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Difficulty: Very hardInfectious Diseases

A 62-year-old man is evaluated in the hematology-oncology unit for persistent daily fevers. He was admitted 14 days ago to undergo induction chemotherapy for acute myeloid leukemia. Four days ago, he developed a fever of 38.9°C (102.0°F) when his absolute neutrophil count (ANC) was 200/mm³. After blood cultures were obtained, empiric intravenous cefepime was initiated. Today, his temperature is 38.8°C (101.8°F), blood pressure is 118/76 mmHg, pulse is 98/min, and respiratory rate is 18/min. His current ANC is 100/mm³. The initial blood cultures have shown no growth after 96 hours. The patient now reports the onset of mild, right-sided pleuritic chest pain. Physical examination reveals normal heart sounds and clear lung fields bilaterally. His tunneled central venous catheter site appears clean with no surrounding erythema or induration. A non-contrast chest CT demonstrates a 2.5-cm dense nodule in the right upper lobe surrounded by a distinct rim of ground-glass opacity. Serum galactomannan and beta-D-glucan assays are drawn and pending. Which of the following is the most appropriate next step in management?

  1. Initiate intravenous voriconazoleAnswer
  2. B
    Initiate intravenous caspofungin
  3. C
    Replace cefepime with intravenous meropenem
  4. D
    Add intravenous vancomycin
  5. E
    Withhold further pharmacotherapy until fungal biomarkers return

Answer

The most appropriate next step is to initiate intravenous voriconazole.
This patient's clinical picture is classic for invasive pulmonary aspergillosis (IPA). He has prolonged neutropenic fever unresponsive to broad-spectrum antibacterials, combined with a new onset of pleuritic chest pain and a defining 'halo sign' on his chest CT. The halo sign is caused by a central pulmonary nodule (representing tissue infarction) surrounded by a ring of ground-glass opacity (representing alveolar hemorrhage), which occurs due to the angioinvasive nature of Aspergillus. In profoundly immunocompromised patients, delayed treatment of invasive mold infections is associated with exceedingly high mortality. Therefore, the most appropriate next step is to initiate empiric antifungal therapy with a mold-active triazole, such as voriconazole or isavuconazole, while awaiting definitive diagnostic results like the serum galactomannan assay.

Step-by-Step Solution

1
Analyze the clinical timeline and immune status.
The patient has profound neutropenia (ANC < 500/mm³) and persistent fever for 4 days despite broad-spectrum antipseudomonal beta-lactam therapy (cefepime).
Persistent fever in a neutropenic patient beyond 4-7 days of appropriate antibacterial therapy raises the clinical suspicion for invasive fungal infections.
2
Interpret the new clinical and radiographic findings.
Pleuritic chest pain combined with a CT showing a pulmonary nodule surrounded by ground-glass opacity (the 'halo sign').
The 'halo sign' represents a central area of pulmonary infarction surrounded by alveolar hemorrhage, which is highly characteristic of angioinvasive fungi, primarily Aspergillus species.
3
Determine the standard of care intervention.
Selection of a mold-active triazole (voriconazole or isavuconazole) immediately, rather than waiting for serum galactomannan results.
Invasive pulmonary aspergillosis has a very high mortality rate in neutropenic patients; delaying therapy for definitive diagnostic test results is contraindicated.

Key Concept

Invasive Pulmonary Aspergillosis Management in Neutropenia
Estimated Time:1m 30s
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Topics

Infectious Diseases

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