A Case Report of Acute Intermittent Porphyria Mimicking Autoimmune Encephalitis.

A 21-year-old female patient had recurrent visits to the ED with chest pain managed conservatively, then developed recurrent episodes of seizures and became encephalopathic. She eventually landed in the intensive care unit with extensive investigations to confirm or rule out infective and noninfective etiologies for encephalitis. Her cerebrospinal fluid examination was unremarkable, including autoimmune encephalitis screening. The MRI brain had juxtacortical and in places cortical signal change, with a possibility of an encephalitic process going on. Furthermore, influenza type B was detected on blood screening, and the EEG showed generalized slow-wave discharges. She had dilated pupils, raised blood pressure, and low sodium levels, which pointed toward autonomic instability. Keeping in view autonomic instability, new onset seizures, preceded chest pain, and encephalopathic EEG, she was screened for porphyria and diagnosed with the condition.