A preschool-aged male is evaluated in the emergency department due to a new-onset fever of… — USMLE Step 2 CK

A preschool-aged male is evaluated in the emergency department due to a new-onset fever of $39.4^\circ\text{C}$ ( $102.9^\circ\text{F}$ ) and extreme lethargy. The patient is currently in the consolidation phase of cytotoxic chemotherapy for an underlying high-risk neuroblastoma. Two days prior to arrival, an implanted central venous access port was surgically placed without immediate complications. On evaluation, he is tachycardic at $165/\text{min}$ , tachypneic at $32/\text{min}$ , and hypotensive with a blood pressure of $72/40\text{ mm Hg}$ . Capillary refill time is $4\text{ seconds}$ . The surgical site appears clean with no surrounding erythema, and the lungs are clear to auscultation. A complete blood count reveals a total leukocyte count of $400/\text{mm}^3$ with $10\%$ segmented neutrophils and $5\%$ band forms. What is the most appropriate next step in the management of this patient?

A
Transport the patient to the radiology suite for a computed tomography scan of the abdomen to locate the infectious source
B
Administer antipyretics and continue close observation, as the fever is an expected physiological response on postoperative day two
C
Administer the overdue live-attenuated measles, mumps, and rubella vaccine prior to hospital admission to prevent concurrent viral infections
D
Prescribe oral amoxicillin and arrange outpatient follow-up, as the absolute neutrophil count is evaluated to be safely above the threshold for severe neutropenia
Obtain blood cultures, administer rapid intravenous fluid boluses, and immediately initiate broad-spectrum antipseudomonal antibioticsAnswer

Answer

Obtain blood cultures, administer rapid intravenous fluid boluses, and immediately initiate broad-spectrum antipseudomonal antibiotics.

The correct course of action addresses two simultaneous life-threatening conditions: febrile neutropenia and impending septic shock. This patient has an absolute neutrophil count (ANC) of

60/\text{mm}^3

(calculated as

400 \times [0.10 + 0.05]

), which is firmly in the category of severe neutropenia (ANC

< 500/\text{mm}^3

). Combined with fever and clear signs of hemodynamic instability—including hypotension, prolonged capillary refill, and tachycardia—this clinical picture indicates an oncologic emergency. The absolute highest priority is rapid physiological stabilization. This involves administering intravenous fluid boluses to restore intravascular volume and immediately initiating empiric broad-spectrum antipseudomonal antibiotics (e.g., cefepime or piperacillin-tazobactam) after promptly drawing blood cultures. Any delay in delivering these interventions increases mortality.

Step-by-Step Solution

Calculate the absolute neutrophil count (ANC) using the provided laboratory values.

\text{ANC} = \text{Total WBC} \times (\%\text{ neutrophils} + \%\text{ bands})

. Thus,

\text{ANC} = 400 \times (0.10 + 0.05) = 60/\text{mm}^3

Accurately determining the ANC is crucial to identifying severe neutropenia (ANC

< 500/\text{mm}^3

) in oncology patients.

Evaluate the patient's vital signs and peripheral perfusion to assess hemodynamic stability.

The patient demonstrates tachycardia (

165/\text{min}

), hypotension (

72/40\text{ mm Hg}

), and prolonged capillary refill (

4\text{ seconds}

These findings are classic indicators of decompensated septic shock, which requires immediate, aggressive intervention.

Determine the priority of clinical interventions based on the diagnosis of febrile neutropenia with septic shock.

The immediate priority is resuscitation with intravenous fluid boluses and the administration of broad-spectrum antipseudomonal antibiotics following blood cultures.

In unstable patients, life-saving physiological stabilization and empiric treatment must precede any attempts at detailed diagnostic imaging or source localization.

Key Concept

Management of febrile neutropenia and impending septic shock in pediatric oncology patients.

Estimated Time:1m 30s

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