Hydrocephalus is characterised by a disorder in the circulation of cerebrospinal fluid (CSF).
There are several types of hydrocephalus:
- Obstructive: difficulty in the circulation of the liquid through the ventricular cavities, characterised by having a fast clinical course.
- Areabsortive: in this case there is difficulty in the reabsorption of CSF in the arachnoid granulations. Normally the clinical signs in these cases are less acute, even though there may be cases where an emergency situation appears within just a few hours.
- Normal pressure: due to a mixed mechanism, there is an alteration in the circulation of CSF inside the ventricular cavities without there being any mechanical obstruction and, at the same time, certain difficulty in the reabsorption of CSF. In this case the intracranial pressure of the patient (ICP) is normal almost all of the time, thus making this pathology different with hydrocephalus.
There are two large differentiated groups in hydrocephalus:
- Acute hydrocephalus: sudden onset characterised by intense headache, vomiting and finally a decreased level of consciousness. It is considered a neurosurgical emergency.
- Chronic hydrocephalus: its appearance is more masked and associated with headache, poor general condition, visual disorders and on occasions cognitive degeneration and gait disorders.
Although there are stereotyped cases of both these profiles, on many occasions, patients are in an intermediate situation.
Diagnosis is clinical even though imaging tests will be of vital importance when establishing the diagnosis of hydrocephalus by assessing ventricle size and differentiating hydrocephalus from ventriculomegaly where there is no CSF disorder but the increased ventricle size is due to loss of brain tissue.
The treatment of hydrocephalus will be to simplify CSF drainage either by means of a ventricular drainage valve, in the case of areabsortive hydrocephalus and normal pressure hydrocephalus, or by endoscopic premammillary ventriculostomy for obstructive hydrocephalus.