Steroid unresponsive anti-NMDA receptor encephalitis during pregnancy successfully treated with plasmapheresis

Anti-N-methyl-d-aspartate (NMDA) receptor encephalitis is an autoimmune disorder resulting in neurological and psychiatric symptoms. It is rare during pregnancy and treatment is extremely challenging as little data exist to guide management. A 26-year-old woman presented at 22 weeks of gestation with intermittent headache and an acute episode of bizarre behaviour and grandiose delusions resulting in hospitalisation. The patient was worked up for encephalitis and was found to have anti-NMDA receptor antibody in cerebrospinal fluid as well as in serum. She was initially treated with high-dose steroids but failed to improve clinically and serologically. She was then treated with plasmapheresis and showed clinical and serological response. She had a successful delivery at 37 weeks and the baby did not show serological evidence of disease. This case adds to the sparse literature of anti-NMDA receptor encephalitis during pregnancy and adds to the differential diagnosis of new onset psychiatric symptoms during pregnancy.