MISCELLANEOUS CAUSES OF HEADACHES: HYDROCEPHALUS
Cerebrospinal fluid (CSF) is formed inside the ventricles, which are spaces deep inside the brain. From here it moves slowly outwards and downwards, passing out through a narrow canal to enter the space around the outside of the brain and spinal cord. It is then gradually absorbed into the veins which line the inside of the skull.
The weak link in the chain is the canal connecting the ventricles with the outside of the brain. If this is obstructed, CSF cannot get out from the inside of the brain. Unfortunately, this fluid continues to be formed, gradually increasing the pressure within the brain, blowing it up like a balloon. This condition is called hydrocephalus, commonly known as ‘water on the brain’.
Conditions that obstruct the outflow of CSF include a congenital narrowing of the drainage channel; a tumour pressing on the channel; or, after meningitis, which scars the canal so that it become blocked and can no longer drain CSF properly.
Hydrocephalus is a disease which affects those at the extremes of life. It is common in young children because they are more prone to those conditions which obstruct The outflow canal. These are congenital malformations, meningitis and brain tumours. Hydrocephalus also occurs in adults, but is significantly different from that in children. Most childhood tumours are tumours of brain tissue itself, whereas in adults many tumours are secondary growths spreading from other parts of the body. Hydrocephalus in adults gives severe headaches, with vomiting and confusion. Again, the skull is unyielding, and the brain tissue is severely compressed by the rise of pressure. Treatment is difficult. If by any lucky chance it is due to a benign tumour obstructing the outflow canal then it can be removed, but often hydrocephalus in adults occurs from inoperable malignant tumours.
Benign intracranial hypertension
Ultra-cranial hypertension causes generalised swelling in the brain, due to the presence of excess water, a condition called oedema. Its symptoms are very similar to the effects of hydrocephalus in an adult – there is headache, vomiting and impairment of consciousness.
Benign intra-cranial hypertension responds well to steroids and they can often keep it completely under control.
Lumbar puncture headache
The brain floats inside the skull – moored in the cerebrospinal fluid (CSF). If CSF is drawn off, then the brain tends to sink down inside the skull, pulling on its moorings – and this is exceptionally painful.
Normally, of course, this doesn’t happen. However, when a lumbar puncture is performed some of the CSF fluid is drawn off. This causes the brain both to tug on its moorings and also to swell slightly to make up for the fluid that has been drawn off. This hurts. It is quite common for a headache to develop for twenty-four hours, following a lumbar puncture, while the body is replenishing the level of CSF. During this time the patient is encouraged to lie still and Hat (he usually wants to) and the headache is usually lessened if the patient stays in this position, lying in bed.
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