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Evidence-based guidelines for the management of patients with histoplasmosis were prepared by an Expert Panel of the Infectious Diseases Society of America. These updated guidelines replace the previous treatment guidelines published in 2000 (Clin Infect Dis 2000; 30:688–95). The guidelines are intended for use by health care providers who care for patients who either have these infections or may be at risk for them. Since 2000, several new antifungal agents have become available, and clinical trials and case series have increased our understanding of the management of histoplasmosis. Advances in immunosuppressive treatment for inflammatory disorders have created new questions about the approach to prevention and treatment of histoplasmosis. New information, based on publications from the period 1999–2006, are incorporated into this guideline document. In addition, the panel added recommendations for management of histoplasmosis in children for those aspects that differ from aspects in adults.

Background. The sensitivity of the MVista Histoplasma antigen enzyme immunoassay (MiraVista Diagnostics) has been evaluated in disseminated histoplasmosis in patients with AIDS and in the \"epidemic\" form of acute pneumonia. Moreover, there has been no evaluation of the sensitivity of antigenemia detection in disseminated histoplasmosis after the implementation of methods to dissociate immune complexes and denature released antibodies. The goal of this study was to determine the sensitivity of the current antigen assay in different categories of histoplasmosis. Methods. Urine and serum specimens obtained from 218 patients with histoplasmosis and 229 control subjects, including 30 with blastomycosis, were tested. Results. Antigenuria was detected in 91.8% of 158 patients with disseminated histoplasmosis, 83.3% of 6 patients with acute histoplasmosis, 30.4% of 46 patients with subacute histoplasmosis, and 87.5% of 8 patients with chronic pulmonary histoplasmosis; antigenemia was present in 100% of 31 tested cases of disseminated histoplasmosis. Among patients with disseminated cases, antigenuria was detected more often and at higher concentrations in immunocompromised patients and those with severe disease. Specificity was 99.0% for patients with nonfungal infections (n = 130) and in healthy subjects (n = 69), but cross-reactivity occurred in 90% of patients with blastomycosis. Conclusions. The sensitivity of antigen detection in disseminated histoplasmosis is higher in immunocompromised patients than in immunocompetent patients and in patients with more severe illness. The sensitivity for detection of antigenemia is similar to that for antigenuria in disseminated infection.

Background. To improve our understanding of risk factors, management, diagnosis, and outcomes associated with histoplasmosis after solid organ transplant (SOT), we report a large series of histoplasmosis occurring after SOT. Methods. All cases of histoplasmosis in SOT recipients diagnosed between 1 January 2003 and 31 December 2010 at 24 institutions were identified. Demographic, clinical, and laboratory data were collected. Results. One hundred fifty-two cases were identified: kidney (51%), liver (16%), kidney/pancreas (14%), heart (9%), lung (5%), pancreas (2%), and other (2%). The median time from transplant to diagnosis was 27 months, but 34% were diagnosed in the first year after transplant. Twenty-eight percent of patients had severe disease (requiring intensive care unit admission); 81% had disseminated disease. Urine Histoplasma antigen detection was the most sensitive diagnostic method, positive in 132 of 142 patients (93%). An amphotericin formulation was administered initially to 73% of patients for a median duration of 2 weeks; step-down therapy with an azole was continued for a median duration of 12 months. Ten percent of patients died due to histoplasmosis with 72% of deaths occurring in the first month after diagnosis; older age and severe disease were risk factors for death from histoplasmosis. Relapse occurred in 6% of patients. Conclusions. Although late cases occur, the first year after SOT is the period of highest risk for histoplasmosis. In patients who survive the first month after diagnosis, treatment with an amphotericin formulation followed by an azole for 12 months is usually successful, with only rare relapse.

Life-threatening histoplasmosis is one of the most common opportunistic infections in patients receiving tumor necrosis factor (TNF) blockers. Delays in considering the diagnosis may lead to increased morbidity and mortality. Most affected patients present with pneumonitis, usually accompanied by additional signs of progressive dissemination, or with signs of progressive dissemination alone. The diagnosis often can be promptly established using antigen detection or direct examination of bronchoalveolar lavage specimens. If histoplasmosis is diagnosed promptly, antifungal therapy is highly effective. After a favorable clinical response, the safety of both discontinuation of antifungal therapy and the resumption of TNF blocker remains undetermined. The management of the immune reconstitution inflammatory syndrome that may follow discontinuation of TNF blockers also requires investigation. Prescribers should become aware of the recognition, diagnosis, and treatment of histoplasmosis and educate recipients about decreasing their risk of exposure and both recognizing and reporting signs of early infection.

Background. Antigen detection, which has proven useful in diagnosis of disseminated histoplasmosis, has not been studied in acute pulmonary histoplasmosis (APH). Because treatment is indicated in most patients with moderately severe or severe APH, antigen detection for rapid diagnosis could be helpful. Methods. Histoplasma antigen detection was evaluated in 130 patients with APH. Results. Antigenuria was detected in 64.6%, antigenemia in 68.6%, and antibody in 64.3%. If both urine and serum specimens were tested, antigen was detected in 82.8%, of which 45.8% had antigenemia only; and if both antigen and antibody were measured, results were positive in 93.3%, of which antigen only was positive in 35.7%. Conclusions. Testing for antigenemia, antigenuria, and antibodies using the complement fixation test offers a sensitive, noninvasive method for diagnosis of APH.

