Histoplasmosis
Revision as of 15:01, 1 December 2014 by Vincent Chan (talk | contribs) (→Acute Pulmonary Histoplasmosis)
Background
- Fungal infection caused by Histoplasma capsulatum[1]
- Endemic to the Ohio, Missouri, and Mississippi River valleys in the United States[2]
Clinical Features
Acute Pulmonary Histoplasmosis
- 90% asymptomatic, and usually self-limited
- Fever/chills
- Headache
- Malaise
- Myalgias
- Abdominal pain
- Joint pains
- Dyspnea
- Cough
- Hemoptysis
- Hilar/mediastinal lymphadenopathy
Chronic Pulmonary Histoplasmosis
- Mostly older patients with underlying lung disease
- Cough
- Weight loss
- Fever
- Malaise
- Sometimes hemoptysis, sputum production, dyspnea
- CXR may show:
- Upper lobe infiltrates
- Fibrosis, scarring
- Cavitations
Progressive Disseminated Histoplasmosis
- Seen in immunocompromised patients
- Acute form: fever, cough, weight loss, malaise, dyspnea, +/-CNS involvement
- Subacute form: wide variety of symptoms depending on affected organ system
- Chronic form: constitutional sx
Mediastinitis
- Enlarged lymph nodes undergo necrosis
- This leads to granulomatous mediastinitis
Differential Diagnosis
- Aspergillosis
- Blastomycosis
- Carcinoid Lung Tumors
- Chlamydophila psittaci
- Coccidioidomycosis
- Legionella pneumonias
- Lung Cancer, Small Cell
- Lymphoma, Mediastinal
- Mediastinal Cysts
- Lung Abscess
- Mycoplasma Infections
- Pancoast Syndrome
- Pneumococcal Infections
- Pneumocystis Carinii Pneumonia
- Aspiration Pneumonia
- Pneumonia
- Sarcoidosis
- Tuberculosis
Workup
- CBC (mild anemia in chronic disease)
- Alkaline phosphatase (elevated in disseminated and chronic disease)
- LDH (elevated in AIDS patients with disseminated disease)
- Sputum cultures
- Blood cultures
- Antibody testing
- Serum/urine antigen testing
- CXR
- Further imaging if concerned for specific organ involvement in disseminated disease (head CT, abdominal CT)
Treatment
Acute Pulmonary Histoplasmosis
- Do not treat if asymptomatic
- Itraconazole x 6-12 weeks[3]
- Severe disease: Amphotericin B x 1 week then Itraconazole x 1 year[4]
Chronic Pulmonary Histoplasmosis
- Itraconazole x 1 year
Progressive Disseminated Histoplasmosis
- See above medical therapy
- Surgical intervention may be needed for some end organ involvement
Sources
- ↑ Lowell JR. Diagnosis of histoplasmosis. Ann Intern Med. Feb 1983;98(2):260
- ↑ Outbreak of histoplasmosis among travelers returning from El Salvador--Pennsylvania and Virginia, 2008. MMWR Morb Mortal Wkly Rep. Dec 19 2008;57(50):1349-53
- ↑ Wheat LJ, Freifeld AG, Kleiman MB, et al. Clinical practice guidelines for the management of patients with histoplasmosis: 2007 update by the Infectious Diseases Society of America. Clin Infect Dis. 2007;45:807-825
- ↑ Hospenthal DR, Becker SJ. Update on Therapy for Histoplasmosis. Infect Med. April 13 2009;26:121-124