<p>Medical Mycology (Biol 4849) Summer 2007</p><p>Dr. Cooper</p><p>Histoplasmosis</p><p>Synonyms: African histoplasmosis, Histoplasma capsulatum, Histoplasma duboisii, North American histoplasmosis, Darling disease</p><p>• Histoplasmosis </p><p>• intracellular myotic infection of the reticuloendothelial system, which is part of the immune system, such as lymph nodes</p><p>• Mississippi- Ohio River Valley in the U.S. is the major endemic region</p><p>• Africa, Australia, India, and Malaysia are also endemic regions</p><p>• Histoplasma capsulatum is known as North American Histoplasmosis </p><p>• Histoplasma duboisii is known as African Histoplasmosis </p><p>• Presentation of Disease</p><p>– “coin” like lesions on histocytes and reticuloendothelical cells</p><p>– Pulmonary nodules are circular calcification which makes them visible on chest x-rays</p><p>– Histoplasma capulatum yeast are found in the center of the lesions</p><p>• Case Report 1</p><p>• CT scan of the cerebrum revealed a great dilatation of the cerbral ventricles due to the obstruction of the sylvian aqueduct.</p><p>• CT scan of abdominal organs revealed ascities and retroperitoneal lymphadenopathies.</p><p>• CSF showed decreased glucose and elevated protein values.</p><p>• After two weeks after admission, pt. receive antifungal drugs starting with amphotericin and fluconazole.</p><p>• Pt. expires eight day later.</p><p>• Autopsy reveals edema and areas of bronchopneumonic consolidations in both lungs; enlarged hilar nodes, which constricted the main bronchus; the abdominal lymph nodes were also swollen; there was also hepatosplenomegaly; signs of leptomeningitis and many small areas of inflammation in the brain parenchyma. • Case Report 2</p><p>• May 2007:</p><p>• Upon examination, cervical lymphadenopathy and hepatomegaly was noted. The lesion mimic cancer.</p><p>• Elective surgery was performed.</p><p>• Histopathological examination of the resected segment of the sigmoid colon revealed small oval, narrow-based budding yeast. Suggestive of H. capsulatum.</p><p>• June 2007:</p><p>• Patient was treated with I.V. amphotericin </p><p>• Significance: Histoplasmosis has been reported both in immunocompetent as well as immunocomporomised patients with dissemenated forms being more common in the latter group.</p><p>• In HIV positive patients the prevalence of histoplasmosis varies from 5% - 32% depending on the endemicity of the disease.</p><p>• There was no prior clinical suspicion of HIV infection in patient.</p><p>• There was involvement of only the sigmoid colon and there was no associated hepatosplenomegaly, lymphadenopathy, or orophyaryngeal ulcer.</p><p>• H. capsulatum may present as carcinoma. Good differential diagnosis and hx may help to avoid making the same mistake.</p><p>• Case Report 3 </p><p>Sobrinho FP., Negra MD., Queiroz W., et al. “Histoplasmosis of the Larynx.” Rev Bras Otorrinolaringol. 2007; 73(6): 857-61. Article acquired on June17, 2008 from Pub Med.</p><p>• Pt. presented hoarseness, progressive dysphagia, and weight loss.</p><p>• Pt. has hx of HIV since 1996.</p><p>• Laryngoscopy showed white necrotic lesion spread throughout his larynx, edema and exophytic lesion in the upper right border of the epiglottis.</p><p>• There was no lesion on the skin.</p><p>• Occurrence is high in immunosuppressed and elderly patients, and more commonly in men. • Fever, weight loss, asthenia, liver and spleen enlargement and oral mucosa lesions are very common.</p><p>• Infection can spread to other organs such as bone marrow, lymph nodes, adrenal glands, G.I. tract, tongue and oral mucosa. </p><p>• Acute pulmonary histoplasmosis usually occurs in children below one year of age or in severe immunosuppresessed patients.</p><p>• Weight loss, fever, liver and spleen enlargement , shock, respiratory failure and disseminated intra-vascular coagulation (DIVC) are common.