Blastomycosis
Blastomycosis Definition
Blastomycosis is a fungal infection caused by the Blastomyces dermatitidis organism. Blastomycosis causes clinical symptoms that have similarites to histoplasmosis. The organism causing blastomycosis is endemic to portions of North America.
Blastomycosis Diagnosis
Once suspected, diagnosis of blastomycosis can usually be confirmed by demonstration of the particular broad based budding organisms in sputum or tissues by KOH prep, cytology, or histology. Tissue biopsy of skin or other organs may be needed in order to diagnose extra-pulmonary disease. Commercially available urine antigen testing seems to be quite sensitive in suggesting the diagnosis in cases where the organism is not readily detected. While culture of the organism remains the definitive diagnostic standard, its slow growing nature can result to delays in treatment of up to several weeks. However, sometimes blood and sputum cultures may not be useful in detecting blastomycosis. A lung biopsy is another option for the diagnosis of blastomycosis, and results will be shown promptly.
Blastomycosis Epidemiology
In the US, blastomycosis is endemic in the Mississippi river and Ohio river basins and around the Great Lakes. The yearly incidence is less than 1 case per 100,000 people in Mississippi, Louisiana, Kentucky, and Arkansas. The cases are higher in northern states such as Wisconsin, where from 1986 to 1995 there were 1.4 cases per 100,000 people. In Canada, most cases of blastomycosis happen in northwestern Ontario, particularly around the Kenora area. The moist, acidic soil in the surrounding woodland harbors the fungus and helps it thrive Blastomycosis can be found internationally; cases are sometimes reported from Africa.
Blastomycosis Symptoms and Signs
Blastomycosis presents a flulike illness with fever, myalgia, chills, and headache. These symptoms are usually accompanied with a nonproductive cough which resolves within days. It also results in an acute illness similar to bacterial pneumonia, with symptoms of high fever, chills, a productive cough, and pleuritic pains in the chest. Patients may also experience a chronic illness that mimics tuberculosis or lung cancer, with signs of low-grade fever, a productive cough, night sweats, and weight loss. There may also be a fast, progressive, and severe disease that manifests as ARDS, with fever, shortness of breath, tachypnea, hypoxemia, and diffuse pulmonary infiltrates. Some patients develop skin lesions, usually asymptomatic, appearing as ulcerated lesions with small pustules at the margins. Patients also complain of bone or joint pain due to bone lytic lesion. Other symptoms include prostatitis which may be asymptomatic and may cause pain on urinating, and involvement of the larynx causing hoarseness.
Drugs used for treatment of Blastomycosis
Nizoral
Sporanox