Disseminated histoplasmosis in pediatric kidney transplant recipients-A report of six cases and review of the literature

Endemic mycoses in children in North America: a review of radiologic findings

Clinically significant endemic mycoses (fungal infections) in the United States (U.S.) include Blastomyces dermatitidis, Histoplasma capsulatum, and Coccidioides immitis/posadasii. While the majority of infections go clinically unnoticed, symptomatic disease can occur in immunocompromised or hospitalized patients, and occasionally in immune-competent individuals. Clinical manifestations vary widely and their diagnosis may require fungal culture, making the rapid diagnosis a challenge. Imaging can be helpful in making a clinical diagnosis prior to laboratory confirmation, as well as assist in characterizing disease extent and severity. In this review, we discuss the three major endemic fungal infections that occur in the U.S., including mycology, epidemiology, clinical presentations, and typical imaging features with an emphasis on the pediatric population.

Case report: Disseminated histoplasmosis in a renal transplant recipient from a non-endemic region

Histoplasmosis is the most common endemic fungal infection in the USA. The majority of cases are asymptomatic and have clear exposure to endemic regions. In contrast, we present an adolescent immunocompromised patient with systemic and relatively non-specific symptoms including abdominal pain, weight loss, lower extremity edema, and scabbing skin lesions, without known exposure to endemic areas for histoplasmosis. Histologic analysis of gastrointestinal and skin biopsies eventually revealed a diagnosis of disseminated histoplasmosis; the patient was successfully treated with amphotericin B followed by itraconazole maintenance therapy. Ultimately, a high bar of suspicion for fungal disease must be maintained in immunosuppressed individuals even without apparent exposure history to endemic areas. This case report serves as a valuable reference for practitioners evaluating differential diagnosis of infections in immunocompromised patients.

Case report: Histoplasmosis presenting as asymptomatic hypercalcemia detected on routine laboratory testing in a pediatric kidney transplant recipient

Among all infections occurring in pediatric kidney transplant recipients, approximately 1%-5% are fungal. Most fungal infections occur in the first 6 months following kidney transplantation. We present the case of a 15-year-old boy with a history of a kidney transplant 4 years ago, who was found to have asymptomatic moderate hypercalcemia on routine laboratory testing, along with an acute deterioration of his kidney function markers. The cause of his acute kidney injury was likely related to hypercalcemia. An extensive workup for hypercalcemia revealed infection with Histoplasma capsulatum (histoplasmosis) with multiple pulmonary nodules. Hypercalcemia that was initially refractory to medical management resolved after initiating the antifungal treatment. Fungal granulomatous infections such as histoplasmosis should be considered in the differential diagnosis of hypercalcemia in an asymptomatic pediatric kidney transplant recipient.

Histoplasmosis in Children; HIV/AIDS Not a Major Driver

The classification of histoplasmosis as an AIDS-defining illness has largely attributed its occurrence in people to the presence of HIV/AIDS especially in Africa. Prior to the advent of the HIV/AIDS epidemic, several cases of histoplasmosis were documented both in the pediatric and adult populations. Our review revealed 1461 reported cases of pediatric histoplasmosis globally in the last eight decades (1939-2021). North America (n = 1231) had the highest number of cases, followed by South America (n = 135), Africa (n = 65), Asia (n = 26) and Europe (n = 4). Histoplasmosis was much more common in the non-HIV pediatric population (n = 1418, 97.1%) compared to the HIV population. The non-HIV factors implicated were, childhood malignancies (n = 207), such as leukemias and lymphomas as well as their treatment, lung diseases (n = 7), environmental exposures and toxins (n = 224), autoimmune diseases (n = 12), organ transplants (n = 12), long-term steroid therapy (n = 3), the use of immunosuppressive drugs such as TNF-alpha inhibitors (n = 7) malnutrition (n = 12), histiocytosis (n = 3), Hyper immunoglobulin M and E syndromes (n = 15, 1.2%), pancytopenia (n = 26), diabetes mellitus (n = 1) and T-cell deficiency (n = 21). Paediatricians should always consider or rule out a diagnosis of histoplasmosis in children presenting with symptoms suggestive of the above clinical conditions.