Background. Many clinical scenarios have been encountered by patients who developed histoplasmosis after receiving a solid organ transplant at a large transplant center in an endemic area. Methods. Cases of posttransplantation histoplasmosis were identified by use of multiple methods, including reviews of microbiology test results, transplant databases, and billing codes. Data were obtained retrospectively. Descriptive statistics were used. Results. During the 1997–2007 study period, 3436 patients received a solid organ transplant, and 38 patients were identified as having posttransplantation histoplasmosis. Of these 38 patients, 9 were excluded from our study because the diagnosis was solely clinical. Of the remaining 29 patients, 14 had posttransplantation histoplasmosis (incidence, 1 case per 1000 person-years); 14 showed histologic evidence of histoplasmosis in the recipient or donor tissue, which was encountered unexpectedly at the time of transplantation; and 1 had histoplasmosis before receiving the transplant. Of the 14 patients who developed histoplasmosis after transplantation, 5 were heart transplant recipients, 3 were lung transplant recipients, 3 were kidney transplant recipients, 1 was a liver transplant recipient, 1 was a pancreas transplant recipient, and 1 was a kidney-pancreas transplant recipient. The median time from transplantation to diagnosis was 17 months (interquartile range, 8.1–46 months), and the median time from onset of symptoms to diagnosis 3 weeks (interquartile range, 1.9–6.5 weeks). All recipients had disseminated disease. The most common treatment was amphotericin B and itraconazole. All were cured, or still on treatment, but symptom-free. Of the 14 patients who had an explanted organ or donor tissue that showed histologic evidence of histoplasmosis, 13 (93%) were lung transplant recipients, and 1 (7%) was a liver transplant recipient. None of these patients developed active histoplasmosis, but all received prophylactic treatment. Finally, 1 patient had histoplasmosis before transplantation; he was treated with itraconazole 3 months before and after transplantation, and he did well. Conclusions. In conclusion, posttransplantation histoplasmosis is rare (1 case per 1000 transplant-person-years; 95% confidence interval, 0.6–1.7), even in endemic areas. Prognosis is good but requires protracted therapy. Patients with latent infection did not develop posttransplantation histoplasmosis when prophylaxis was used.

The effect of methamphetamine on the host response to an opportunistic pathogen has not been extensively described. Methamphetamine is a major public health and safety problem in the United States. Chronic methamphetamine abuse is associated with a 2-fold higher risk of human immunodeficiency virus infection and, possibly, additional infections. Histoplasma capsulatum is a dimorphic fungus that is endemic in the Midwest of the United States and that causes respiratory and systemic disease, particularly in individuals with impaired immunity. We showed that methamphetamine abrogates normal macrophage function, resulting in an inability to control histoplasmosis. Methamphetamine decreased phagocytosis and killing of yeast by primary macrophages by alkalization of the phagosome. Furthermore, mice that received methamphetamine prior to H. capsulatum infection were immunologically impaired, with increased fungal burden, increased pulmonary inflammation, and decreased survival. Immunosuppression by methamphetamine may be associated with deregulation of cytokines in the lungs of infected mice, aberrant processing of H. capsulatum within macrophages, and immobilization of MAC-1 receptors on the surface of macrophages that are involved in phagocytosis. Additionally, methamphetamine inhibits T cell proliferation and alters antibody production, which are important components of adaptive immunity. With use of a murine model of histoplasmosis, this study establishes that methamphetamine may alter the immune system of the host and enhance fungal pathogenesis.

In patients with moderate to severe histoplasmosis associated with AIDS, the preferred treatment has been the deoxycholate formulation of amphotericin B. However, serious side effects are associated with use of amphotericin B. To compare amphotericin B with liposomal amphotericin B for induction therapy of moderate to severe disseminated histoplasmosis in patients with AIDS. Randomized, double-blind, multicenter clinical trial. 21 sites of the U.S. National Institute of Allergy and Infectious Diseases Mycoses Study Group. 81 patients with AIDS and moderate to severe disseminated histoplasmosis. Clinical success, conversion of baseline blood cultures to negative, and acute toxicities that necessitated discontinuation of treatment. Clinical success was achieved in 14 of 22 patients (64%) treated with amphotericin B compared with 45 of 51 patients (88%) receiving liposomal amphotericin B (difference, 24 percentage points [95% CI, 1 to 52 percentage points]). Culture conversion rates were similar. Three patients treated with amphotericin B and one treated with liposomal amphotericin B died during induction (P = 0.04). Infusion-related side effects were greater with amphotericin B (63%) than with liposomal amphotericin B (25%) (P = 0.002). Nephrotoxicity occurred in 37% of patients treated with amphotericin B and 9% of patients treated with liposomal amphotericin B (P = 0.003). Liposomal amphotericin B seems to be a less toxic alternative to amphotericin B and is associated with improved survival.

Gastrointestinal histoplasmosis (GIH) is an uncommon disease with protean manifestations. It may occur as a result of mediastinal histoplasmosis or in the setting of progressive dissemination. GIH may be misdiagnosed as inflammatory bowel disease, malignancy, or other intestinal diseases leading to inappropriate therapies and unnecessary surgical interventions. Patients with bowel obstruction, perforation, or bleeding, and systemic findings suggestive of histoplasmosis should be evaluated for GIH. This is especially true for immunosuppressed patients, especially those with AIDS. Diagnosis first requires consideration of histoplasmosis in the differential in patients with the above types of gastrointestinal abnormalities, and second, familiarity with a battery of mycologic and serologic tests. Progressive disseminated histoplasmosis (PDH) is lethal if left untreated, and treatment is highly effective. This review will focus on the clinical and histopathologic features of GIH, the approach to diagnosis, and recommendations for treatment.