275. Delayed Diagnosis of Histoplasmosis in Pediatric Patients due to Atypical Clinical Presentations

BACKGROUND: Histoplasmosis is a systemic mycosis with a wide range of clinical manifestations which represents a diagnostic challenge. It affects immunocompromised patients but also, previously healthy individuals that are exposed to a large inoculum of Histoplasma. The aim of our study was to describe the clinical presentation, epidemiologic features, laboratory/imaging findings and outcome of pediatric patients with histoplasmosis. METHODS: a retrospective study including patients diagnosed as Histoplasmosis according to ICD-10 at a tertiary care center in Mexico City during 2009 to 2019. Clinical, epidemiological and laboratory/imaging data were gathered from each patient’s clinical file. RESULTS: 5 patients with diagnosis of histoplasmosis were included; 2 patients were classified as proven with histopathologic confirmation, 2 patients as probable and 1 patient as possible according to the EORTC/MSG. The mean age of presentation was 7 years, 3/5 patients were male and 3/5 reported exposure to bats. Diagnosis was delayed by an average time of 6 months due to the variability of clinical presentations (progressive disseminated histoplasmosis, spinal histoplasmosis, cerebral histoplasmosis, intestinal histoplasmosis and mild acute pulmonary histoplasmosis). For the diagnosis, 1/5 had positive ELISA, 1/5 positive immunodiffusion (M band), 1/5 positive EIA in cerebrospinal fluid and 2/5 with histopathology findings that matched histoplasmosis. Pulmonary imaging with interstitial infiltrates in 4/5 and evidence of cavitation in one patient. Hemophagocytic syndrome was a complication in 1/5 and medullary syndrome was developed in the patient with spinal histoplasmosis which resolved with treatment. Liposomal amphotericin B was the treatment in 4/5, followed by itraconazole as the maintenance therapy. CONCLUSION: This study shows variable clinical presentations of Histoplasmosis which resulted in an important delay in diagnosis. This study highlights the importance of diagnostic suspicion in both healthy children and immunocompromised patients, always taking into account epidemiological risks such as exposure to bats. DISCLOSURES: All authors: No reported disclosures.