Cerebellar atrophy is a brain side effect that sometimes shows up in patients who take Dilantin to treat epilepsy.

It’s a type of focal cerebral atrophy that affects the cerebellum, an area of the brain that carries a lot of responsibility for control of movement.

Symptoms of Cerebellar Atrophy

Patients who develop cerebellar atrophy can develop a set of movement symptoms that is often referred to as ataxia.

Typically, these patients will have trouble with their posture, gait or balance: walking and running may become difficult, and they might find themselves tripping or falling.

Tasks that involve fine motor coordination can also be affected. These tasks include many everyday activities like preparing food or putting on clothes. Speaking and swallowing food may also be impaired.

In addition to the movement symptoms, ataxia sometimes also causes cognitive and mood problems, because the cerebellum also plays a role in some types of thinking.

Some patients have reported difficulty with “executive functions” like making plans or keeping their thoughts in order. Others have reported emotional symptoms like irritability, anxiety or depression.

Cerebellar Atrophy as a Dilantin Brain Side Effect

Years ago, researchers thought cerebellar atrophy might only be a brain side effect of the epilepsy itself. More recent research suggests there may be a connection between cerebellar atrophy and long-term use of Dilantin.

A study published in 2002 sought to clear up whether cerebellar atrophy was a brain side effect of Dilantin or of epilepsy itself – or whether it was related to both those factors.

Researchers examined the magnetic resonance imaging records of 56 epilepsy patients who had been treated with Dilantin, referred to in the study by its generic name phenytoin.

Over 35 percent of these patients showed signs of cerebellar atrophy in their imaging studies. After statistical analysis, the only factor significantly associated with cerebellar atrophy was the length of time the patient had been treated with Dilantin.

The researchers concluded that while the duration of the patient’s epilepsy could still influence their cerebellar atrophy, that factor was clearly less significant than how long the patient had been exposed to phenytoin.

A case study published in 2000 tells the story of a very young epilepsy patient who developed cerebellar atrophy after taking Dilantin. At three-and-a-half years old, the boy was diagnosed with epilepsy and was prescribed Dilantin. One year later, he had started to exhibit an unsteady gait and difficulty with speech.

Imaging studies showed the boy had marked cerebellar atrophy. The level of Dilantin in the boy’s blood was above the level considered suitable for treatment, which the researchers attributed to the fact that his mother had given him pills she cut by hand with a knife. The boy was taken off Dilantin, but even months later his symptoms had not improved.

Even if a patient gets good control of epilepsy symptoms by using Dilantin, the effects of this brain side effect could conceivably outweigh the benefits of treatment.

Cerebellar atrophy threatens to inhibit the patient’s ability to do ordinary, everyday tasks – particularly those involved in working and earning income.

Expensive physical or occupational therapy may also be necessary, potentially compounding the patient’s losses at a time when they may be less able to earn wages.