# Anti-AMPA-Receptor Encephalitis Presenting as a Rapid-Cycling Bipolar Disorder in a Young Woman with Turner Syndrome

## TL;DR

A young woman with Turner syndrome showed symptoms of bipolar disorder but was later diagnosed with an autoimmune brain condition and improved with treatment.

## Contribution

Highlights a rare case linking anti-AMPA-receptor encephalitis with psychiatric symptoms in a patient with Turner syndrome.

## Key findings

- The patient showed marked improvement after treatment with memantine and valproic acid.
- Autoimmune encephalitis was diagnosed despite initial presentation as treatment-resistant bipolar disorder.
- Turner syndrome may be a risk factor for autoimmune conditions like encephalitis.

## Abstract

Background. Autoimmune encephalitis is a disorder characterised by the subacute onset of seizures, short-term memory loss, and psychiatric and behavioural symptoms. Initially, it was recognised as a paraneoplastic disorder, but recently a subgroup of patients without systemic cancer was identified. Case Description. We describe a 20-year-old woman with Turner syndrome presenting with a treatment-resistant rapid cycling bipolar disorder with cognitive impairment. She was diagnosed with anti-AMPA-receptor encephalitis. She showed marked improvement after starting memantine and valproic acid. Conclusion. This case description emphasises the importance of timely recognition of autoimmune limbic encephalitis in patients with psychiatric manifestations and a possible predisposition to autoimmune conditions, in order to rule out malignancy and to quickly initiate treatment.