Successful Treatment of Pulmonary Blastomycosis with Continuously Infused Amphotericin B Deoxycholate After Failure with Liposomal Amphotericin B

OBJECTIVE: To describe a case of successful treatment of severe pulmonary blasto mycosis with amphotericin B deoxycholate after failure of liposomal amphotericin B. CASE SUMMARY: A 35-year-old male was exposed to damp decomposing wood while cleaning his basement. He subsequently developed a cough, malaise, fever, nausea, vomiting, and diarrhea. He was admitted to the hospital and intubated for worsening pulmonary symptoms. Microscopic examination of his sputum indicated Blastomyces dermatitidis. Liposomal amphotericin B was administered for 6 days, but the patient's temperature reached 39.6 °C and his white blood cell (WBC) count reached 52,300/μL. Extensive consolidation of both lungs fields was observed on chest X-ray. Because of progressive clinical deterioration, the treatment was switched to amphotericin B deoxycholate by continuous infusion. That change resulted in clinical improvement, with abrupt reductions (within 48 hours) in temperature and the WBC count. By day 14 of therapy (day 8 of amphotericin B deoxycholate), the chest X-ray showed improvement in diffuse airspace filling. After 16 days of amphotericin B treatment, intravenous followed by oral voriconazole was administered for 3 months. Eight months later the patient's strength had improved significantly, but he still had occasional episodes of shortness of breath. DISCUSSION: The management of blastomycosis is challenging because of the lack of clinically supporting data. The gold standard for severe pulmonary blastomycosis had been amphotericin B deoxycholate; however, improved safety data with liposomal amphotericin B for other fungal infections has suggested this as an effective alternative. This report describes a patient with severe pulmonary blastomycosis failing 6 days of liposomal amphotericin B, yet he tolerated and clinically responded to continuous infusion of amphotericin B deoxycholate. Based on this case report and a simulated pharmacokinetic/pharmacodynamic analysis, continuous infusion of amphotericin B deoxycholate may be a reasonable option for enhanced efficacy and minimal toxicity in patients with blastomycosis. CONCLUSIONS: Ours is the first case report to use continuous infusion of amphotericin B deoxycholate for the management of pulmonary blastomycosis. These results suggest that liposomal amphotericin B may not be adequate in some patients for the management of B. dermatitidis pulmonary infections.