[African histoplamosis. A report of three pediatric cases]

Epidemiological, clinical, diagnostic, and therapeutic features of histoplasmosis: A systematic review

Histoplasmosis is a mycosis due to a dimorphic fungus Histoplasma capsulatum. This study aimed at providing an overview of histoplasmosis epidemiological, clinical, diagnostic, and therapeutic aspects from the last 30 years. This review was carried out using a systematic literature search on histoplasmosis from 1992 to 2021. We describe the clinical features, diagnostic methods and treatment. Empirical searches were conducted via the databases PubMed, Google Scholar and Science Direct. Between 1992 and 2021, 190 manuscripts were published and reported 212 cases of histoplasmosis. These publications included 115 and 97 cases of American and African histoplasmosis respectively. The number of publications increased over the last ten years with a maximum in 2020 (12.34 % of the cases reported). The disseminated forms of histoplasmosis were the most frequently reported cases as compared to the localized forms. This was the case with the American histoplasmosis (75.65 %) as well as with the African histoplasmosis (55.67 %). Itraconazole (31.17 %) and Amphotericin B (26.62 %) were the most used drugs in the management of these cases. American histoplasmosis is distributed worldwide whereas African histoplasmosis is mainly present in intertropical Africa. There is a critical need for setting up a global surveillance system, towards a better understanding of the disease.

Osteoarticular Mycoses

Osteoarticular mycoses are chronic debilitating infections that require extended courses of antifungal therapy and may warrant expert surgical intervention. As there has been no comprehensive review of these diseases, the International Consortium for Osteoarticular Mycoses prepared a definitive treatise for this important class of infections. Among the etiologies of osteoarticular mycoses are Candida spp., Aspergillus spp., Mucorales, dematiaceous fungi, non-Aspergillus hyaline molds, and endemic mycoses, including those caused by Histoplasma capsulatum, Blastomyces dermatitidis, and Coccidioides species. This review analyzes the history, epidemiology, pathogenesis, clinical manifestations, diagnostic approaches, inflammatory biomarkers, diagnostic imaging modalities, treatments, and outcomes of osteomyelitis and septic arthritis caused by these organisms. Candida osteomyelitis and Candida arthritis are associated with greater events of hematogenous dissemination than those of most other osteoarticular mycoses. Traumatic inoculation is more commonly associated with osteoarticular mycoses caused by Aspergillus and non-Aspergillus molds. Synovial fluid cultures are highly sensitive in the detection of Candida and Aspergillus arthritis. Relapsed infection, particularly in Candida arthritis, may develop in relation to an inadequate duration of therapy. Overall mortality reflects survival from disseminated infection and underlying host factors.

Histoplasmosis in African children: clinical features, diagnosis and treatment

Most of the reviews on histoplasmosis documented in literature have been in the adult population. Very few studies highlight the peculiarities associated with histoplasmosis in Africa especially in the pediatric population. This review addresses the above concerns with clinical summaries and diagnosis of some case reports of histoplasmosis in African children. We highlighted 44 case reports of histoplasmosis in African children (1950–2021) distributed across Western Africa (38.6%, n = 17), Eastern Africa (9.1%, n = 4), Southern Africa (9.1%, n = 4), and Central Africa (43.2%, n = 19). No case report was found from Northern Africa. The age range was 1–17 years, with a mean of 9.2. Of the 44 case reports, 8 cases (18.2%, 8/44) were caused by Histoplasma capsulatum var capsulatum, 33 cases (75%, 33/44) were caused by Histoplasma capsulatum var duboisii, and specie identification was not found in 3 cases. Only three (6.8%) cases were HIV positive; 56.8% (25/44) were disseminated histoplasmosis, pulmonary histoplasmosis accounted for just one case (2.3%, 1/44). Extrapulmonary presentation included skin lesions (ulcers, fistulas, nodules, patches, pigmentations, papules, and abscesses), bone lesions, osteoarthritis, and fractures. The commonest sites affected were skin ( n = 29, 65.9%), bones ( n = 20, 45.5%), and lymph nodes ( n = 15, 34.1%). Histopathology was the commonest diagnostic method ( n = 33, 75%). Amphotericin B was first-line therapy in 45.5% of the cases ( n = 20) followed by ketoconazole (20.5%, n = 9); 27 cases (61.4%) had favorable outcomes, 8 cases (18.2%) had fatal outcomes, while in 9 cases, the outcome was not revealed. This review revealed several cases of histoplasmosis misdiagnosed as other conditions including tuberculosis ( n = 3, 6.8%), pneumonia ( n = 1, 2.3%), cancers ( n = 4, 9.1%), nephritic syndrome ( n = 1, 2.3%), leishmaniasis ( n = 1, 2.3%), and hyperreactive malarial splenomegaly syndrome ( n = 1, 2.3%). In addition, histoplasmosis was not considered in some case reports even when symptoms were suggestive. Diagnosis of histoplasmosis was made at autopsy with postmortem findings suggestive of histoplasmosis ( n = 3, 6.8%). This report highlights the need for a paradigm shift on the part of pediatricians in Africa. They need to look beyond clinical conditions considered common in our environment for this age group and evaluate for other diseases including histoplasmosis.

Histoplasmosis Caused by Histoplasma capsulatum var. duboisii: A Comprehensive Review of Cases From 1993 to 2019

BACKGROUND

Histoplasmosis caused by Histoplasma capsulatum var. duboisii (Hcd) is a rare, but probably underestimated, endemic infection described in intertropical Africa. Therefore, the epidemiology of the infection remains unclear, and there is no consensus on therapeutic management.

