Imaging Findings of Vigabatrin-Associated Neurotoxicity in a 12-Month-Old With Infantile Epileptic Spasm Syndrome

Abstract

Infantile epileptic spasm syndrome (IESS), also known as West syndrome, is a rare and severe form of epileptic encephalopathy of infancy. Vigabatrin, a selective, irreversible inhibitor of gamma-aminobutyric acid transaminase (GABA-T), is currently the only FDA-approved medication for the management of IESS. Known associations include neurotoxicity and visual defects. A 12-month-old female with a history of developmental delay and IESS, currently being treated with vigabatrin, was evaluated with magnetic resonance imaging (MRI) after presenting with excessive drowsiness and poor feeding. Imaging findings were significant for new areas of restricted diffusion involving the anterior commissure, medial aspect of the globi pallidi, and the medial thalami bilaterally compared to the patient's MRI prior to starting vigabatrin. These findings suggested vigabatrin neurotoxicity. This case demonstrates the clear relationship between vigabatrin use and the development of stereotypical imaging abnormalities associated with neurotoxicity. It also further illustrates the importance of early recognition and withdrawal of therapy in order to prevent potential long-term side effects.

Keywords: anterior commissure; globi pallidi; infantile epileptic spasm syndrome; medial thalami; mri; neuroradiology; neurotoxicity; restricted diffusion; vigabatrin; west syndrome.

Figure 1. Axial and coronal DWI and ADC brain MRI of the anterior commissure

Axial and coronal images demonstrate hyperintense signal on DWI (a and b) and loss of signal on ADC (c and d) in the bilateral anterior commissure (red arrows) to suggest restricted diffusion. DWI: diffusion-weighted imaging; ADC: apparent diffusion coefficient

Figure 2. Axial and coronal DWI and ADC brain MRI of the thalami

Axial and coronal images demonstrate hyperintense signal on DWI (a and b) and loss of signal on ADC (c and d) in the bilateral paramedian thalami (red arrows) to suggest restricted diffusion. DWI: diffusion-weighted imaging; ADC: apparent diffusion coefficient