Anti glutamic acid decarboxylase antibody mediated encephalopathy while on etanercept in a patient with multiple autoimmune diseases

A 39 year old lady presented with an altered mental state and unsteadiness of gait. She had a history of juvenile idiopathic arthritis, autoimmune thyroiditis and alopecia, protein S deficiency with vena cava thrombosis, previous excision of ovarian mass and vasculitic rash. There was a previous history of ovarian mass and her immunomodulatory therapy for arthritis over the previous year was Etanercept. She used recreational cannabis but denied any other illicit drug usage. Her affect was variable and at times inappropriate with frequent laughter. She would spit regularly. There was anxiety and a prevailing sensation of doom. There was no clinical evidence of seizure activity. There were mild cerebellar signs with ataxia and gaze evoked nystagmus. Initial Addenbrooke's cognitive examination (ACE) revealed deficits predominantly in memory, fluency and language with an overall score of 47/100. Urine toxicology detected cannabis and nothing else. MRI demonstrated T2 hyperintensities in the cerebellum and left inferior cerebellar peduncle. CSF analysis revealed an elevated white cell count of 60 (90% lymphocytes, 10% polymorphs) and protein of 802mg/L. She was initially treated with acyclovir for presumed viral encephalitis although PCR was negative for HSV, varicella, enterovirus, JC virus and BK virus. EEG was unremarkable. Anti Glutamic Acid Decarboxylase (GAD) antibody was strongly positive at 13235 U/mL. Other antibodies including anti–NMDA, anti–voltage gated po...
Source: Journal of Neurology, Neurosurgery and Psychiatry - Category: Neurosurgery Authors: Tags: Immunology (including allergy), Brain stem / cerebellum, Drugs: CNS (not psychiatric), Epilepsy and seizures, Infection (neurology), Stroke, Drugs misuse (including addiction), Connective tissue disease, Musculoskeletal syndromes Association of British Source Type: research