NA

Anti-GAD 65 antibody syndromes have a wide array of presentations, including Stiff Person Syndrome, cerebellar ataxia, autoimmune epilepsy, and associated functional components, to name a few. Given the varied and overlapping presentations, diagnostic dilemmas have arisen. Similarly, the response to treatment has been variable.

NA

A 79-year-old female with a past medical history of hypertension presented with hyperglycemia, sudden choreo-dystonic movements characterized by stereotyped hyperkinetic movements, irritability, gait imbalance with recurrent falls, dysarthria, and dysphagia on examination. The patient had no neurological family history. The admission blood workup showed a 993 mg/dl glucose level, and the hemoglobin A1C was>14%. Routine CSF analysis reported increased glucose and protein. The serum autoimmune panel was positive for anti-GAD 65 302.6 U/ml, thyroid peroxidase, thyroglobulin, and anti-cardiolipin IgG antibodies. EEG showed diffuse brain dysfunction and epileptogenic potentials. Huntington's gene testing was negative. MRI of the brain showed involutional changes and leukoencephalomalacia. Infection and malignancy were ruled out. The patient was treated with five courses of IVIG without clinical improvement, in addition to Levetiracetam, for seizure management. Later, high-dose IV methylprednisolone resulted in a remarkable improvement in her symptoms. At one-month follow-up, the patient reported improvement in irritability, gait, balance, dysphagia, and dysarthria. She received long-term glucose control and physical therapy. 

Anti-GAD 65 encephalitis requires a high index of suspicion for underlying autoimmune disease and early diagnosis to initiate therapy promptly to achieve better outcomes to avoid severe neurological impairment, coma, and death.  Therapeutic approaches include two strategies: symptomatic or immunologic. Symptomatic treatment, such as antispasmodics, has shown better results, followed by immunotherapy and immunosuppressants. While corticosteroids have been reported to be ineffective, this patient's condition improved dramatically with steroids and not IVIG. Treatment, therefore, should be patient-specific.