We undertook a retrospective study to describe the clinical, radiographic, diagnostic, and therapeutic features of pulmonary blastomycosis in an area endemic for this disease.
Mycology data from the University of Kentucky and VA Medical Center were queried for all positive Blastomysosis dermatidis cultures from pulmonary sources from 1992–2003. Medical records were obtained for further analysis of demographic data, clinical findings, treatment, and outcomes. This study was approved by the Institutional Review Board.
The study population consisted of 35 patients with culture proven pulmonary blastomycosis, of which 12 were immunocompromised. The average age at the time of diagnosis was 56 years (range: 23–86 years). All but one patient was symptomatic at the time of presentation. The most common presenting symptoms were: cough (79%), dyspnea (51%), fever (43%), and weight loss (43%). The mean duration of symptoms prior to presentation was 52 days (range: 3–180 days). The most common radiographic abnormalities were air space disease (57%) and single or multiple mass/nodule (28%). The patients had the following diagnostic tests: sputum (66%), serology (63%), bronchoscopy (74%), transthoracic needle aspiration (14%), and open lung biopsy (6%). The yield from these tests was: sputum (48%), serology (27%), bronchoscopy (85%), needle aspiration (66%), and open lung biopsy (100%). Patients were treated with amphotericin B alone (19%), an azole alone (58%), or a combination of these drugs (23%). In this series the mortality rate was 27% and 89% of the deaths occurred in the immunocompromised group.
Pulmonary blastomycosis often presents with subacute or chronic symptoms. Radiographic findings are non-specific, however, the presence of nodules or masses should raise suspicions. Sputum studies and serology are unreliable and more invasive tests such as bronchoscopy are usually required to make the diagnosis. While most patients respond well to therapy, immunocompromised patients have a very high mortality rate.
A high index of suspicion for pulmonary blastomycosis is required in endemic areas, particularly in immunocompromised patients. Invasive testing is usually necessary to make the diagnosis.
D.M. Hiestand, None.