Paediatric Histoplasmosis 2000-2019: A Review of 83 Cases

Histoplasmosis is an endemic fungal infection that is confined to specific geographical regions. Histoplasma spp. are primary pathogens that cause disease in both immunocompetent and immunocompromised patients, ranging from a single-organ (mostly affecting the lungs) infection to life-threatening disseminated disease. Knowledge about the clinical epidemiology relies on data from adult populations; little is known about the patient and disease characteristics in the paediatric population. Therefore, a structured review of published cases of paediatric histoplasmosis between 2000 and 2019 was performed. A literature search of PubMed was conducted and the epidemiological and clinical data from 83 cases were analysed. The mean age at presentation was 9.5 ± 5.5 years, and 51% were girls. Two-thirds of the children were immunocompromised. The majority of children presented with disseminated disease. The most frequently observed clinical symptoms were respiratory symptoms, alongside non-specific systemic features, including fever, myalgia, fatigue and weight loss. The mortality rate was 11%. Histoplasmosis affects children of any age. Being immunocompromised is a risk factor for severe and disseminated disease. The lack of specific presenting features leads to underreporting and delay in diagnosis. To improve the recognition and outcome of histoplasmosis in childhood, increased awareness and surveillance systems are warranted.

Treating progressive disseminated histoplasmosis in people living with HIV

BACKGROUND

Progressive disseminated histoplasmosis (PDH) is a serious fungal infection that affects people living with HIV. The best way to treat the condition is unclear.

OBJECTIVES

We assessed evidence in three areas of equipoise. 1. Induction. To compare efficacy and safety of initial therapy with liposomal amphotericin B versus initial therapy with alternative antifungals. 2. Maintenance. To compare efficacy and safety of maintenance therapy with 12 months of oral antifungal treatment with shorter durations of maintenance therapy. 3. Antiretroviral therapy (ART). To compare the outcomes of early initiation versus delayed initiation of ART.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register; Cochrane CENTRAL; MEDLINE (PubMed); Embase (Ovid); Science Citation Index Expanded, Conference Proceedings Citation Index-Science, and BIOSIS Previews (all three in the Web of Science); the WHO International Clinical Trials Registry Platform, ClinicalTrials.gov, and the ISRCTN registry, all up to 20 March 2020.

SELECTION CRITERIA

We evaluated studies assessing the use of liposomal amphotericin B and alternative antifungals for induction therapy; studies assessing the duration of antifungals for maintenance therapy; and studies assessing the timing of ART. We included randomized controlled trials (RCT), single-arm trials, prospective cohort studies, and single-arm cohort studies.

DATA COLLECTION AND ANALYSIS

Two review authors assessed eligibility and risk of bias, extracted data, and assessed certainty of evidence. We used the Cochrane 'Risk of bias' tool to assess risk of bias in randomized studies, and ROBINS-I tool to assess risk of bias in non-randomized studies. We summarized dichotomous outcomes using risk ratios (RRs), with 95% confidence intervals (CI).

MAIN RESULTS

We identified 17 individual studies. We judged eight studies to be at critical risk of bias, and removed these from the analysis. 1. Induction We found one RCT which compared liposomal amphotericin B to deoxycholate amphotericin B. Compared to deoxycholate amphotericin B, liposomal amphotericin B may have higher clinical success rates (RR 1.46, 95% CI 1.01 to 2.11; 1 study, 80 participants; low-certainty evidence). Compared to deoxycholate amphotericin B, liposomal amphotericin B has lower rates of nephrotoxicity (RR 0.25, 95% CI 0.09 to 0.67; 1 study, 77 participants; high-certainty evidence). We found very low-certainty evidence to inform comparisons between amphotericin B formulations and azoles for induction therapy. 2. Maintenance We found no eligible study that compared less than 12 months of oral antifungal treatment to 12 months or greater for maintenance therapy. For both induction and maintenance, fluconazole performed poorly in comparison to other azoles. 3. ART We found one study, in which one out of seven participants in the 'early' arm and none of the three participants in the 'late' arm died.

AUTHORS' CONCLUSIONS

Liposomal amphotericin B appears to be a better choice compared to deoxycholate amphotericin B for treating PDH in people with HIV; and fluconazole performed poorly compared to other azoles. Other treatment choices for induction, maintenance, and when to start ART have no evidence, or very low certainty evidence. PDH needs prospective comparative trials to help inform clinical decisions.