A 35-year-old woman with chronic granulomatous disease (CGD) develops persistent cough, hemoptysis, and nodular infiltrates on chest X-ray. Sputum culture grows *Aspergillus fumigatus*. She has no evidence of invasive disease. What is the drug of choice for chronic pulmonary aspergillosis in this immunocompromised host?

Explanation

## Diagnosis: Chronic Pulmonary Aspergillosis in an Immunocompromised Host **Key Point:** *Aspergillus fumigatus* is the most common cause of invasive aspergillosis in immunocompromised patients (neutropenia, hematologic malignancy, solid organ transplant, CGD). Chronic pulmonary aspergillosis (CPA) presents with persistent respiratory symptoms, hemoptysis, and radiographic evidence of cavitary or nodular disease. **High-Yield:** Aspergillosis is caused by *Aspergillus fumigatus* (most common), *A. flavus*, and *A. niger*. These are septate hyphae fungi, distinct from the non-septate Mucorales. Treatment choice depends on the clinical form (invasive vs. chronic) and immune status. ## Drug of Choice: Voriconazole | Feature | Voriconazole | Liposomal Amphotericin B | Itraconazole | Caspofungin | | --- | --- | --- | --- | --- | | **First-line for Invasive Aspergillosis** | Yes | Alternative (if azole-intolerant) | No | No (adjunct only) | | **Mechanism** | CYP450 inhibitor, blocks ergosterol synthesis | Binds ergosterol, disrupts membrane | CYP450 inhibitor, blocks ergosterol synthesis | β-1,3-glucan synthase inhibitor | | **CNS Penetration** | Excellent | Poor | Moderate | Poor | | **Lung Penetration** | Excellent | Moderate | Good | Moderate | | **Efficacy in CPA** | Superior | Moderate | Moderate | Not effective | | **Dosing** | 6 mg/kg IV q12h × 2 doses, then 4 mg/kg q12h | 5–10 mg/kg/day IV | 200 mg PO q12h | 50–70 mg/day IV | | **Oral Bioavailability** | Yes (after IV loading) | No | Yes | No | **Clinical Pearl:** Voriconazole is the **gold standard** for invasive aspergillosis and chronic pulmonary aspergillosis. It achieves excellent lung and CNS concentrations, making it superior to amphotericin B for pulmonary disease. In CGD (a phagocytic defect), the patient is at high risk for invasive aspergillosis, and voriconazole provides the best clinical outcomes. **High-Yield:** Liposomal amphotericin B is reserved for: - Voriconazole-intolerant patients - CNS aspergillosis (better CNS penetration than voriconazole in some cases) - Acute invasive disease in severely immunocompromised patients as initial therapy **Mnemonic:** **VORI** for **V**oriconazole = **O**ptimal for **R**espiratory **I**nvasive aspergillosis. ## Why Voriconazole is Superior for CPA 1. **Excellent lung penetration** — achieves high concentrations in respiratory secretions 2. **Fungistatic and fungicidal** — effective against *Aspergillus fumigatus* 3. **Oral bioavailability** — allows transition from IV to oral therapy for chronic management 4. **Proven superiority** — randomized trials show better outcomes vs. amphotericin B 5. **Suitable for CGD** — immunocompromised host requires reliable drug levels