Study objectives: To study the epidemiologic and clinical features of blastomycosis in northeast Tennessee.
Design: Retrospective review of blastomycosis cases in the region from 1980 through 1995.
Setting: Hospitals located in the Tri-Cities region of northeast Tennessee.
Patients: Seventy-two patients with confirmed blastomycosis infection.
Results: During the 1980 to 1995 study period, we documented 72 cases of blastomycosis. The mean age was 52 years (range, 13 to 86 years), most were male (69.4%), and nine were immunocompromised. A possible environmental exposure was noted for 28 patients. Pulmonary involvement represented the most common site of infection (61 cases), but multiorgan involvement was common (17 cases). Most patients with pulmonary blastomycosis (66%) presented with a chronic illness, and radiologic findings usually revealed local consolidation or a mass-like lesion. Nine patients developed ARDS with an associated mortality rate of 89%, compared with a 10% mortality for non-ARDS pulmonary cases. Antifungal treatment regimens varied widely, with amphotericin B often used for sicker patients. An epidemiologic evaluation revealed that the mean yearly incidence rate for blastomycosis quadrupled between 1980 and 1987 (0.31 cases/100,000 population) and 1988 to 1995 (1.23 cases/100,000 population) (p=0.00001). Most new blastomycosis cases in the 1988 to 1995 period occurred in three counties in the region where significant new construction projects have been underway.
Conclusion: Blastomycosis is endemic in northeast Tennessee and the number of cases is increasing, coinciding with major new construction in the region. Clinicians in the area must be alert to this condition.