CEREBELLAR ATROPHY AND PHENYTOIN OVERDOSA GE - AN MR-IMAGING STUDY

Phenytoin has been considered a possible cause of cerbellar degenerati on, especially after clinical intoxication. Magnetic resonance provide s the diagnosis of anatomical structures in the posterior fossa withou t the limitation of beam hardening artefacts. The aim of this study wa s to evaluate the relationship of phenytoin medication and cerebellar atrophy in 11 patients with increased serum levels (21.4 mug/ml-95.6 m ug/ml). Five patients had normal cerebellar structures, although three of them had a history of clinical intoxication and all had at least o ne episode of increased serum level of DPH. The remaining six patients had moderate severe cerebellar atrophy (n = 4) and atrophy of the ver mis cerebelli (n = 5). Two of them had never experienced clinical into xication. There was no correlation between the degree of atrophy and s everity of clinical symptoms and evaluation of serum DPH levels (up to four times normal values). There was also no correlation between cere bellar atrophy, duration of epilepsy and frequency of seizures. We con clude that phenytoin overdosage does not necessarily result in cerebel lar atrophy and it is unlikely that phenytoin medication was the only cause of cerebellar atrophy in the remaining patients.