Pulmonary Histoplasmosis

Abstract

Pulmonary histoplasmosis is an important cause of morbidity in the United States. Several outbreaks of acute pulmonary histoplasmosis have been linked to potentially preventable environmental exposures. Progressive disseminated histoplasmosis, which is seen frequently in the growing population of immunocompromised hosts, often presents with prominent pulmonary manifestations and is more commonly encountered in hospitalized patients than acute, subacute, or chronic pulmonary histoplasmosis. A battery of diagnostic studies including serology, antigen, cytology/histopathology, and culture should be obtained in suspected cases of histoplasmosis. The yield of antigenuria detection is highest when the multiple body fluids are tested; the level of antigenuria correlates with severity of disease. Amphotericin B is the treatment of choice for severe pulmonary or disseminated histoplasmosis, and itraconazole is effective for mild to moderately severe infection. Posaconazole exhibits promise as a salvage agent. Antifungal prophylaxis is not routinely recommended for at-risk populations. Measures to minimize environmental contamination may reduce the risk of epidemic-type acute pulmonary histoplasmosis related to high-risk exposures.

Isolated Pancreatic Histoplasmosis: An Unusual Suspect of Pancreatic Head Mass in an Immunocompetent Host

“…This pattern of negative antigen testing and tissue cultures along with a positive serology is more likely to be seen in an immunocompetent state where the immune system will result in a low fungal burden. 9,10 Immunocompromised hosts, on the other hand, are more likely to have higher fungal burden with positive antigen tests and culture results and a negative serology. 6,11 Itraconazole is considered the treatment of choice in noncritically ill patients with histoplasmosis.…”

A Multinational Outbreak of Histoplasmosis Following a Biology Field Trip in the Ugandan Rainforest

“…Activities associated with exposure include cleaning chicken coops, bird roosts, attics, and barns; caving; excavation; construction, renovation, and demolition. 3 Histoplasma capsulatum var. duboisii mainly involves the skin, subcutaneous tissues, lymph nodes, and bones.…”

“…Its clinical manifestations vary according to host immunity and exposure intensity, ranging from asymptomatic infection (in most healthy persons exposed to a low inoculum) to life-threatening pneumonia with respiratory failure. 3,4 Between these extremes, clinical presentations include acute or subacute pulmonary disease, pericarditis, rheumatological syndromes with erythema nodosum, progressive disseminated disease, and mediastinal complications. 4 Acute pulmonary histoplasmosis (APH) in returning travelers typically presents as a flu-like illness with high-grade fever, chills, headache, nonproductive cough, pleuritic chest pain, and fatigue.…”

“…Serology tests peak approximately 4-6 weeks after the onset of infection and are typically negative in the first month, thus it is important to obtain paired acute and convalescent samples. 3 The sensitivity for acute pneumonia with diffuse infiltrates is 40%-80%. 3 Serological tests are less useful in immunosuppressed patients, of whom up to 40% do not mount a measurable antibody response.…”

“…3 The sensitivity for acute pneumonia with diffuse infiltrates is 40%-80%. 3 Serological tests are less useful in immunosuppressed patients, of whom up to 40% do not mount a measurable antibody response. 3 Antibodies may persist for several years after acute infection and low falsepositive complement fixation titers are attributed to previous asymptomatic infection in endemic areas.…”