A case of anti-glutamic acid decarboxylase(GAD) antibody-associated temporal lobe epilepsy presenting with suspected ictal bradycardia syndrome

Abstract

Temporal lobe epilepsy is sometimes associated with bradycardia and asystole, which is known as ictal bradycardia (IB) syndrome. Herein, we report a case of a patient with an intractable temporal lobe epilepsy with antibodies directed against glutamic acid decarboxylase (anti-GAD-Abs), who repeatedly experienced sudden bradycardic attacks (BAs). A 30-year-old woman with a history of left temporal lobe epilepsy and extremely high anti-GAD-Abs titers developed high fever and dyspnea. She was admitted under a diagnosis of septic pyelonephritis and subsequent acute kidney injury. During treatment, she experienced three episodes of BAs without any warning signs. All of the BAs were treatment resistant, and the second attack even occurred in clusters. Despite intensive care treatment, including a catecholamine injection, a third BA recurred, causing her death. A review of her electrolyte levels throughout the three BAs revealed that she had moderate hypophosphatemia during the second and third attack, which possibly lessened the threshold level of epilepsy. The patient’s epilepsy was intrinsically difficult to control, therefore we assumed that the BAs were recurring due to IB. When IB is suspected in an intractable epilepsy patient, electroencephalogram monitoring allows us to make a diagnosis of IB syndrome. Additionally, external pacing therapy should be considered until epilepsy is controlled.