Nystagmus and Imbalance as the Presenting Symptoms of Anti Gad Antibody Syndrome in A 67-Year-Old Female

Abstract

Autoimmune encephalitis is a serious condition that causes brain inflammation, usually mediated by antibodies to various neuronal antigens [1]. One of the many antigens that may generate an immune response and cause this type of inflammation is the glutamic acid decarboxylase enzyme (GAD). AntiGAD (glutamic acid decarboxylase) antibodies are targeted against the GAD enzyme that converts glutamate to GABA, which is the nervous system’s primary inhibitory neurotransmitter [2]. With the body’s primary inhibitory neurotransmitter compromised, anti-GAD antibody syndrome is a rare type of autoimmune encephalitis that results in various symptoms related to prolonged excitation, such as seizures or nystagmus [3]. We present a rare case of autoimmune encephalitis caused by significantly elevated Anti-GAD antibody, with concomitant rheumatoid arthritis in the hands/wrists; symptoms of downbeat nystagmus, diplopia, headaches, and joint pain are improved with rituximab and IVIG infusion, following an unsuccessful treatment with oral prednisone.