The limbic system is primarily responsible for modulating behaviour, emotions and neuro-endocrine functions. Limbic encephalopathy involves this part of the brain and is characterised by the acute or sub-acute onset of seizures, recent memory loss, confusion and psychiatric symptoms. Here we describe an unusual presentation of a well-functioning elderly man, who presented with sudden onset of confusion, cognitive impairment, treatment resistant hyponatremia, seizures and psychiatric symptoms.

This 79 year old gentleman, previously well and independent was admitted to the acute hospital with a 3 week history of sudden onset of confusion, odd behaviour and weight loss. On admission he was hyponatremic (Na-118), developed treatment resistant seizures and progressive cognitive impairment. He was referred to the Liaison Psychiatry team with increasing paranoia, agitation and persecutory delusions.

MRI and CT brain remained normal. Lumbar puncture revealed a positive VGKC antibody and his blood titres for VGKC was more than 3000. His hyponatremia and seizures remained chronic, but improved with plasmapheresis, oral corticosteroids and cyclophosphamide. He was commenced on aripiprazole for psychiatric symptoms, but was transferred to the acute psychiatric unit after being detained under section 2 of the MHA due to risks of aggression and absconsion.

Psychiatric symptoms related to this form of encephalitis have not been emphasised in literature. His aggression improved over time on aripiprazole, but was transferred to a residential care home setting due to persisting cognitive deficits and social care needs This case highlights the importance of recognising multimorbidity, joint working and more research required in the area.

The authors have not supplied their declaration of competing interest.