Marked elevation of the serum ferritin is highly specific for disseminated histoplasmosis in AIDS

AST to ALT Ratio is elevated in disseminated histoplasmosis as compared to localized pulmonary disease and other endemic mycoses

Severe pulmonary or disseminated histoplasmosis often necessitates presumptive antifungal treatment while awaiting definitive diagnosis. Histoplasma antigen assays have improved sensitivity but results may lag up to 7 days. In order to increase diagnostic certainty, "soft clues" may be looked for in laboratory and radiologic data, such as elevated alkaline phosphatase or ferritin levels and findings of mediastinal adenopathy or hepatosplenomegaly. To determine if elevated aspartate aminotransferase (AST) to alanine aminotransferase (ALT) ratio is specific to histoplasmosis or a non-specific marker for disseminated fungal infection or sepsis in general, we retrospectively examined records of all patients diagnosed with an endemic fungal infection (EFI) at Rush University Medical Center from January of 1997 to October of 2012, and a cohort of septic patients with elevated liver enzymes. We identified 90 cases of EFIs during the study period that met all inclusion criteria (Histoplasma 21, Blastomyces 56, Coccidioides 12, Paracoccidioides 1). We also evaluated 10 control patients with bacterial sepsis. The mean ratio of AST to ALT in patients with disseminated histoplasmosis was 2.69 (95% CI:1.22, 4.16) while for other EFIs, the mean ratio ranged from 0.38 to 1.14 with disseminated coccidioidomycosis and blastomycosis respectively (P < 0.0001). The ratio in patients with bacterial sepsis was 0.84. We propose the use of the AST/ALT ratio as a clinical "soft clue" suggestive of disseminated histoplasmosis in the appropriate host, and to possibly distinguish cross reactivity of the Histoplasma antigen assay with other EFIs.

Causes of hyperferritinaemia classified by HIV status in a tertiary-care setting in South Africa

This study included all patients, with known HIV-1 status, admitted to hospital over a 5-year period with serum ferritin values exceeding 1500 μg/l. Markedly elevated serum ferritin levels are associated with a host of causes which poses a diagnostic dilemma, as the aetiology is often highly dependent on local epidemiology. We evaluated patients' records retrospectively to determine underlying causes of possible hyperferritinaemia. Aetiologies associated with hyperferritinaemia varied significantly depending on HIV-1 status. In patients infected with the HIV-1 virus, infectious causes predominated with Mycobacterium tuberculosis accounting for more than 50% of the patient population with an odds ratio of 17·98 (95% confidence interval 8·31–38·88) in HIV-positive compared to HIV-negative patients. Of the HIV-1-negative patients, hereditary haemochromatosis accounted for less than 2% of patients and chronic renal failure was the most common diagnosis. The finding of hyperferritinaemia should prompt determination of HIV-1 status, as this impacts significantly on aetiological epidemiology. In HIV-1-positive patients, aggressive investigation for mycobacterial infection should be undertaken in cases of combined hyperferritinaemia and positive HIV-1 serology.

Histoplasmosis

The diagnosis of histoplasmosis depends on recognition of the different clinical manifestations of infection, accompanied by knowledge of the accuracy and limitations of tests used for diagnosis of fungal infections. Although most infections are asymptomatic, histoplasmosis can be severe, or even fatal, in patients who have experienced a heavy exposure, have underlying immune defects, or develop progressive disease that is not recognized and treated. This article provides an up-to-date clinical review of histoplasmosis, focusing on recognition, diagnosis, and management.

Histoplasmosis. Experience during outbreaks in Indianapolis and review of the literature

Histoplasmosis remains a common infection in endemic regions of North America and Latin America, causing a broad spectrum of clinical findings. Experience during recurrent outbreaks in Indianapolis has shown the importance of immunosuppressive conditions including the acquired immunodeficiency syndrome (AIDS) as a risk factor for disseminated disease and expanded our knowledge of the common clinical manifestations. Pericarditis, rheumatologic manifestations, esophageal compression, and sarcoidlike manifestations were found to be relatively common findings in histoplasmosis. These studies have established the useful role of serologic testing and have led to the discovery of antigen testing for diagnosis of histoplasmosis. This experience also has offered the opportunity to examine the outcome of treatment in persons with AIDS, contributing to studies that have found itraconazole to be an excellent alternative to amphotericin B in persons with mild or moderately severe infection.