TO CAVITATE OR NOT TO CAVITATE: ATYPICAL PRESENTATION OF A COMMON PATHOGEN

Abstract

SESSION TITLE: Medical Student/Resident Chest Infections Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: A patient with extensive cavitary lung disease and new diagnosis of Human Immunodeficiency Virus (HIV) infection who described clinical features suggestive of pneumocystis jiroveci (PCP) infection failed to improve with initial management. She was subsequently diagnosed with histoplasmosis after bronchoalveolar lavage (BAL) and transbronchial biopsy with a successful treatment response. CASE PRESENTATION: A 40 year-old woman with a past medical history of asthma and tobacco abuse presented with a two-week history of productive cough and pleuritic chest pain. She also reported a 40 pound unintentional weight loss over the past several months and denied hemoptysis. The patient was newly diagnosed with HIV (CD4 count of 41). Chest radiography showed extensive cavitary disease in the right upper lung lobe (RUL) and increased interstitial markings. Computed tomography showed multiple areas of peripheral soft tissue attenuation with central cavitation, the largest in the RUL measured at 7.4 cm, but no mediastinal or hilar lymphadenopathy. Her T-spot mycobacterium tuberculosis (TB) test was negative as were two expectorated sputum samples tested for TB by polymerase chain reaction. The patient underwent bronchoscopy with BAL. PCP smear from bronchial washings was positive, but the patient failed to improve after initial treatment with trimethoprim-sulfamethoxazole and steroids. Transbronchial lung biopsy (TBLB) of the right upper lobe showed lung parenchyma with fungal organisms in a background of necrosis and acute and chronic inflammation. The Grocott Methenamine Silver (GMS) stain of TBLB showed numerous budding yeast suggestive of Histoplasmosis. Fungal culture from BAL eventually grew Histoplasma capsulatum. The patient was treated with a two-week course of amphotericin B and transitioned to daily oral itraconazole for 12 months. DISCUSSION: Cavitary lesions in an immunocompromised patient should always prompt a search for an infectious cause. Although certain pathogens such as Staphylococcus aureus may cause cavitation during acute illness, cavitation due to infection is usually associated with chronic illnesses. Chronic infections most commonly associated with pulmonary cavitations are TB, Histoplasma, Aspergillus, Blastomyces, and Cryptococcus, among others. Cavitary lesions are a rare manifestation of PCP, and a solitary cavity is more common than multiple cavities. Fungal infections can be difficult to diagnose, given the poor sensitivity of culture, cross-reactivity of antigens and antibodies, and the modest sensitivity in BAL. As illustrated in our case, multiple tests may be needed to confirm the diagnosis. CONCLUSIONS: The presence of a cavitary lesion should lower the threshold for performing transbronchial biopsy in addition to BAL. Furthermore, this case calls to consider the interaction between different infectious processes as a contributing factor of such atypical presentation. Reference #1: Wheat J. Endemic mycoses in AIDS: a clinical review. Clin Microbiol Rev. 1995;8(1):146-59. Reference #2: Holt MR, Chan ED. Chronic Cavitary Infections Other than Tuberculosis: Clinical Aspects. J Thorac Imaging. 2018;33(5):322-333. Reference #3: Gallant JE, Ko AH. Cavitary pulmonary lesions in patients infected with human immunodeficiency virus. Clin Infect Dis. 1996;22(4):671-82. DISCLOSURES: No relevant relationships by JENNIFER CHIURCO, source=Web Response No relevant relationships by Jaime Palomino, source=Web Response No relevant relationships by Osman Perez, source=Web Response No relevant relationships by Hanyuan Shi, source=Web Response