Autoimmune encephalitis (AE) is a form of non-infectious neuroinflammation that has become an increasingly recognized cause of acute/subacute progressive mental status change with a variety of clinical phenotypes.

It is an important differential diagnosis in young people or adults presenting with an acute onset of new neurological or psychiatric symptoms without a past context of mental health problems.

Subtypes:

• definite limbic encephalitis
• acute disseminated encephalomyelitis
• anti-NMDA receptor encephalitis
• Hashimoto's encephalopathy

PC

• Autoimmune encephalitis can present with a wide range of symptoms, including confusion, seizures, movement disorders, behavioural changes, emotional lability, psychosis, cognitive impairment and reduced conscious level.
• The onset in young people is often faster than in adults.
• Symptoms may fluctuate but usually progress over days to weeks.

Differentials

• SOL
• meningoencephalitis
• stroke
• trauma
• non-convulsive status epilepticus
• acute demyelinating encephalomyelitis