LAUSR

TOPIC: Chest Infections TYPE: Medical Student/Resident Case Reports INTRODUCTION: Acute Pulmonary Histoplasmosis (APH) can present in a broad variety of signs and symptoms in immunocompetent individuals but is generally a benign disease that may not require treatment. If symptoms are more severe or longer-lasting, treatment is indicated. CASE PRESENTATION: Two healthy 32- and 36-year-old males (Patient A and B respectively) presented with 1 week of high-grade fever, headache, shortness of breath, productive cough, pleuritic chest pain, and diarrhea. 2 weeks prior, they deep-cleaned a chimney filled with bat guano without wearing their respirators. Upon presentation, both patients had fever, tachycardia, tachypnea with normal resting pulse oximetry despite air hunger. Physical exam revealed diffuse crackle in both lung fields but was otherwise unremarkable. The initial lab only showed elevated procalcitonin and CRP. Viral panels were negative for COVID-19 and other viral infections. Chest CT for both cases showed extensive centrilobular and perilymphatic nodules with associated mediastinal and hilar adenopathy. Based on history and imaging, APH was suspected. Urine Histoplasma antigen was sent which later resulted in positive (3.9 and 7.3 ng/ml respectively). BAL sample was only obtained from patient B due to similarities in the two cases and a possible common pathogen. BAL fluid was grayish in color with 523 nucleated cells and monocytic predominance. Fungitell, aspergillus, fungal culture, and acid-fast stain were all negative. Meanwhile, due to the severity of our patients' presentation and extensive lung involvements, both patients were treated with daily infusion of Amphotericin B for a week and showed significant symptomatic improvement within 2 days. They were switched to oral itraconazole and were eventually discharged from the hospital. Intraconazole was continued for 12 weeks thereafter. DISCUSSION: Histoplasmosis is acquired by inhalation of Histoplasma capsulatum var. capsulatum. Clinical manifestations depend on the intensity of exposure and the patient's immunological status. It has 3 main forms which are acute pulmonary, chronic cavitary pulmonary, and disseminated histoplasmosis. it is generally a self-limited disease. Treatment may be indicated if patient becomes hypoxemic or symptoms persist over 1 month. Guidelines suggest itraconazole as treatment if symptoms persist for more than 1 month and liposomal amphotericin B followed by itraconazole in moderately severe to severe APH. However, in our two cases, patients had moderate symptoms but considering the high intensity of exposure, they were treated with a lower dose of liposomal amphotericin B followed by itraconazole and showed significant improvement. CONCLUSIONS: A detailed history of occupational exposures can help reach a prompt diagnosis and treatment of APH. Patients with moderate symptoms may be considered for treatment with lower doses of amphotericin B followed by itraconazole. REFERENCE #1: 1. Staffolani S, Buonfrate D, Angheben A, et al. Acute histoplasmosis in immunocompetent travelers: a systematic review of literature. BMC Infect Dis. 2018;18(1):673. Published 2018 Dec 18. doi:10.1186/s12879-018-3476-z REFERENCE #2: 2. Sobel JD. Practice guidelines for the treatment of fungal infections. For the Mycoses Study Group. Infectious Diseases Society of America. Clin Infect Dis. 2000 Apr;30(4):652. doi: 10.1086/313746. Epub 2000 Apr 20. PMID: 10770725. REFERENCE #3: 3. L. Joseph Wheat, Alison G. Freifeld, Martin B. Kleiman, John W. Baddley, David S. McKinsey, James E. Loyd, Carol A. Kauffman, Clinical Practice Guidelines for the Management of Patients with Histoplasmosis: 2007 Update by the Infectious Diseases Society of America, Clinical Infectious Diseases, Volume 45, Issue 7, 1 October 2007, Pages 807–825. doi.org/10.1086/521259 DISCLOSURES: no disclosure on file for Ashlee Russo;No relevant relationships by Abolfazl Sodagar, source=Web Response No relevant relationships by Jeannie Ur, source=Web Response