Disseminated histoplasmosis

Disseminated histoplasmosis, also known as progressive disseminated histoplasmosis, is a severe form of histoplasmosis infection typically seen in immunosuppressed patients, especially in the setting of HIV infection. It results from haematogeneous dissemination of the infection, involving multiple organs and systems and associating a high mortality¹.

Terminology

Although it is sometimes referred to as extrapulmonary histoplasmosis, lung involvement is one of the commonest manifestations of this condition².

Epidemiology

Dissemination of the disease is fairly uncommon and may occur in 1 in 2000 acute infections³.

Risk factors

• HIV infection, especially with less than 150 cells/μL CD4^1,4

• Immunosuppressive medications⁴

• Biologic agents (infliximab, etanercept)³

• Immune disorders (idiopathic CD4 lymphocytopenia, Job's syndrome, common variable immunodeficiency)

• Extremes of ages

Clinical presentation

Clinical presentation includes systemic symptoms such as fever, weight loss and fatigue and local systems depending on the organs involved, with frequent progressive shortness of breath and diarrhoea^1,3.

Physical examination may reveal hepatoesplenomegaly, lymphadenopathy and skin and oral lesions¹.

Location

• Lungs: parenchymal disease².

• Gastrointestinal: any site of the digestive tube can be involved, with potential bleeding or perforation^1,4.

• Liver and spleen: haemophagocytic lymphohistiocytosis with macrophage activation syndrome¹.

• Kidneys: granulomatous nephritis¹.

• Adrenal glands: adrenal insuficciency^1,3.

• Central nervous system: meninges, brain or spinal cord lesions¹.