Clinical and neuropsychological course of young adult patient with anti-GAD-65 autoimmune encephalitis: A case report.

Objective

Among autoimmune limbic encephalitis syndromes, glutamic acid decarboxylase 65 (GAD65) antibody-associated syndromes represent a relatively rare and clinically heterogeneous subtype characterized by prominent temporal lobe involvement and diverse neurological manifestations. GAD65 is an intracellular antigen involved in gamma-aminobutyric acid (GABA) synthesis, and associated autoantibodies have been identified across several autoimmune and neurological conditions with limited diagnostic specificity and variable neurological and neuropsychological presentations. Method: This case report involves a young woman with confirmed anti-GAD65 autoimmune encephalitis (AE), who underwent serial neuropsychological evaluations over a period of two years.

Results

The patient exhibited refractory temporal lobe epilepsy, neuropsychiatric and behavioral disturbance, and a pattern of neuropsychological deficits suggesting prominent temporal lobe dysfunction. Despite being untreated for approximately two years, the patient did not demonstrate a pattern of globally impaired neuropsychological dysfunction. Rather, her profile showed primary, severe impairment in memory and semantically-mediated language functions. What is particularly striking about this case was the severity of the patient's neurocognitive deficits. Specifically, she had a complete amnestic memory syndrome and substantial degradation of semantic knowledge, despite only experiencing seizures for two years, prior to which she was functioning normally.

Conclusions

This case represents an illustrious example of how neuropsychological evaluation played a critical role in documenting the patient's persisting deficits to more accurately tailor treatment recommendations and planning. It also represents a sobering example of the kinds of lasting deficits that can occur without timely diagnosis and treatment.