1718. The Natural History of Chronic Pulmonary Coccidioidomycosis in the Pre-Antifungal Era

BACKGROUND: Prior studies to characterize pulmonary coccidioidomycosis (CM) have been limited by small samples. The historical VA-Armed forces CM patient group provides a unique cohort of patients not treated with conventional antifungals to better characterize and describe chronic pulmonary CM with an emphasis on chronic nodules and cavities. METHODS: A retrospective study of 374 VA-Armed forces non-disseminated CM patients diagnosed between 1955 and 1958 and followed to 1966. Patients had a pulmonary nodule or a pulmonary cavity secondary to CM. Basic demographic information, complement fixation serology, and details regarding the nodules and cavities were investigated. RESULTS: The studied population had a median age of 34 with 97% men and 84% white. Eighty percent had no underlying pulmonary disease and concurrent tuberculosis was the most common comorbid pulmonary condition (11%). Patients with cavities had a median complement fixation (CF) serology of 1:2 (interquartile range (IQR) negative 1:8). Patients with nodules had a median CF serology of negative (IQR negative 1:2). The median number of pulmonary nodules was 1 with a median size of 1–1.9 cm. Sixty-nine percent of the nodules had a sharp, well-defined border, while 10% had a calcified border. The median number of cavities was 1 with a median size of 3–3.9 cm. Forty-five percent of the cavity walls were thin, 31% were thick, and 19% were variable in size. Twenty-six percent of the cavities developed during acute infection with 46% developing without a prior history of primary infection. Twenty-nine percent of the cavities were stable in size, 20% increased in size, 5% disappeared, 4% ruptured, and 2% decreased in size. CONCLUSION: This study helps further characterize chronic pulmonary nodules and cavities caused by CM. To the best of our knowledge, this is the largest study of the natural history of chronic CM pulmonary cavities and nodules providing valuable descriptive features. DISCLOSURES: All authors: No reported disclosures.