Disseminated Histoplasmosis Infection Diagnosed by Metagenomic Next-Generation Sequencing: A Case Report

Histoplasmosis is an endemic disease caused by Histoplasma capsulatum. This systemic disease can affect various organs beyond the lungs, such as the liver, spleen, adrenal gland, and lymph nodes. The clinical symptoms can range from asymptomatic to severe, life-threatening conditions, depending on the state of the patient's immune system. This report describes a 40-year-old male who presented with reports of weight loss, low back pain, and progressively worsening movement disorder of the bilateral lower extremities for months. Computed tomography (CT) examination showed multiple lytic lesions of vertebral bodies, bilateral ribs, and pelvic bone, histopathological examination and tumor-related serum markers exclude tumors. mNGS was employed to identify H. capsulatum var. capsulatum as the etiological agent of the lesions in the bone biopsy. Through phylogenetic tree analysis, Histoplasma capsulatum var. Capsulatum (Hcc) was the main responsible pathogen, rarely reported in bone lesions. The patient underwent spinal surgery and was successfully treated with liposomal amphotericin B and itraconazole. Based on the diagnosis and treatment of this case, we discuss the epidemiologic status, clinical presentations, diagnostic criteria, and treatment guidelines of histoplasmosis to provide additional information about this disease. mNGS is utilized in this case, and it appears to be a reliable method for early and accurate diagnosis of this disease.

Disseminated histoplasmosis diagnosed in the bone marrow of an HIV-infected patient: First case imported in Tunisia

Histoplasmosis is a fungal infection caused by a dimorphic fungus, Histoplasma capsulatum. We report a first case of disseminated histoplasmosis in a 34-year-old woman, infected with human immunodeficiency virus (HIV), originating from Ivory Coast and living in Tunisia for 4 years. She was complaining from fever, chronic diarrhoea and pancytopenia. The Histoplasma capsulatum var. capsulatum was identified by direct microscopic examination of the bone marrow. She was treated by Amphotericin B, relayed by itraconazole. Even though a regression of symptoms and normalization of blood cell count (BCC), the patient died in a respiratory distress related to CMV hypoxemic pneumonia.

Amplification of blood smear DNA to confirm disseminated histoplasmosis

BACKGROUND

The prevalence of the Histoplasma capsulatum var. capsulatum (Hcc) histoplasmosis may be underestimated West Africa, both because the diagnosis is not mentioned in the early stages of the disease and due to limited biological resources available.

CASE REPORT

We report a case of disseminated histoplasmosis due to Hcc in a Senegalese HIV patient. The diagnosis was suspected following the demonstration of small encapsulated yeasts within neutrophils on a thin blood smear. It was further confirmed using a specific real-time PCR applied on a DNA specimen extracted from the thin blood smear.

CONCLUSION

To the best of our knowledge, this is the first case of Hcc infection diagnosed in Senegal. Blood smear may be a valuable screening tool in the case of bloodstream dissemination and can be used for further molecular approaches to confirm the diagnosis.

Histoplasmosis infections worldwide: thinking outside of the Ohio River valley

In the United States, histoplasmosis is generally thought to occur mainly in the Ohio and Mississippi River Valleys, and the classic map of histoplasmosis distribution reflecting this is second nature to many U.S. physicians. With the advent of the HIV pandemic reports of patients with progressive disseminated histoplasmosis and AIDS came from regions of known endemicity, as well as from regions not thought to be endemic for histoplasmosis throughout the world. In addition, our expanding armamentarium of immunosuppressive medications and biologics has increased the diagnosis of histoplasmosis worldwide. While our knowledge of areas in which histoplasmosis is endemic has improved, it is still incomplete. Our contention is that physicians should consider histoplasmosis with the right constellations of symptoms in any febrile patient with immune suppression, regardless of geographic location or travel history.