A 16-year-old girl in California walked into an ER hallucinating a \u201cflying green dinosaur\u201d and hearing voices \u2014 and it turned out her immune system was attacking her own brain wiring.<\/p>\n
Live Science\u2019s Diagnostic Dilemma (Oct. 14) walks through the case report: trembling, sweating, racing pulse, shallow breathing. She\u2019d described hallucinations since seventh grade; her parents said the psychosis spiked only 48 hours before arrival. CT scan: clean. First spinal tap: failed. EEG: no answers. Day two: full catatonia. Lorazepam brought her back. Psych transfer stalled when she couldn\u2019t feed herself.<\/p>\n
The breakthrough came later: cerebrospinal fluid tested positive for autoantibodies targeting neuronal intermediate filament (NIF) \u2014 structural proteins in nerve cells. Diagnosis: autoimmune encephalitis. No tumor on MRI or PET. Treatment stacked steroids, immunoglobulin, rituximab, and five rounds of plasmapheresis. Nearly two months in hospital, then a year of tapering psych meds while immunotherapy continued.<\/p>\n
Autoimmune encephalitis is rare \u2014 roughly 5 to 8 per 100,000 in one U.K. study \u2014 and pediatric anti-NIF cases are rarer still than the better-known anti-NMDA flavor. The girl\u2019s family noted a cough three weeks earlier after a Philippines trip. The \u201cdinosaur\u201d wasn\u2019t a punchline. It was a medical alarm bell with feathers of green.<\/p>\n