Histoplasmosis
Revision as of 23:53, 11 December 2014 by Jmnelson86 (talk | contribs) (additions to existing information)
Background
- Fungal infection caused by Histoplasma capsulatum[1]
- Endemic to the Ohio, Missouri, and Mississippi River valleys in the United States[2]
- Exposure from disruption of soil containing organisms leads to aerosolization[3]
- Activities associated with high-level exposure include spelunking, excavation, and demolition of old buildings[4]
Clinical Features
- Disease manifestation depends on intensity of exposure, immune status, and underlying lung architecture[5]
Acute Pulmonary Histoplasmosis
- 90% asymptomatic, and usually self-limited
- Symptoms 1-4 weeks after exposure and consist of flu-like illness
- Fever/chills
- Headache
- Malaise
- Myalgias
- Abdominal pain
- Arthralgias
- Dyspnea
- Cough, hemoptysis
- Hilar/mediastinal lymphadenopathy on CXR
Chronic Pulmonary Histoplasmosis
- Mostly older patients or smokers with underlying structural lung disease
- Symptoms:
- Cough
- Weight loss
- Low-grade fever
- Malaise
- Night sweats
- Sometimes hemoptysis, sputum production, dyspnea
- CXR may show:
- Upper lobe infiltrates
- Fibrosis, scarring
- Cavitations
Progressive Disseminated Histoplasmosis
- Seen in immunocompromised patients
- SIRS
- Acute form:
- Diffuse interstitial or reticulonodular lung infiltrates
- Respiratory failure
- Coagulopathy
- Multiorgan failure
- Subacute form depends on focal organ system affected:
- Fever
- Weight loss
- Hepatosplenomegaly
- Meningitis, brain lesions
- Mucosal or GI ulcerations
- Adrenal insufficiency
- Pericarditis
- Chronic form: constitutional sx
Mediastinitis
- Enlarged lymph nodes that may undergo necrosis
- This leads to granulomatous mediastinitis
- Can lead to:
- Superior vena cava syndrome
- Obstruction of pulmonary vessels
- Airway obstruction
- Recurrent pneumonia
- Hemoptysis
- Respiratory failure
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[6]
- Severe disease: Amphotericin B x 1 week then Itraconazole x 1 year[7]
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
- ↑ Hage, Chadi A., and L. Joseph Wheat. "Chapter 199. Histoplasmosis." Harrison's Principles of Internal Medicine, 18e. Eds. Dan L. Longo, et al. New York, NY: McGraw-Hill, 2012. n. pag. AccessMedicine. Web. 4 Dec. 2014
- ↑ Hage, Chadi A., and L. Joseph Wheat. "Chapter 199. Histoplasmosis." Harrison's Principles of Internal Medicine, 18e. Eds. Dan L. Longo, et al. New York, NY: McGraw-Hill, 2012. n. pag. AccessMedicine. Web. 4 Dec. 2014
- ↑ Hage, Chadi A., and L. Joseph Wheat. "Chapter 199. Histoplasmosis." Harrison's Principles of Internal Medicine, 18e. Eds. Dan L. Longo, et al. New York, NY: McGraw-Hill, 2012. n. pag. AccessMedicine. Web. 4 Dec. 2014
- ↑ 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