View Abstract

A5398 - Pulmonary Mucormycosis Presenting as a Chronic Infection in a Poorly Controlled Diabetic Diagnosed by Fungal 18s rRNA Sequencing
Author Block: M. B. McCarra; Stanford Division of Pulmonary and Critical Care, Stanford, Stanford, CA, United States.
Introduction: Mucormycosis is an uncommon opportunistic infection that typically affects an immunocompromised host, particularly patients with prolonged neutropenia. Pulmonary mucormycosis is a rare manifestation of the disease and has been most commonly reported in patients with hematologic malignancy, chronic immunosuppression, or following BMT and solid organ transplant patients. Decreased awareness of pulmonary mucormycosis outside this “classic” patient population may lead to delayed diagnosis. This may be compounded by challenges in diagnosis which often requires tissue biopsy as zygomycetes are fragile and difficult to grow in culture. Mortality rates are as high as 76% for mucormycosis associated pulmonary infections and early diagnosis improves outcomes. Case: A 49 year-old male with pertinent past medical history of chronic sinusitis and poorly controlled diabetes mellitus II presented to our hospital with fatigue, weight loss of 30 lbs, and dry cough for three months. The patient was from the California central valley and owned a farming business. He was an everyday smoker. Physical exam was unremarkable and the patient was hemodynamically stable. A chest CT without contrast performed at the time of admission showed a cavitary lesion in the right upper lobe with surrounding ground glass opacities. Labs notable for hemoglobin A1c of 14.7, WBC: 12.4, and CRP of 11. Sputum culture, AFB x3, coccidioidal CF, Asperigillus IgG, HIV, c-ANCA, and p-ANCA were all negative. Given the anatomic location of the lesion navigational bronchoscopy with biopsy was performed. Bacterial and fungal cultures were negative, pathology showed acute inflammation and necrotic debris, however Rhizopus oryzae was identified by 18s fungal sequencing. The patient was started on posaconazole and right upper lobectomy with wedge resection of the right middle lobe was performed. Pathology showed angioinvasive disease consistent with mucormycosis. The patient did well clinically and continues on posaconazole with outpatient infectious disease follow up. Discussion: As highlighted by the present case, while pulmonary mucormycosis is a rare disease heightened degree of clinical suspicion must be maintained even in an atypical population given the high associated mortality. While not specific, particular radiographic findings including reverse halo sign, pleural effusions, and spread of disease across tissue plane are suggestive of mucormycosis. Currently serologic testing specific for mucormycosis does not exist and culture can be difficult. If there is any degree of clinical suspicion mucormycosis should be ruled out by biopsy. Last, 18s rRNA gene sequencing may aid in diagnosis and should be part of the diagnostic workup.