A fungal disease that can affect the entire body caused by Histoplasma capsulatum, causing primary lung lesions, and hematogenous dissemination.

Inhalation of mold conidia spores or dust that has been contaminated with bat or bird droppings will cause the infection. The reservoir is in the soil, and the sources are in undisturbed places such as bat caves, roosts or old chicken houses. The condition occurs more commonly in men after prolonged exposure, and those with compromised immunity, or in infants.

Signs and symptoms of the three forms of the disease are:

• Acute primary histoplasmosis which is usually asymptomatic, or has mild symptoms of fever, cough, and malaise. Occasionally pneumonia develops.

• Progressive disseminated histoplasmosis which is spread by the blood from the lungs. The reticuloendothelial system becomes involved, with enlargement of the liver, spleen, lymphadenopathy, involvement of the bone marrow, oral ulcers, and gastrointestinal (GI) ulceration. Subacute symptoms are fatigue, weakness, and a worsening of the condition in patients with human immunodeficiency virus (HIV). Addison's disease (see Diagnostic Code: 7911 Addison's disease) is a possible, serious manifestation. This form is an opportunistic infection in acquired immunodeficiency syndrome (AIDS) patients, and severe acute pneumonia may develop.

• Chronic cavitary histoplasmosis which is manifested by lung lesions in the apex resembling the cavities seen in tuberculosis. This condition progresses to a disabling respiratory dysfunction. Another chronic, but rare form, is a fibrosing inflammation of the mediastinum which leads to circulatory compromise. In addition, histoplasmosis may be a cause of blindness.

Cultures are made from sputum, liver biopsy, blood, urine, bone marrow, lymph nodes, or mouth ulcers.

The acute primary form is self-limited, and treatment may not be required. Chronic cavitary histoplasmosis can be fatal due to a severe respiratory insufficiency. Untreated progressive disseminated histoplasmosis has a high fatality rate of 90%. The drugs of choice are amphotericin B and itraconazole.

The person being treated for histoplasmosis will require follow-up care on a regular basis for at least a year. In addition, amphotericin B is highly toxic to the kidneys, and creatinine and BUN levels should be monitored. Counseling and support may be needed to assist in coping with the long-term therapy.

• May be entitled to special monthly compensation where the Veteran has a single service-connected disability rated as 100% with additional service-connected disability or disabilities independently ratable at 60% or more, which are separate and distinct from the 100% service-connected disability and involves different anatomical segments or bodily systems. See  38 CFR 3.350(i)(1) – Special Monthly Compensation (SMC).

• Review special provisions regarding the evaluation of specific respiratory conditions under 38 CFR 4.96(a) - Rating co-existing respiratory conditions.