Vigabatrin-associated brain abnormalities on magnetic resonance imaging (VABAM)
General description
Vigabatrin-associated brain abnormalities on magnetic resonance imaging (VABAM) represent a unique form of drug-induced neurotoxicity observed in patients receiving vigabatrin therapy for spasms. The pathophysiology of VABAM is closely linked to vigabatrin's mechanism of action as an irreversible inhibitor of gamma-aminobutyric acid (GABA) transaminase, which leads to increased central GABA levels.
Clinical manifestations
The clinical presentation of VABAM varies considerably, with the majority of cases being asymptomatic. When symptomatic manifestations occur, they predominantly involve extrapyramidal symptoms and movement disorders. The clinical symptoms associated with VABAM include hyperkinetic disorders, myoclonus, tremor, lethargy, and in rare cases, acute encephalopathy.
T2WI and FLAIR hyperintensity
MRI demonstrates T2WI/FLAIR and DWI hyperintensities in the globus pallidus, thalamus, central tegmental tract of the brainstem, and dentate nucleus. MRI abnormalities may also be seen in the anterior commissure and corpus callosum.