Histoplasmosis: Difference between revisions
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==Background== | ==Background== | ||
*Fungal infection caused by Histoplasma capsulatum<ref>Lowell JR. Diagnosis of histoplasmosis. Ann Intern Med. Feb 1983;98(2):260</ref> | *Fungal infection caused by Histoplasma capsulatum<ref>Lowell JR. Diagnosis of histoplasmosis. Ann Intern Med. Feb 1983;98(2):260</ref> | ||
*Endemic to the Ohio, Missouri, and Mississippi River valleys in the United States<ref>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</ref> | *Endemic to the Ohio, Missouri, and Mississippi River valleys in the United States<ref>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</ref> | ||
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*Activities associated with high-level exposure include spelunking, excavation, and demolition of old buildings | *Activities associated with high-level exposure include spelunking, excavation, and demolition of old buildings | ||
==Pathogenesis== | [[File:Histo-xray.png|thumb|Histoplasmosis after return from Pennsylvania, United States]] | ||
===Pathogenesis=== | |||
*Infection occurs via inhalation<ref>“Histoplasmosis.” CDC. (2014, Sept. 25) Web 4 Dec. 2014. http://www.cdc.gov/fungal/diseases/histoplasmosis</ref> | *Infection occurs via inhalation<ref>“Histoplasmosis.” CDC. (2014, Sept. 25) Web 4 Dec. 2014. http://www.cdc.gov/fungal/diseases/histoplasmosis</ref> | ||
*In immunocompetent patients: | *In immunocompetent patients: | ||
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*[[Tuberculosis]] | *[[Tuberculosis]] | ||
==Workup== | ==Diagnosis== | ||
===Workup=== | |||
*CXR | *CXR | ||
**Normal in 40-70% of cases | **Normal in 40-70% of cases | ||
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**Focal pulmonary infiltrates with light exposure | **Focal pulmonary infiltrates with light exposure | ||
**Diffuse infiltrates with heavy exposure | **Diffuse infiltrates with heavy exposure | ||
*CBC | *CBC - mild anemia in chronic disease | ||
* | *Liver panel - alkaline phosphatase elevated in disseminated and chronic disease | ||
*LDH | *LDH - elevated in AIDS patients with disseminated disease | ||
*Definitive diagnosis by: | *Definitive diagnosis by: | ||
**Sputum cultures | **Sputum cultures | ||
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*Further imaging if concerned for specific organ involvement in disseminated disease (Head CT, Abdominal CT or [[Lumbar puncture]]) | *Further imaging if concerned for specific organ involvement in disseminated disease (Head CT, Abdominal CT or [[Lumbar puncture]]) | ||
== | ==Management== | ||
===Acute Pulmonary Histoplasmosis=== | ===Acute Pulmonary Histoplasmosis=== | ||
*Do not treat if asymptomatic | *Do not treat if asymptomatic | ||
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*Admit severe symptoms or symptomatic immunocompromised patients | *Admit severe symptoms or symptomatic immunocompromised patients | ||
== | ==See Also== | ||
==References== | |||
<references/> | <references/> | ||
[[Category:ID]] | [[Category:ID]] |
Revision as of 11:41, 22 August 2015
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
Pathogenesis
- Infection occurs via inhalation[4]
- In immunocompetent patients:
- Phagocytes and epithelial cells eventually organize and form granulomas that go on to fibrose and calcify
- In immunocompromised patients:
- The infection is not contained and can disseminate
Clinical Features
- Disease manifestation depends on intensity of exposure, immune status, and underlying lung architecture
Acute Pulmonary Histoplasmosis
- 90% asymptomatic, and usually self-limited
- Symptoms 1-4 weeks after exposure and consist of flu-like illness[5]
- 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[6]
- 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
Diagnosis
Workup
- CXR
- Normal in 40-70% of cases
- Pneumonitis with hilar adenopathy
- Focal pulmonary infiltrates with light exposure
- Diffuse infiltrates with heavy exposure
- CBC - mild anemia in chronic disease
- Liver panel - alkaline phosphatase elevated in disseminated and chronic disease
- LDH - elevated in AIDS patients with disseminated disease
- Definitive diagnosis by:
- Sputum cultures
- Blood cultures
- Antibody testing
- Serum/urine antigen testing
- Further imaging if concerned for specific organ involvement in disseminated disease (Head CT, Abdominal CT or Lumbar puncture)
Management
Acute Pulmonary Histoplasmosis
- Do not treat if asymptomatic
- Not progressive, resolves without tx, only rarely reactivates
Progressive Disseminated Histoplasmosis
- Pulmonary cases: Itraconazole x 6-12 weeks[7]
- Severe disease: Amphotericin B x 1 week then Itraconazole x 1 year[8]
- Surgical intervention may be necessary in some cases
Chronic Pulmonary Histoplasmosis
- Itraconazole x 1 year
Disposition
- Discharge asymptomatic cases
- Discharge mildly symptomatic immunocompetent patients with primary care follow up
- Admit severe symptoms or symptomatic immunocompromised patients
See Also
References
- ↑ 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
- ↑ “Histoplasmosis.” CDC. (2014, Sept. 25) Web 4 Dec. 2014. http://www.cdc.gov/fungal/diseases/histoplasmosis
- ↑ http://www.ncbi.nlm.nih.gov/pubmed/24528944
- ↑ http://www.ncbi.nlm.nih.gov/pubmed/23664715
- ↑ 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