This is a buildup of cerebrospinal fluid (we call it CSF) in the brain's ventricles. The ventricles are natural spaces found deep in the brain. CSF is a fluid that flows in and around your brain and spinal nerves. But extra fluid makes the ventricles swell, raising pressure in your skull. This pressure can harm your brain.
What causes the CSF buildup? Most often, it happens when something stops the fluid from draining from the brain. It may also happen if your body makes too much CSF, or doesn't absorb it properly.
What are the symptoms? Well, it depends on the person's age. In an infant or a toddler, it can make the head swell. That's because the bones of their skull have not yet fused. It can cause things like poor appetite, irritability, vomiting and seizures. An older child may say they have a headache. They may have problems with balance and coordination. And they may have other issues.
In adults and the elderly, it may cause other issues. It can harm vision and sleep. It can make a person pee a lot, or lose control of their bladder. It can also affect memory and reasoning. Ask your doctor for a full list of symptoms.
How do we treat it? Most commonly, we surgically implant a drain called a "shunt" to carry extra CSF away from the brain. Your doctor will create a plan that's right for you.