Hydrocephalus

Hydrocephalus is an abnormal enlargement of the ventricles of your brain. Cerebrospinal fluid (or CSF) in the ventricles protects the brain and spinal cord. It also contains nutrients necessary for your brain tissues to function. Removal of waste products is another duty of the CSF. The amount of CSF in the ventricles is approximately 150 ml at any given time. The total production of CSF in 24 hrs is approximately 500 ml. Blood absorbs CSF to keep its volume within limits.

Any imbalance between the production of CSF by the ventricle and its absorption by the blood causes hydrocephalus. In children, the ventricles start bulging and increase the size of the head. In adults, it puts a lot of pressure on the brain to cause various symptoms.

The most common treatment for hydrocephalus is shunt surgery. A shunt is an alternative pathway for the CSF to flow out of the ventricles. In this surgery, the surgeon diverts the excess CSF into another part of the body, usually the abdomen. From there, it gets absorbed by the blood to keep its volume within limits.

Causes of Hydrocephalus

Hydrocephalus is a condition and not a disease by itself. It usually occurs when there are blocks in the flow of CSF through the ventricles. Whenever there are blocks, the CSF accumulates in the ventricles and fails to get back into the bloodstream.

Your hydrocephalus may also be congenital or present at birth. The leading causes of congenital hydrocephalus are

• Aqueductal stenosis- The CSF on its way for reabsorption to the bloodstream passes through a duct, by name Aqueduct of Sylvius. Blocks in this passage may be present at birth.
• Type 2 Chiari malformations- In this condition, the cerebellum and brain stem  descends into the spinal canal. It obstructs the flow of CSF through the ventricles.
• Arachnoid cysts- These are bulges in the lining of meninges filled with CSF. 
• Dandy-Walker syndrome- There is an abnormal enlargement in the size of the fourth ventricle due to obstruction in its outlets.

You have acquired hydrocephalus if it develops later in life. The main causes are

• Intraventricular hemorrhage – It occurs mostly in the newborns. Hemorrhage or bleeding in the ventricles leads to the formation of scar tissue that restricts the reabsorption of CSF.
• Meningitis- In this condition, there is an inflammation of the meninges, the protective membrane around the brain and spinal cord. The injury to the meninges causes problems with the flow and absorption of CSF. In India, one of the main causes of meningitis causing hydrocephalus is Tuberculosis.
• Head injuries- Damage or bleeding into the ventricles due to head injuries leads to the formation of scars. These obstruct the flow and absorption of CSF.
• Brain tumors- Tumours may grow into the ventricles to obstruct the flow of CSF.

Symptoms of hydrocephalus

The symptoms of hydrocephalus vary from person to person. It varies with the age of occurrence as well. Most of the symptoms are due to the pressure on the brain by the CSF. Some of the common symptoms of hydrocephalus are as below.

Congenital hydrocephalus

If your newborn has congenital hydrocephalus, some of the common symptoms are

• An abnormally large head at birth, which increases rapidly in size with time
• A large and tender soft spot in the middle of the head 
• Very prominent scalp veins
• Downward deviation of the pupils of the eye or ‘sunset sign.’
• Bouts of vomiting
• Being irritable or very sleepy most of the time
• Sudden seizures 

Acquired hydrocephalus

In children and adults with acquired hydrocephalus, some of the common symptoms are

• Headaches- It is usually worse in the mornings and gets better through the day
• Neck pain
• Nausea and vomiting that is worse in the mornings
• Blurring and double vision
• Difficulty in balancing as well as walking
• Irritability, lack of concentration, confusion
• Bladder problems

Normal-pressure hydrocephalus

If you are an adult with normal pressure hydrocephalus, you will have any of these symptoms, as well as some others.

Problems with walking- You will find it difficult to walk. The biggest challenge will be to take the first step. You may feel as if you are rooted to the spot. Once you start walking, you tend to shuffle your feet than to take proper steps.

Urinary problems- You will need to pass urine very frequently. Most often, the need will be very urgent as well. As it gets worse, you may have a total lack of bladder control

Problems with thinking or Dementia- As the situation worsens, it affects your thought process as well. You will become slow in responding to questions as well as situations.

Types of Hydrocephalus

• Communicating hydrocephalus - In this condition, there is no obstruction to the CSF flow. There is either an increase in production or a decrease in the absorption of the CSF.
• Non-communicating hydrocephalus- There is an obstruction to CSF flow. It causes the ventricles to enlarge and put pressure on the rest of the brain.
• Normal-pressure hydrocephalus- In this, the CSF pressure is normal, but the volume is more. The increased volume enlarges the ventricles. More common in the elderly.
• Hydrocephalus Ex-Vaco- There is an enlargement of the ventricles, while the other tissues in the brain tend to shrink. It is more common in elderly degenerative conditions like Alzheimer’s disease. 

Treatments for hydrocephalus

Surgery is the most common treatment for hydrocephalus. Shunt surgery and third ventriculostomy are the main options.

The goal is to reduce the pressure on the brain by creating a different channel for draining the CSF.

Shunt surgery for hydrocephalus

In this, the doctor will insert a shunt that connects the third ventricle with another part of your body. A shunt system has two catheters or flexible tubes and a valve that connects them. The valve allows the CSF to flow only in one direction, which is away from the ventricle.

The most common area of the body for draining the CSF is the peritoneum, which lines your abdominal cavity. This type of shunt is called a Ventriculo-Peritoneal (V-P) shunt. Other areas of drainage are the pleural space( Ventriculo-Pleural) shunt or the right atrium of the heart(Ventriculo- atrial shunt).

Before surgery- What to do

You will have a few tests to identify the intensity of your symptoms. Tests will also check your general health regarding your fitness for surgery. If you take blood thinners or herbal supplements, you need to stop them a few days before surgery. The same goes for smoking and drinking as well. You will have to report to the hospital the day before surgery.

During surgery

You will have general anesthesia during surgery. Once you are asleep, your surgeon will make a small hole in your skull behind the ear. Through this opening, the surgeon will place one catheter in the ventricle of your brain. 

The other end has a connection to the valve which lies behind the ear. Near the valve is a reservoir which is a small bulge in the catheter. Your doctor can measure your intracranial pressure through the reservoir. It helps to adjust the valves regarding how much CSF should pass through it.

The surgeon will then connect the second catheter to the valve. The remaining part of this catheter will run inside your skin towards the peritoneum lining the abdominal cavity.

Recovery  

You will be in the hospital for two to three days after surgery. You will have pain killers to control the pain for a couple of days after surgery. 

You will have to start walking around your room from the day after surgery. It helps to improve your blood flow, which makes your recovery faster.

Once you are back home, you will have to avoid strenuous activities. Proper wound care is critical to prevent infections. 

Your symptoms will show improvement within a few days of surgery.

Risks and complications of shunt surgery

Apart from the usual surgical risks like pain, swelling, bleeding infections, etc., there are some specific risks. They include

• Increase or decrease in CSF drainage- Both can cause problems for you. Your surgeon will adjust the valves to prevent it. 
• Infections of the shunt
• Shunt Blockage

Endoscopic third ventriculostomy

It is a minimally invasive surgery where your surgeon will use an endoscope to do the surgery. The surgeon will insert the endoscope through a small hole in your skull towards the ventricle. Using miniature surgical instruments, the surgeon will make a small hole at the base of your third ventricle. The CSF will flow from the third ventricle to the fluid chamber below the brain for absorption to the bloodstream. 

The main advantage is that there is no need to have a foreign body like a shunt in your body