Autoimmune encephalitis mimicking sporadic Creutzfeldt-Jakob disease: A retrospective study

- We present clinical, imaging findings of autoimmune encephalopathies (AE) and sporadic Creutzfeldt-Jakob disease (CJD).
- We compare clinical presentation, signs and outcome of patients with AE and sCJD patients.
- We emphasize the importance of early diagnosis and treatment on outcome.
- Correct discrimination between myoclonus-like movements and myoclonus is paramount for early identification.

Autoimmune encephalitis associated with anti-voltage-gated potassium channel antibodies are most likely to be misdiagnosed as sporadic Creutzfeldt-Jakob disease (sCJD). Our goal was to delineate patients who were initially suspected to have CJD but were later found to have AE. We performed a retrospective clinical review of cases of individuals and made a comparison between groups of patients diagnosed with sCJD and AE. Patients who had rapidly progressing dementia and focal neurological impairment, such as aphasia, gait disturbance, visual disturbance, and depression, at onset were diagnosed with sCJD, whereas epilepsy, hyponatremia and dysautonomia were strong hints for AE. Fluoroscope-positron emission tomography (PET) of patients with AE revealed variable metabolism and normative and long-term immunosuppression were less likely to relapse.

The mode of grey matter involvement was different between the sCJD and AE patients. In group of AE, 5 of 8 patients only had grey matter hyperintensities in limbic area but no patients in group of sCJD merely had hyperintensity solely lin limbic cortex. Only one patients with AE had hyperintensities in the neocortical, limbic and subcortical grey matter.64