Histoplasmosis - chronic pulmonary Health Article

Definition

Chronic pulmonary histoplasmosis is a long-term respiratory infection caused by breathing the spores of the fungus, Histoplasma capsulatum.

See also:

• Acute pulmonary histoplasmosis
• Disseminated histoplasmosis
• Skin lesion of histoplasmosis

Alternative Names

Chronic cavitary histoplasmosis

Causes, incidence, and risk factors

Histoplasma capsulatum is a fungus found in the soil of the central and eastern United States (especially Mississippi and Ohio river valleys), eastern Canada, Mexico, Central America, and South America.

The infection occurs when a person breathes in the reproducing parts of the fungus, called spores. Those who have a healthy immune system usually do not have symptoms, or only mild ones.

This "acute" infection does not last, but can leave a person with small scars (granulomas). These scars are sometimes difficult to distinguish from growths in the lung.

However, the infection can cause severe illness right away, or redevelop years after the first exposure, if a person's immune system is weakened by:

• Cancer
• Chemotherapy
• Immune-suppressing drugs
• HIV infection

Risk factors for chronic pulmonary histoplasmosis include:

• Living in or traveling to central or eastern United States
• Exposure to soil or particles contaminated with droppings of chickens, bats, or blackbirds
• Pre-existing COPD
• Weakened immune system, such as in people who have AIDS

Symptoms

• Chills
• Cough that brings up mucus or pus
• Fever
• Joint stiffness
• Shortness of breath
• Skin involvement (erythema nodosum)
• Unintentional weight loss

Signs and tests

Tests that may be used to diagnose chronic pulmonary histoplasmosis include:

• Biopsy of infected tissue, such as open lung biopsy or bone marrow biopsy
• Bronchoscopy with transbronchial biopsy or bronchoalveolar lavage
• CBC
• Chest CT scan
• Chest x-ray
• Histoplasma complement fixation titer
• Histoplasma urinary antigen test
• Immunodiffusion test
• Sputum culture and stain

Treatment

The doctor will prescribe antifungal medications to control the infection within the lung.