Benign Intracranial Hypertension
(not to be confused with hydrocephalus)
BIH (sometimes called idiopathic intracranial hypertension or pseudotumour cerebri) is a rare condition affecting about one or two in every 100,000 people, most of them women: the usual age of onset is mid-twenties. It can also occur in children, where boys and girls are equally affected, and in older adults. Onset can be sudden or insidious; it may be associated with overweight, but losing weight does not appear to arrest the disease, although American research indicates that a 6% weight loss leads to resolution of the associated papilloedema.
Symptoms
The causes are unclear. However, always present are:
† an abnormality in absorption of excess production of, cerebrospinal fluid (CSF) leading to a build-up of this fluid in the brain;
† increased blood volume in the vessels around the brain;
† swelling of the brain.
The symptoms reported are those usually associated with raised intracranial pressure (ICP); these will commonly include headache,visual disturbances, photophobia, vomiting, problems with balance and spatial awareness, disorientation, loss of short-term memory (sometimes long-term memory loss), "pins and needles" or loss of sensation in hands. In some cases, CSF leaks down the nose. It is important to exclude cerebral tumour as a cause of the symptoms. People with raised ICP may find it difficult to cope with previously learnt everyday tasks, eg handling money or using the telephone. They may be unable to find their way around a previously familiar town: traffic is confusing, they can be unaware of kerb height (sometimes afraid to step off the kerb in case they step into space); crossing the road can be a nightmare.
Diagnosis
Some people need repeated lumbar punctures to remove excess CSF, or the excess CSF may need to be diverted by means of a surgically inserted shunt. In theory, a lumbar peritoneal shunt is the shunt of choice. In practice, the patient may undergo frequent shunt revision, including changing to a ventriculo-peritoneal shunt, or insertion of a lumbar reservoir.
Shunt Risks
Once a shunt is in place, the patient is at risk of those complications sometimes associated with shunting - for whatever reason the procedure is performed. The risks include infection, blockage, and, most commonly in BIH, over-drainage.
Back pain and sciatica or arachnoiditis may occur after lumbar peritoneal shunting.
Surgery should be considered only if there is a deterioration in vision, despite drug therapy or diet; inability to tolerate medication or non-compliance with taking medicines; or severe headaches which are proved to be associated with raised CSF.
Complementary Therapies
After surgery or when CSF pressure is apparently successfully reduced by drugs, headaches may still occur. These can be very debilitating and may need to be treated with combinations of various painkillers. Complementary therapies such as cranial osteopathy, Indian head massage and reflexology are often very helpful, but should only be used if the neurologist or neurosurgeon is in agreement.
For further information on BIH, please contact ASBAH's Services Department. Tel: 01733-555988.
Information supplied by the:
Association for Spina Bifida and Hydrocephalus, 42 Park Road, Peterborough, PE1 2UQ, England