METHODS

Using a comprehensive search on different Internet databases, we collected case reports of Hcd infection published from 1993 to 2019. Epidemiological and clinical charts and therapeutic strategies were analyzed.

RESULTS

We found 94 well-documented cases of Hcd infection, and 30.1% of the patients were under 18 years old. Symptoms occurred in some patients several decades after leaving the endemic area. Cutaneous/subcutaneous lesions, bone infections, and lymphadenopathies, both isolated and combined, were the most frequent presentations. The human immunodeficiency virus (HIV) coinfection rate was at 20.8%, with fever, lymphadenopathies, and an absence of bone infection being the differentiating elements from patients living without HIV. The rate of disseminated forms (60.6% in our review) significantly increased as compared to studies published before 1993, but without correlation with HIV infection. The global mortality rate was at 23.4% by the end of follow-up. The outcome was not correlated with the antifungal drug prescribed, nor with HIV serologic status, but was correlated with the initiation of an antifungal therapy.

CONCLUSIONS

Hcd histoplasmosis is a severe fungal infection for which the precise mode of acquisition remains to be determined. There is a need for affordable and more specific diagnostic tools. Itraconazole and amphotericin B are the best therapeutic alternatives and should be available in all low-income countries of the endemic area.

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.

Histoplasmosis in the Republic of Congo dominated by African histoplasmosis, Histoplasma capsulatum var. duboisii

The Republic of Congo (RoC) is one of the African countries with the most histoplasmosis cases reported. This review summarizes the current status regarding epidemiology, diagnostic tools, and treatment of histoplasmosis in the RoC. A computerized search was performed from online databases Medline, PubMed, HINARI, and Google Scholar to collect literature on histoplasmosis in the RoC. We found 57 cases of histoplasmosis diagnosed between 1954 and 2019, corresponding to an incidence rate of 1-3 cases each year without significant impact of the AIDS epidemic in the country. Of the 57 cases, 54 (94.7%) were cases of Histoplasma capsulatum var. duboisii (Hcd) infection, African histoplasmosis. Three cases (5.3%) of Histoplasma capsulatum var. capsulatum infection were recorded, but all were acquired outside in the RoC. The patients' ages ranged between 13 months to 60 years. An equal number of cases were observed in adults in the third or fourth decades (n = 14; 24.6%) and in children aged ≤15 years. Skin lesions (46.3%), lymph nodes (37%), and bone lesions (26%) were the most frequent clinical presentations. Most diagnoses were based on histopathology and distinctive large yeast forms seen in tissue. Amphotericin B (AmB) was first line therapy in 65% of the cases and itraconazole (25%) for maintenance therapy. The occurrence of African histoplasmosis in apparently normal children raises the possibility that African histoplasmosis is linked to environmental fungal exposure.

A Case of Histoplasma duboisii Brain Abscess and Review of the Literature

Histoplasmosis is a fungal disease caused by Histoplasma capsulatum var. capsulatum (Hcc) and H. capsulatum var. duboisii (Hcd). Central nervous system (CNS) involvement is rare. So far, the few cases reported having Histoplasmosis associated brain abscesses were caused by H. capsulatum var. capsulatum. Herein, we report a unique case of brain abscess caused by H. capsulatum var. duboisii occurring in a 42-year-old immunocompromised woman with HIV. Initially, she presented with hypothermia, vomiting, frontal headache, evolving over one month. She then progressed to have a generalized seizure. Brain MRI showed multifocal brain abscesses and a frontal osteitis. The frontal osteitis was biopsied and confirmed the diagnosis of H. capsulatum var. duboisii. She was successfully treated with liposomal amphotericin B (150 mg daily) for the first four weeks and itraconazole (200mg twice daily) for six months.

African histoplasmosis in a Guinea Bissau patient with HIV-2: Case report and review

African histoplasmosis is the relatively unknown infection by Histoplasma capsulatum var. duboisii. It is endemic to Central and West Africa, generally involving the skin with potential for systemic dissemination, and has been described mainly in immunocompetent hosts. We present the case of a 30-year-old Bissau-Guinean man with HIV-2 infection known for 16 years, irregularly treated, admitted with two weeks of fever, diarrhoea and cutaneous lesions. Examination revealed multiple subcutaneous nodes, Molluscum contagiosum-like lesions, generalized lymphadenopathy and painful palpation of the left iliac fossa. Laboratory tests showed severe nonhaemolytic anaemia and CD4+ count of 9/mm3, with normal creatinine and hepatic enzymes. Chest roentgenogram was unremarkable and a research for Mycobacterium tuberculosis by GeneXpert® was negative. Nonetheless, given the lack of further diagnostic tools, a presumptive diagnosis of disseminated tuberculosis was made, and the patient was started on tuberculostatic and antiretroviral drugs. Despite initial improvement, a national shortage of antiretrovirals precluded further treatment, with worsening of the clinical picture, namely an increase in the number and dimensions of the skin lesions. An excisional biopsy of a subcutaneous nodule revealed Histoplasma capsulatum var. duboisii. Unfortunately, due to the unavailability of antifungals, the patient died one week later. To our best knowledge, this is the first confirmed case of an HIV infected patient with African histoplasmosis in Guinea-Bissau.