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Clinically, blastomycosis can be difficult to recognize even in the endemic areas where clinicians are aware of this problem. In only 18% of 123 patients from the University of Mississippi Medical Center (Jackson, MS) blastomycosis was correctly suspected at the initial patient evaluation. Pneumonia sensu latu (40%), malignant tumors (16%), and tuberculosis (14%) were the most common misdiagnoses. The false first impression frequently resulted in unnecessary surgeries or treatment delays, with patients receiving inefficient antibiotic therapy for months. The presence of cutaneous involvement by the disease makes its' recognition easier for the clinician, raising the percentage of correct initial diagnosis to 64%. To evaluate the association with immunodepression, the presence of other diseases was also searched among the 123 patients. An immunodepressive condition preceded the fungal disease in 25% of patients. Another associated disease commonly found in blastomycotic patients was diabetes mellitus (22%). Blastomycosis is correctly suspected at the first clinical evaluation in only a small percentage of patients; pneumonia, cancer, and tuberculosis are the most common clinical considerations. Cutaneous involvement leads the clinician to the correct diagnosis in the majority of cases. One fourth of the patients with blastomycosis had underlying immunodepressive conditions, and underlying diabetes mellitus is present in 22% of patients., (Copyright 2002, Elsevier Science (USA). All rights reserved.)

Blastomycosis can only be diagnosed through the identification of the yeasts of Blastomyces dermatitidis in body fluids, tissues, or cultured material. The charts from 123 patients treated for blastomycosis at the University of Mississippi Medical Center from January 1980 through May 2000 were reviewed to determine the role of wet preparation, cytology, histology, and culture in diagnosing this fungal disease. Cytology uncovered the etiologic agent in 56.1% of all cases and in 71.8% of pulmonary cases. Cytology also was the first method to disclose the fungus in 57.7% of pulmonary cases. Sputum was the cytology specimen examined in 51% of the patients. In 69 patients with lung involvement, pulmonary cytology was positive in 97% of cases. Wet preparation was the second method to most commonly uncover the fungus in 37.4% of all cases. Histology was the third method with 32.5% of positive cases. Cultures were positive in 64.2% of all cases but they were the first to detect the fungus in only 3.2% of all patients. There was pulmonary involvement in 87% of patients, cutaneous involvement in 20%, osseous involvement in 15%, and central nervous involvement in 3%. In the medical literature the relative proportion of pulmonary versus disseminated disease clearly increased in series reported after 1959. Proportionally to the pattern of patients admitted to the University of Mississippi Medical Center, there is a clear predominance of black males among patients with blastomycosis followed by black females. White females constitute the sex/ethnic group least affected by this fungal disease.

In order to clarify the epidemiology and clinical spectrum of endemic blastomycosis, we reviewed the charts of 326 culture and/or histologically proven cases of blastomycosis in Mississippi from 1979 to 1988. Cases were dispersed throughout the state, but counties in central and south-central Mississippi reported 63% of all blastomycosis cases. The average annual incidence rate was 1.3 cases per 100,000 population. The majority of cases were in men (male to female ratio 1.7:1), and most patients were aged in their third through seventh decades (82%). Outdoor occupations were noted for only 28.9% of cases. Cases occurred throughout the year with no significant seasonal peak. Although 55% saw a physician within 7 days of onset of illness, 29% presented after 1 month. Despite early presentation, diagnosis was often delayed for more than 1 month (43.3%). Single organs were involved in 82.8% of cases. For all cases, organ systems involved included lungs (91.4%), skin (18.1%), bone (4.3%), genitourinary system (1.8%), and central nervous system (1.2%). The presence of skin or bone disease was associated with multiorgan involvement. Thirty-three patients died (11.5%), 6 of whom received no therapy. Patients who died were significantly older than those who survived. A successful outcome without relapse was noted in 86.5% of amphotericin B-treated patients and in 81.7% of ketoconazole-treated patients. The relapse rate for ketoconazole-treated patients was higher than for amphotericin B-treated patients (14% and 3.9% respectively).