Source: Carver PL. Invasive
Fungal Infections. In: DiPiro, JT, Talbert RL, Yee GC, Matzke GR,
Wells BG, Posey LM. Pharmacotherapy: A Pathophysiologic Approach.
8th ed. http://accesspharmacy.com/content.aspx?aid=8005562.
Accessed June 24, 2012.
- Systemic fungal infection
- Systemic fungal infection caused by Blastomyces
- Pulmonary infection probably occurs by inhalation of conidia,
which convert to yeast form in lung.
- Inflammatory response, followed by cell-mediated immunity
and formation of noncaseating granulomas
- B. dermatitidis considered
to be soil inhabitant, though attempts to isolate it in nature have
frequently been unsuccessful.
- Has been found in soil containing decayed vegetation, decomposed
wood, and pigeon manure.
- Found in south central and midwestern United States and Canada.
- No sex, age, or occupational predilection
- Review of sporadic cases suggests that people with outdoor
occupations that expose them to soil at highest risk.
- Can disseminate to virtually every other body organ, including
skin, bones, and joints, or the genitourinary tract, without evidence
of pulmonary disease.
- Colonization does not occur.
- Acute pulmonary blastomycosis
- Generally asymptomatic
or self-limited disease
- Characterized by fever, shaking chills, and productive, purulent
cough, with or without hemoptysis in immunocompetent individuals
- Difficult to differentiate from other respiratory infections
based on symptoms
- Sporadic pulmonary blastomycosis
- More chronic
or subacute disease
- Characterized by low-grade fever, night sweats, weight loss,
and productive cough resembling that of TB rather than bacterial
- Chronic pulmonary blastomycosis
by fever, malaise, weight loss, night sweats, chest pain, and productive
- Evidence of disseminated disease can appear 1–3 years
after resolution of primary pneumonia.
- 40% of
patients with disseminated disease do not have reactivation of pulmonary
- Most common sites include skin and bony skeleton.
- Male urogenital tract may also be involved.
Means of Confirmation
- Direct microscopic visualization of large, multinucleated
yeast with single, broad-based buds in sputum or other respiratory
specimens, following digestion of cells and debris with 10% potassium
- No reliable skin test available
- Culture secretions: Up to 30 days required to isolate
and identify small inoculum.
- Complete blood count (CBC): Leukocytosis and anemia may be
- Histopathologic examination of tissue biopsies and culture
- Bacterial pneumonia
- Other fungal infection
- Resolution of clinical abnormalities
- Prevention of relapse
- Eradication of infection
- Mild pulmonary blastomycosis
- Use of antifungal
therapy based on:
- Clinical presentation and immunocompetency
- Toxicity of antifungal agents
- All immunocompromised patients and patients with progressive
or extrapulmonary disease should be treated (Table 1).
uncommon opportunistic disease in immunocompromised patients, including those
- Late and frequently fatal complication