Q: My 16 years old son got a head injury in an accident about two month ago. He is improving now and has started standing and walking with minimum support of a person. His MRI report showed increased ventricular size. What does it mean? What are its effects?

A:The brain is surrounded by a fluid layer, which communicates with the cavities (ventricles) deep inside the brain. This fluid called "cerebrospinal fluid" is continuously circulating through small canals. It is produced and absorbed in large quantities everyday.

After a severe brain injury as in trauma, there may be an obstruction to the flow of this fluid, or its production may increase (or absorption may decrease), thereby causing increased pressure within the ventricles, and enlarging them. This is called "post-traumatic hydrocephalus".

If there is any worsening in the patient's condition (gait, speech etc), repeated CT scans of brain (2-3) will give an idea if the pressure is increasing. If so, some medicines may help, but a simple surgical intervention by putting in a tube that will drain the excess fluid from brain to the abdominal cavity (shunting) may be required.