Medical literature has reported that use of phenytoin (Dilantin) to control epilepsy and other diseases may be linked to a condition called cerebellar atrophy.

Cerebellar atrophy is a reduction in volume of the cerebellum, the part of the brain that primarily controls balance, movement and coordination.

Acute Phenytoin Toxicity

An article published in 1997 documents the case of a man who went to the hospital with delirium (confused thinking and decreased awareness) and ataxia (loss of voluntary coordination of muscle movements).

A month before the man was admitted to the hospital, he suffered an event and was told to double his dose of phenytoin for one day. After the increased dose, he experienced double vision and mild loss of muscle coordination and control. He was admitted to a hospital and received injections of methylprednisolone.

The man’s family members mistakenly kept giving him his daily dose of Phenytoin during that time, so for 2-3 weeks he was ingesting double the amount of phenytoin per day. The man became increasingly confused and agitated and his ataxia worsened.

When the patient was again admitted to the hospital after the 2-3 weeks of increased phenytoin, he was experiencing frank encephalopathy (obvious signs of brain disease/distress), urinary incontinence, and severe ataxia. MRI findings showed that he had atrophic changes in his cerebellum and his cerebrum (brain as a whole).

An EEG showed a loss of normal alpha activity (alpha waves are present during a wakeful, alert state) and marked bilateral slow waves pointing to abnormal brain function.

After a month’s stay in the hospital, the man had improved overall cognitively, but there were still residual issues with memory and calculation. His speech was still affected by the movement coordination issues and the ataxia persisted.

Six months after the patient was discharged, his EEG had returned to normal but his mild cerebral atrophy had persisted, and his cerebellar atrophy had become severe. His cognitive function was near-normal, but his speech issues and gross ataxia continued to persist.

Phenytoin and Cerebellar Atrophy

This study and several others have observed acute phenytoin toxicity from increased dosage of the antiepileptic drug phenytoin. The more acute, short-term issues usually will resolve after the patient stops taking the drug or begins taking a lower dosage, but cerebellar atrophy may cause persistent damage in some cases of acute toxicity, despite cessation of the drug or lowering the dosage.

Researchers hypothesize that phenytoin itself is toxic to cerebellar neurons, and damage to the cerebellum is not due to the effects of the seizures themselves. Doctors have noted changes in the cerebellum after long-term use of phenytoin medication at levels deemed nontoxic.

Cerebellar atrophy treatment focuses mainly on removing the agent known to be causing the cerebellar damage. In cases of medication, another antiepileptic drug may be substituted, but in some cases, phenytoin is continued because it is the best way to control seizures despite the problems it causes.

Phenytoin Lawsuit Information

If you or a loved one suffered cerebellar atrophy, cerebral atrophy, cerebellar ataxia or other severe side effects as a result of using phenytoin, you may be eligible for legal compensation. An attorney can review your case at no charge and can assist you in understanding your legal options.