Histoplasmosis

Scar carcinomas of the lung of the nonmudnous (Clara cell) type arising around an old scar due to histolasmosis granuloma were found in a histoplasmosis endemic area of eastern Kentucky (Yoneda 1990). 

In wild rats, Emmons and Ashburn (1948) found granulomas usually situated in the Uver and spleen, but also in lungs and adrenals. From Brazil Silva and Paula (1956) described natural infections of rat. 

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Fungal (histoplasmosis, coccidioidomycosis, cryptococcosis, Blastomyces dermatitidis infection)... 

Two of the most common endemic fungal infections (histoplasmosis and North American blastomycosis) are found in... 

Response to antifungal therapy may be slow in patients with a prolonged history of infection or severe manifestations. However, gradual improvements in symptoms and reduction in fever are indicators of response to antifungal therapy. For histoplasmosis and coccidioidomycosis, decreasing antigen titers are also indicative of response to antifungal therapy.1... 

Wheat J, Sarosi G, McKinsey D, et al. Practice guidelines for the management of patients with histoplasmosis. Clin Infect Dis 2000 30 688-695. 

Albumin 0.1-1 IV immunosuppressives delivery infestation of the RES (e.g., histoplasmosis, typhoid) [14C]Mercaptopurine-8-hydrate... 

Suggested Alternatives for Differential Diagnosis Abdominal aneurysm, aortic dissection, pleural effusion, subarachnoid hemorrhage, superior vena cava syndrome, hantavirus pulmonary syndrome, mediastinitis, fulminate mediastinal tumors pneumonia, gastroenteritis, meningitis, ecthyma, rat bite fever, spider bite, leprosy, plague, tularemia, coccidioidomycosis, diphtheria, glanders, histoplasmosis, psittacosis, typhoid fever, and rickettsial pox. 

Suggested Alternatives for Differential Diagnosis Influenza, infectious mononucleosis, hepatitis, leptospirosis, infective endocarditis, malaria, tuberculosis, typhoid fever, cryptococcosis, histoplasmosis, ankylosing spondylitis and undifferentiated spondyloarthropathy, collagen vascular disease, chronic fatigue syndrome, malignancy, and osteomyelitis. 

Suggested Alternatives for Differential Diagnosis Bartonellosis, brucellosis, other causes of encephalitis, coxsackieviruses, cryptococcosis, cysticercosis, cytomegalovirus, histoplasmosis, legionellosis, leptospirosis, listeria, lyme disease, malaria, rabies, tuberculosis, mumps, stroke, metabolic encephalopathy, Reye syndrome, Bartonella infection, Naegleria infection, Ebstein-Barr virus, prion disease, toxic ingestions, and AIDS. 

Lenhart, Steven W., Millie P. Schafer, Mitchell Singal, and Rana A. Hajjeh. Histoplasmosis Protecting Workers at Risk. Rev. ed. Centers for Disease Control and Prevention, December 2004. 

Histoplasmosis is caused by inhalation of dust-borne microconidia of the dimorphic fungus Histoplasma capsulatum. 

In patients exposed to a large inoculum and in immunocompromised hosts, progressive illness, disseminated histoplasmosis, occurs. The clinical severity of the diverse forms of disseminated histoplasmosis (Table 38-1) generally parallels the degree of macrophage parasitization observed. 

Acute (infantile) disseminated histoplasmosis is seen in infants and young children and (rarely) in adults with Hodgkin s disease or other lympho-... 

Acute pulmonary histoplasmosis Asymptomatic or mild disease... 

Disseminated histoplasmosis Acute (Infantile) Subacute Progressive histoplasmosis (immunocompetent patients and immunosuppressed patients without AIDS) 0.02-0.05 Disseminated histoplasmosis Untreated mortality 83% to 93% relapse 5% to 23% in non-AIDS patients therapy is recommended tor all patients Nonimmunosuppressedpatients Ketoconazole 400 mj day orally x 6-12 months or amphotericin B 35 mg/kg IV Immunosuppressed patients (non-AIDS) or endocarditis or CNS disease Amphotericin B >35 mg/kg x 3 months followed by fluconazole or itraconazole 200 mg orally twice daily x 12 months Life-threatening disease Amphotericin B 0.7-1 mg/kg/day IV for a total dosage of 35 mj kg over 2-4 months once the patient is afebrile, able to take oral medications, and no longer requires blood pressure or ventilatory support therapy can be changed to itraconazole 200 mg orally twice daily for 6-18 months Non-life-threatening disease Itraconazole 200-400 mg orally daily for 6-18 months fluconazole therapy 400-800 mg daily should be reserved for patients intolerant to itraconazole, and the development of resistance can lead to relapses... 

Data from Deepe CS. Histoplasma capsulatum. In Mandell CL, Bennett JE, Dolin % eds. Principles and Practice of Infectious Diseases, 6th ed. Philadelphia, PA Churchill Livingstone, 2005 3012-3026 Wheat J, Sarosi C, McKinsey D, et al. Practice guidelines for the management of patients with histoplasmosis. Oin Infect Dis 2000 30 688-695 Wheat U, Kauffman CA. Histoplasmosis. Infect Dis Oin North Am 2003 17(1) 1-19. 

Most adults with disseminated histoplasmosis demonstrate a mild, chronic form of the disease. Untreated patients are often ill for 10 to 20 years, with long asymptomatic periods interrupted by relapses characterized by weight loss, weakness, and fatigue. 

In most patients, serologic evidence remains the primary method in the diagnosis of histoplasmosis. Results obtained from complement fixation, immunodiffusion, and latex antigen agglutination antibody tests are used... 

In the AIDS patient with progressive disseminated histoplasmosis, the diagnosis is best established by bone marrow biopsy and culture, which yield positive cultures in 90% of patients. 

Recommended therapy for the treatment of histoplasmosis is summarized in Table 38-1. 

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