Histoplasmosis

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Presentation :

• Histoplasmosis most commonly presents with acute respiratory symptoms.
  • Other presentations include disseminated infections (immunosuppressed host), chronic pulmonary symptoms, rheumatologic symptoms, pericarditis, and sclerosing mediastinitis.

Pathophysiology :

• Caused by Histoplasma capsulatum
• Acquired by inhalation of conidia, this organism primarily produces asymptomatic pulmonary infection.

Diagnostic Testing:

• The Histoplasma urinary antigen assay has a sensitivity and specificity of greater than 85% in acute and disseminated infection but less than 50% in chronic infection.
• Identification by tissue culture can be a lengthy process but is indicated for suspected cases in which the serum antibody and urinary antigen assay result is negative.

Treatment :

• Asymptomatic and mild pulmonary histoplasmosis typically resolve without treatment.
• Itraconazole is the agent of choice; therapy duration is 6 to 12 weeks for acute infection and 12 months for chronic cavitary pulmonary infection.
• For severe lung disease and disseminated infection, liposomal amphotericin B should be used initially, followed by de-escalation to oral itraconazole.

Prognosis:

References: