Human brain is enclosed in rigid compartment called the bony skull. Normally the skull contains eighty percent of brain and its interstitial fluid. The rest 10 percent each is occupied by cerebrospinal fluid and blood. The pressure required inside the closed compartment is relatively low. The normal pressure is 5 to 15mm Hg. An increase in the volume of any of the component of brain can cause increase in intracranial pressure.
Increased intracranial pressure can occur due to several reasons. Injury to the brain, brain infection, tumor etc all can increase intracranial pressure. Increased intracranial pressure can be life threatening as this can lead to herniation of brain as well as the spinal cord.
There are several causes for rise in intracranial pressure;
- Increased amount of cerebrospinal fluid.
- Bleeding in brain and formation of hematoma.
- Swelling inside the brain tissue.
- Aneurysm of brain artery.
- Excessive collection of blood in certain part of brain due to brain injury or rupture of a tumor inside the brain.
- Head injury or brain injury.
- Infection in brain such as meningitis and encephalitis.
- Hydrocephalus, which is collection of fluid in brain.
- Stroke and high blood pressure.
- Deficiency of oxygen.
Symptoms And Signs Of Increased Intracranial Pressure
Raised intracranial pressure is fairly easy to identify from the symptoms. One of the few bedrock symptoms of increased pressure in cranium is headache. Patient complains of severe and unbearable headache. The clinical findings are as follows:
- Severe headache
- Vomiting follows along with headache. Initially vomiting relieve headache. Patient has classical projectile vomiting, especially in children and it is not accompanied with nausea. In some patients headache may be mild and the patient only has incessant vomiting.
- Blurred vision in the initial stage which may further cause drop in visual acuity and unless measures are not taken to reduce intracranial pressure, patient may lose his vision permanently.
- Damage to the sixth cranial nerve leading to facial paralysis.
- Reduced alertness or increased drowsiness.
- Problem in balancing the body.
- Behavioral change
- Patient lacks energy
- Stiffness and increased rigidity of neck. Pain in the back of neck.
- Papilloedema; swelling in the back side of eye (optic disc) seen through opthalmoscope. Opthalmoscope is instrument used by eye doctor to see various parts inside the eye.
- Loss of consciousness
- In infants below the age of 12 months, raised pressure in brain causes bulging of the fontanel. It is a soft spot that you can feel on the top of infants head.
Diagnosis And Management Of Increased Intracranial Pressure
Medical history and physical examination both are important for diagnosing any neurological condition. If the doctor suspects raised intracranial pressure, he will recommend certain tests. Complete blood count, lumbar puncture and CT scan of brain will help to diagnose if the intracranial pressure is raised. During physical examination the doctor will also check whether the pupils in eye are reacting to light. Swelling at the back of eye seen through opthalmoscope also indicated rise of pressure inside brain.
One of the important and immediate measures is to lower the intracranial pressure regardless of the cause. The next step of treatment is to address the underlying cause. To reduce pressure, it is important to drain the fluid. The most effective way to do is through a small hole in the skull or through spinal cord tapping.
Further certain medicines are also used to reduce intracranial pressure. Their action is to remove fluid from the body through increased urination. Whenever dieresis is used with the help of medicines, care is taken to maintain electrolyte balance. Anxiety among patients in these patients can cause rise in blood pressure which may be harmful and hence they are mildly sedated.
If tumor is found to be the cause, then it needs to be removed through surgery. In certain cases where drugs and surgery are may not be effective and life is in jeopardy due to increased intracranial pressure, temporary shunt of the cerebrospinal fluid from brain into blood circulation is done with the help of a plastic valve. This method is suitable to buy valuable time. Tuberculous meningitis with hydrocephalus and brain stem tuberculoma which is inaccessible to surgery are examples of such situation.