NCLEX Review Guide: Histoplasmosis

Disease Overview

• Histoplasmosis is a systemic fungal infection caused by Histoplasma capsulatum, commonly found in soil contaminated with bird or bat droppings.
• The fungus becomes airborne when contaminated soil is disturbed, leading to inhalation of spores that primarily affect the respiratory system.
• Most infections are asymptomatic or mild, but can become severe in immunocompromised patients or with heavy exposure.

Acute Pulmonary Histoplasmosis

• Symptoms appear 3-17 days after exposure and resemble flu-like illness with fever, chills, headache, and myalgia.
• Respiratory symptoms include dry cough, chest pain, and dyspnea that may progress to productive cough.
• Chest X-ray typically shows bilateral infiltrates and hilar lymphadenopathy.

Laboratory & Imaging Studies

• Histoplasma antigen test (urine/serum) is the most rapid and reliable diagnostic method, especially for disseminated disease.
• Fungal cultures from sputum, blood, or tissue provide definitive diagnosis but take 2-4 weeks for results.
• Chest CT may reveal mediastinal lymphadenopathy and pulmonary nodules more clearly than chest X-ray.

Pharmacological Management

1. Mild cases often resolve spontaneously without treatment in immunocompetent patients.
2. Itraconazole is the first-line oral antifungal for mild-to-moderate cases requiring treatment.
3. Amphotericin B is reserved for severe, life-threatening, or disseminated infections.
4. Treatment duration is typically 6-12 weeks for pulmonary disease.

• ☐ Can I identify the geographic areas where histoplasmosis is endemic?
• ☐ Do I understand the difference between histoplasmosis and tuberculosis transmission?
• ☐ Can I recognize the typical presentation and timeline of acute histoplasmosis?
• ☐ Do I know the first-line treatment for mild-to-moderate cases?
• ☐ Can I identify high-risk exposure activities for histoplasmosis?