alanine aminotransferase (ALT): 22 U/L

Based on the patient's clinical presentation and risk profile, which of the following is the most appropriate disposition and initial management?

A
Discharge to the patient's home with an oral regimen of ciprofloxacin and amoxicillin-clavulanate
B
Discharge to the patient's home and coordinate daily intravenous cefepime at an outpatient infusion center
Admit the patient to a standard inpatient medical unit for empirical intravenous cefepimeAnswer
D
Admit the patient to an intermediate care unit for continuous telemetry and intravenous cefepime
E
Admit the patient to the intensive care unit for empirical intravenous cefepime and vancomycin

Answer

Admit the patient to a standard inpatient medical unit for empirical intravenous cefepime

This patient presents with febrile neutropenia, defined as a single oral temperature

\geq 38.3^\circ\text{C}

(

101.0^\circ\text{F}

) and an absolute neutrophil count (ANC)

< 500/\text{mm}^3

. His ANC is critically low at

15/\text{mm}^3

, calculated as

\text{Total Leukocytes} \times (\% \text{Neutrophils} + \% \text{Bands})

, or

300 \times 0.05

. Risk stratification is the critical step in determining the disposition setting for febrile neutropenia. While scoring systems like the Multinational Association for Supportive Care in Cancer (MASCC) risk index can identify low-risk patients (score

\geq 21

) who may be candidates for outpatient management, clinical context is paramount. This patient is undergoing induction chemotherapy for acute myeloid leukemia. This treatment invariably causes prolonged (

>7

days) and profound (

\text{ANC} \leq 100/\text{mm}^3

) neutropenia. According to clinical guidelines, expected prolonged and profound neutropenia automatically classifies the patient as high-risk for severe complications, superseding a reassuring MASCC score or a well-appearing clinical status. High-risk patients must be admitted to a standard inpatient medical unit for empirical intravenous broad-spectrum antibiotics. Monotherapy with an antipseudomonal beta-lactam, such as cefepime, meropenem, or piperacillin-tazobactam, is the standard of care.

Step-by-Step Solution

Calculate the Absolute Neutrophil Count (ANC) to confirm and classify the severity of neutropenia.

The ANC is critically low at 15/mm³, which meets criteria for profound neutropenia (<100/mm³).

ANC determines the severity of immunosuppression and guides the urgency of management.

Evaluate the patient's clinical stability and calculate objective risk scores (e.g., MASCC Risk Index).

The patient is hemodynamically stable, appears well, and has a MASCC score of 26, which formally indicates a 'low risk' for complications.

Risk stratification generally helps differentiate patients who can be safely discharged from those who require inpatient care.

Apply the mandatory clinical exceptions to objective scoring systems based on the underlying etiology of neutropenia.

The patient is undergoing induction chemotherapy for acute myeloid leukemia, meaning his neutropenia will be prolonged (>7 days) and profound. This automatically overrides the MASCC score, reclassifying him as high-risk.

Objective scoring systems are inadequate for patients with specific expected disease trajectories, such as hematologic malignancies undergoing induction.

Determine the appropriate disposition setting and empirical therapy based on the high-risk classification.

The patient requires admission to a standard inpatient medical unit for intravenous antipseudomonal beta-lactam monotherapy (e.g., cefepime).

High-risk febrile neutropenia cannot be managed outpatient, and because he is stable without indications for MRSA coverage, intermediate or intensive care units are unnecessary.

Key Concept

Patients undergoing induction chemotherapy for acute leukemia who develop febrile neutropenia are automatically classified as high-risk due to expected prolonged and profound neutropenia, necessitating inpatient admission for empirical intravenous antibiotics regardless of reassuring objective risk scores.

Estimated Time:2m 0s

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