Blastomycosis natural history, complications and prognosis

Blastomycosis is a granulomatous disease entity, that can produce a wide array of signs and symptoms, but is usually a mild illness in many cases. The most common presentation is a mild acute pneumonia that is self-resolving, it can also cause chronic pneumonia and extra-pulmonary manifestations. The most common site of involvement is lungs, but it can often spread to other sites such as skin, bones and genitourinary systems. The route of spread is most commonly either hematogenous or lymphatic.

• Symptoms of acute blastomycosis include an influenza like illness with fever, cough, myalgia, arthralgia, and pleurisy developing 3-15 weeks after exposure.^[1]
• In most of the individuals the infection resolves spontaneously even without the treatment.
• But in some individuals with out treatment it may progress to a more chronic stage which confounds the diagnosis, mistaking it for tuberculosis, other fungal infections or even a malignancy.
• Patient may develop symptoms of high grade fever, productive cough, hemoptysis and weight loss.
• A significant proportion of these cases may further disseminate to other body parts, most commonly to skin, followed by bone and joint, genitourinary system and other sites in the body (nervous system and lymphatics).
• Leading to septicemia and finally death.

Complications that can develop as a result of Blastomycosis include :

• Pulmonary fibrosis
• Cutaneous abscesses
• Osteomyelitis ^[2]
• Prostatitis
• Epididymoorchitis
• tubo-ovarian abscess ^[3][4].
• Side effects from the treatment drugs such as Amphotericin B

Extra-pulmonary manifestations usually require a longer overall duration of treatment. The cases that do relapse after treatment, usually respond well to a second treatment course.
Mortality rate in treated cases is as follows:

• 0-2% in treated cases among immunocompetent patients
• 29% in immunocompromised patients
• 40% in the subgroup of patients with AIDS
• 68% in patients presenting as acute respiratory distress syndrome (ARDS)

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