"Among patients with disseminated histoplasmosis, central nervous system involvement is uncommon, reported in ~5–20% of cases 2. CNS histoplasmosis may also rarely present as an isolated focal infection 3,5."
"Diagnosis "
"Pathology "
"Radiographic features "
"Treatment and prognosis "
"H. capsulatum is distributed ubiquitous globally4 and exists as an infectious, multicellular, spore-forming mould in soil that are contaminated with bird or bat droppings 6,7. Humans are exposed via spore inhalation 4."
"Central nervous system (CNS) histoplasmosis refers to CNS involvement in histoplasmosis, a pulmonary and haematogenous disease caused by the dimorphic fungus, Histoplasma capsulatum 1."
"Workup includes exposure history to H. capsulatum, imaging, detection of Histoplasma antigen and anti-Histoplasma antibodies in serum and CSF, CSF culture, detection of Histoplasma antigen in urine, and/or brain biopsy 1."
"H. capsulatum is distributed ubiquitous globally4 and exists as an infectious, multicellular, spore-forming mould in soil that are contaminated with bird or bat droppings 6,7. Humans are exposed via spore inhalation 4."
"Upon exposure to human body temperature, H. capsulatum spores alter their gene expression in a regulated sequence, enabling their transformation into a parasitic, unicellular yeast form 8. Thus, H. capsulatum is described as dimorphic, as it has temperature-regulated differentiation capabilities 8."
"These parasitic Histoplasma yeast establishes itself in macrophages, and possess numerous virulence factors to invade and evade host immunity. The yeast is ingested by alveolar macrophages via complement receptor-mediated phagocytosis. It then grows and divides within host macrophages and ultimately induces apoptosis, allowing it to infect additional cells and disseminate systemically 4. The pathogen can also form tissue granulomas to establish latency 4,7."
"CNS involvement occurs when Histoplasma yeasts are disseminated to the meninges or brain 5."
Expected headings
"Diagnosis "
"Pathology "
"Radiographic features "
"CT/MRI"
"Nuclear medicine"
"Treatment and prognosis "
"Immunocompromised patients are most commonly affected; however, ~20% of cases occur in individuals without underlying immunodeficiency 1."
"Symptoms may present in an acute, subacute or chronic pattern 1. CNS histoplasmosis may be a result of primary acute infection or from reactivation in the setting of immunosuppression 4."
"Focal ring-enhancing lesions scattered through the brain and spinal cord are a common finding for CNS histoplasmosis 1,5. Other imaging features include ventricular enlargement, meningeal enhancement, diffusion restriction, T2/FLAIR signal abnormalities 1, abscess 9, infarcts 3, hydrocephalus, meningitis and vasculitis 13."
"Focal ring-enhancing lesions scattered through the brain and spinal cord are a common finding for CNS histoplasmosis 1,5. Other imaging features include ventricular enlargement, meningeal enhancement, diffusion restriction, T2/FLAIR signal abnormalities 1, abscess 9, infarcts 3, hydrocephalus, meningitis and vasculitis 13."