Voltage-gated potassium channel antibody limbic encephalitis: a case illustrating the neuropsychiatric and PET/CT features with clinical and imaging follow-up.

Objective: To illustrate the neuropsychiatric and imaging findings in a confirmed case of voltage-gated potassium channel antibody limbic encephalitis.

Method: Case report and review of the literature.

Results: A 64-year-old man presented with several months' history of obsessive thoughts and compulsions associated with faciobrachial dystonic seizures. He had no significant past medical and psychiatric history. Physical examinations revealed only mildly increased tone in the left upper limb. Bedside cognitive testing was normal. Positron-emission tomography showed intense symmetrical uptake in the corpus striatum. No underlying malignancy was identified on whole body imaging. Magnetic resonance imaging, lumbar puncture and electroencephalogram were normal. Serum voltage-gated potassium channel antibodies were strongly positive. The patient had a favourable response to antiepileptic drugs, oral steroids and immunotherapy.

Conclusions: Voltage-gated potassium channel limbic encephalitis characteristically presents with neuropsychiatric symptoms and temporal lobe seizures. Positron-emission tomography-computed tomography can be a useful adjunct to the clinical and biochemical work-up.