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Difficulty: MediumInfectious Diseases

A 54-year-old woman is evaluated in the oncology clinic for a new-onset fever. She is currently receiving induction chemotherapy for acute myeloid leukemia. Yesterday, her temperature was normal, but today she reports a sudden onset of chills and a temperature of 38.8°C (101.8°F). She has no cough, dyspnea, dysuria, abdominal pain, or diarrhea. Vital signs show a blood pressure of 115/75 mm Hg, a pulse of 105/min, and respirations of 16/min. Physical examination reveals a right internal jugular central venous catheter with no surrounding erythema, induration, or purulent drainage. Cardiopulmonary, abdominal, and skin examinations are otherwise unremarkable. Laboratory studies show:

Hemoglobin: 9.2 g/dL
Platelets: 45,000/mm³
Leukocytes: 800/mm³
Neutrophils: 10%
Lymphocytes: 80%
Monocytes: 10%

Blood and urine cultures are obtained. Which of the following is the most appropriate next step in management?

  1. Intravenous cefepimeAnswer
  2. B
    Intravenous vancomycin and intravenous cefepime
  3. C
    Oral ciprofloxacin and oral amoxicillin-clavulanate
  4. D
    Intravenous fluconazole
  5. E
    Observation pending culture results

Answer

Intravenous cefepime
This patient is presenting with febrile neutropenia, an oncologic emergency defined by a single oral temperature of ≥ 38.3°C (101°F) and an absolute neutrophil count (ANC) of < 500/mm³. In this case, the calculated ANC is 80/mm³ (800 leukocytes/mm³ × 10% neutrophils). High-risk patients, such as those with profound neutropenia (ANC < 100/mm³) or those undergoing induction chemotherapy for acute leukemia, require immediate hospitalization and empiric intravenous antibiotics. The initial regimen must provide broad-spectrum coverage against both Gram-positive and Gram-negative organisms, with specific and robust activity against Pseudomonas aeruginosa. Monotherapy with an antipseudomonal beta-lactam, such as intravenous cefepime, meropenem, or piperacillin-tazobactam, is the guideline-concordant appropriate next step.

Step-by-Step Solution

1
Calculate the Absolute Neutrophil Count (ANC).
ANC = Total Leukocytes × (% Neutrophils + % Bands). ANC = 800 × 0.10 = 80/mm³.
To determine if the patient meets the criteria for neutropenia (ANC < 500/mm³ or expected to drop below 500/mm³ within 48 hours).
2
Identify the clinical syndrome.
The patient has a fever of 38.8°C and an ANC of 80/mm³, confirming the diagnosis of febrile neutropenia.
Febrile neutropenia is an oncologic infectious emergency requiring immediate empiric therapy.
3
Stratify the patient's risk level.
The patient is classified as high-risk due to profound neutropenia (ANC < 100/mm³) and undergoing induction chemotherapy for a hematologic malignancy.
Risk stratification determines whether the patient can be treated with oral antibiotics as an outpatient or requires inpatient intravenous therapy.
4
Select the appropriate empiric antimicrobial regimen.
Inpatient therapy with an intravenous antipseudomonal beta-lactam (such as cefepime) is selected.
High-risk febrile neutropenia requires immediate broad-spectrum coverage, particularly against Pseudomonas aeruginosa. Without specific indications like a catheter infection or hemodynamic instability, adding MRSA coverage (vancomycin) is not recommended.

Key Concept

High-risk patients with febrile neutropenia require immediate empiric treatment with an intravenous antipseudomonal beta-lactam (e.g., cefepime, meropenem, or piperacillin-tazobactam). Empiric addition of MRSA coverage is not routinely indicated unless specific risk factors are present.
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Infectious Diseases

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