Brain magnetic resonance imaging markers of vigabatrin-associated neurotoxicity during hyperpyrexia-triggered focal status epilepticus: cause or coincidence?

Vigabatrin is an irreversible γ-aminobutyric acid (GABA) transaminase inhibitor and an effective treatment for infantile epileptic spasms syndrome and refractory focal seizures. Although well tolerated and free from major pharmacokinetic interactions, its use is limited by potential adverse effects, including vigabatrin-associated brain magnetic resonance imaging abnormalities. We present a 9-month-old male patient with developmental and epileptic encephalopathy harboring a POLR2A gene variant, treated with Vigabatrin (Sabril®, Lundbeck, Copenhagen, Denmark) at 125 mg/kg/day, who presented with febrile focal status epilepticus. Brain magnetic resonance imaging (MRI) showed bilateral and symmetrical involvement of the globi pallidi, subthalamic nuclei, cerebral peduncles, and dorsal pons, characterized by diffusion restriction (diffusion-weighted imaging (DWI) hyperintensity and corresponding apparent diffusion coefficient (ADC) reduction). These MRI abnormalities resolved following discontinuation of vigabatrin. This case highlights the need for clinical awareness and regular neuroimaging during vigabatrin therapy, as MRI abnormalities are often asymptomatic but can occasionally coincide with acute neurological events, especially in the immature brain. Close monitoring is essential to detect early neurotoxicity signs and to consider therapy withdrawal when appropriate, when a direct causal relationship remains uncertain.