Unusual cause of dementia in an immunocompetent host: toxoplasmic encephalitis

Abstract

A 69-year-old male was presented with a 2-month history of cognitive decline. The most profound deficit was observed in short-term verbal and visual memory and recognition. He was otherwise healthy, apart from atrial fibrillation diagnosed 5 months before. Brain MRI revealed T2 hyperintensities in the left thalamus, right pulvinar thalami, both putamina and right head of caudate nucleus without diffusion restriction on DWI sequences. CSF examination revealed elevated proteins. He was HIV negative. The course of the disease was complicated with gram negative sepsis and the patient died 14 days later. Autopsy revealed the brain lesions to have been caused by toxoplasmic encephalitis. Toxoplasmic encephalitis is an extremely rare cause of rapidly progressive dementia in immunocompetent patients. In patients with multiple lesions, hyperintense on T2 and hypointense on T1 weighted sequences, without diffusion restriction and some expansive effect, infectious causes should be considered, even in the absence of classical signs of infectious diseases and CSF pleocythosis.

Multiple-ring enhancing lesions in an immunocompetent adult

“…[11] At MRI, the toxoplasma lesions are multiple, commonly located in the deep central nuclei, posterior fossa or lobar at the gray-white matter junction, with prominent associated mass effect and edema and typically show intense rim enhancement after gadolinium administration. [412] As in the present case, a cerebral toxoplasma abscess may have the same appearance as a pyogenic abscess on contrast-enhanced MRI. The toxoplasma lesions are hyperintense on T2- and hypointense on T1-weighted sequences.…”

“…Human infection is usually oligosymptomatic in immunocompetent individuals and the disease is considered to be self-limited and does not require treatment. [134] Severe acute disseminated toxoplasmosis has been rarely described in immunocompetent patients and,[56] occasionally in normal patients, wherein they can develop long-lasting symptoms. [78] The most common histological finding of toxoplasma abscess is nonspecific coagulative necrosis without toxoplasmic cysts.…”

Toxoplasmosis and Polygenic Disease Susceptibility Genes: ExtensiveToxoplasma gondiiHost/Pathogen Interactome Enrichment in Nine Psychiatric or Neurological Disorders

“…Any link between Alzheimer's disease and toxoplasmosis is limited to a seroprevalence study [13] and to scattered case reports [164, 165]. …”

Hemophagocytic Syndrome as Uncommon Presentation of Disseminated Toxoplasmosis in an Immunocompetent Adult from Chinese Kunming

“…The organs most often involved are the lungs, heart, and brain, but any organ or system can eventually be involved. [9][10][11][12] In this case, our patient developed an atypical pneumonia, with cavities and pleural effusion. Biological findings revealed elevated concentrations of liver enzymes, glucose, and direct bilirubin, suggesting the patient had developed hepatitis.…”