Early Institution of Immunotherapy Alters the Course of Temporal Lobe Epilepsy With GAD65 Antibody: A Clinical Report

Glutamic acid decarboxylase 65 (GAD65) antibody-associated temporal lobe epilepsy (GAD65-TLE) is a rare form of autoimmune-associated epilepsy characterized by medically refractory seizures and cognitive decline. Diagnosis typically requires antibody testing and clinical correlation, and treatment options include immunotherapy and antiseizure medications (ASMs). However, many patients experience persistent or worsening symptoms despite ongoing treatment.

A 20-year-old woman presented with mild cognitive impairment and focal aware seizures that gradually progressed in frequency and severity. A diagnostic workup revealed GAD65-TLE, and the patient began treatment with intravenous methylprednisolone infusions and antiseizure medications within 6 months of her presentation. After 20 months of treatment, the patient was on stable doses of levetiracetam and lamotrigine and finished tapering immunosuppressive therapy with methylprednisolone. The frequency of her focal aware seizures significantly decreased, whereas the focal impaired aware and focal bilateral tonic-clonic seizures resolved. The patient was able to return to all of her previous daily activities.

In patients presenting with new-onset seizures characterized by unusual semiology and frequent focal aware seizures, it is crucial to consider GAD65-TLE in the list of potential diagnoses. Delayed diagnosis may lead to resistance to both ASMs and immunotherapy. This case report emphasizes how prompt identification and early initiation of immunotherapy can significantly impact the course of the disease.