</p><p>• Histopathology</p><p>• Infection is acquired through the inhalation of histoplasma capsulatum microcondia, which is the spores of this fungi</p><p>• Lungs, bones, and skin are the most frequent affected site from this fungus</p><p>• It may coexist with other mycoses or even diseases, such as emphysema and tuberculosis</p><p>• Causative Organism: </p><p>– Histoplasma capsulatum </p><p>• Clinical Manifestations</p><p>• 95% of cases of histoplasmosis are unapparent or benign</p><p>• 5% have chronic progressive lung disease, chronic cutaneous or systemic disease, or fatal systemic disease</p><p>• The disease may mimic tuberculosis</p><p>Symptoms:</p><p>• Lymph nodes- inflamed lymph nodes</p><p>• Adrenal Glands- enlargement </p><p>• Central Nervous System- chronic meningitis</p><p>• GI tract- oral ulcers, small bowel micro and macro ulcers</p><p>• Eyes- inflamed inner eye</p><p>• Skin- papular to nodular rash </p><p>• Genitourinary tract- bladder ulcer, penile ulcers • Laboratory Aspects</p><p>Virulence Factors:</p><p>• In most cases, inhalation of microconidia, which in turn germinates into yeasts within the lung is the cause of virulence</p><p>Diagnosis:</p><p>• Skin scrapings examined using 10% KOH</p><p>• Body fluids, such as blood, should be centrifuged and examined </p><p>• Tissues should be stained using a Gram stain and examined </p><p>• Epidemiology and Ecology</p><p>• Ecology</p><p>- found in moderate climates, humidity, and soil characteristics</p><p>- bird and bat excrement enhances the growth of the organism in soil by accelerating sporulation </p><p>• Epidemiology</p><p>- Infects mostly immunosuppressed individuals, children less than 2 years old, and elderly people use of broad spectrum antibiotics</p><p>- air currents carry spores which exposes individuals who breath in the contaminated air</p><p>• Treatment and Prevention</p><p>Treatment </p><p>• Long-term therapy with antifungal agents at increasing doses until resolution of symptoms, such as amphotericin B, fluconazole, and intraconazole </p><p>• Surgical procedures to remove the ulcer may also be done</p><p>Prevention </p><p>• No direct away to avoid this fungal infection because it is airborne</p><p>• Avoid areas with accumulations of bird or bat droppings. </p><p>• Before starting an activity having a risk for exposure to H. capsulatum, consult the NCID Document Histoplasmosis: Protecting Workers at Risk • References</p><p>• “Histoplasmosis.” http://www.mycology.adelaide.edu.au/Mycoses/ </p><p>Dimorphic_systemic/Histoplasmosis/index Article acquired on June</p><p>16, 2008 from Mycology Online.</p><p>• Histoplasmosis.” http://www.doctorfungus </p><p>Org/mycoses/human/histo/histoplasmosis_index.htm Article acquired on June 16, 2008 from Doctor Fungus.</p><p>• “Histoplasmosis Due to Histoplasma Capsulatum.” http://www.doctorfungus </p><p>Org/mycoses/human/histo/histoplasmosis_c.htm Article acquired on</p><p>June 16, 2008 from Doctor Fungus.</p><p>• Histoplasmosis Due to Histoplasma Duboisii.” http://www.doctorfungus </p><p>Org/mycoses/human/histo/histoplasmosis_d.htm Article acquired on</p><p>June 16, 2008 from Doctor Fungus.</p><p>• Sehgal S., Chawla R., Loomba PS, Mishra B. “Gastrointestinal Histoplasmosis Presenting As Colonic Pseudo-tumour.”</p><p>Indian Journal of Medical Microbiology. 2008; 26(2) 187-189. Article acquired on June17, 2008 from Pub Med.</p><p>• Severo LC., Zardo IB., Roesch W., and Hartmann AA. “Acute Disseminated</p><p>Histoplasmosis In Infancy in Brazil: Report of a case and Review.”</p><p>Rev Iberoam Micol. 1998; 15:48-50. Article acquired on June17, 2008 from Pub Med.</p><p>• Sobrinho FP., Negra MD., Queiroz W., et al. “Histoplasmosis of the Larynx.”</p><p>Rev Bras Otorrinolaringol. 2007; 73(6): 857-61. Article acquired on June17, 2008 from Pub Med.</p>