Guest posting: Dr Thérèse Boyle, Immunology Advanced Trainee Registrar, Health Pathology NSW.
Take home messages-
- Autoimmune encephalitis is divided into 2 main categories; classic onco-neuronal encephalitis that is generally paraneoplastic, and limbic encephalitis of which anti-NMDA receptor encephalitis is one of the most common forms.
- Autoantibodies within these categories can causes syndromes other than encephalitis.
- NMDA receptor encephalitis has a multiphasic presentation, usually with a prodrome, psychiatric followed by neurological symptoms and subsequent slow resolution (with treatment).
- Up to 50% females and <5% males with anti-NMDA receptor encephalitis have an underlying malignancy (ovarian teratomas being most common).
- EBV and Mycoplasma infections have also been associated with development of these antibodies.
- Anti-NMDA receptor antibody detection is most sensitive and specific in CSF (~30% cases missed, and antibodies detectable in other conditions in serum).
- Early recognition and treatment with immunosuppression (and surgery when appropriate) leads to better outcomes.
- ~80% of patients with anti-NMDAR encephalitis recover within 2 years, leaving ~20% with persistent morbidity or mortality. This severe form of encephalitis is a particularly important area of ongoing research.