Q: I am 28 years old and had a traumatic brain injury about 12 months ago and recovered well. I had a diffuse axonal injury and micro-haemorrhaging of the brain stem. When I had the injury, I had a seizure, for which I was put on Phenytoin 300 mg daily and I am still on it. I had an MRI scan last week and got the results today, they said that there is no new problem or damage; just things left from the original injury. However, the doctor said that I had cerebellar atrophy. I have an EEG booked for next week. What is cerebellar atrophy? What causes it and what are the future complications due to this?

A:Cerebellum (literally means little brain) hangs around the stalk of our brain (brain stem) lying at the back. There are two of them. They are primarily responsible for coordination of movements, vision and all other motor activities of the body. The term atrophy means wasting. So, cerebellar atrophy means wasted small cerebellum. It usually occurs during long standing degenerative diseases (many of them hereditary), which presumably you don't have. Following traumatic brain injury, cerebellar atrophy may result after a reasonable period of time especially if direct injury, haemorrhage or lack of oxygen (hypoxia) is present. Drugs and some toxins can also cause it. However, radiologically seeing a small, atrophied cerebellum means nothing unless you have clinical symptoms of in-coordination due to cerebellar dysfunction. Phenytoin use in long term can cause cerebellar damage and atrophy and this anti-epileptic should preferably be avoided if cerebellum is a suspect.