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A 64 year-old man presented with nausea, vomiting and right sided ataxia. CT scan showed a right cerebellar stroke. Two days later he abruptly deteriorated, and became obtunded with decerebrate posturing. |
| Non-Communicating Hydrocephalus:
Axial CT scans. Note the hypodensity in the right cerebellum (left image) denoting the subacute stroke.
In ischemic stroke, maximal edema typically occurs on day 2 or 3. In this case, one can see that the stroke has swelled and compressed
the fourth ventricle, resulting in acute non-communicating hydrocephalus (right image). The third ventricle
which normally has the shape of a slit has now become round. The temporal horns of
the lateral ventricles have also become markedly enlarged. Note that no sulci are seen over the
convexities as they have been effaced due to the increased pressure. This
situation requires emergency neurosurgery and ventricular shunting
to reduce the pressure.
Hydrocephalus is recognized as enlarged ventricles out of proportion to the amount of cerebral atrophy. Non-communicating (obstructive) hydrocephalus occurs when the ventricular system is not in continuity with the subarachnoid space. Most often, the site of the blockage in non-communicating hydrocephalus is at the cerebral aqueduct, but rarely can occur at the foramen of Monro, the third ventricle, or the outlet of the fourth ventricle. Acute non-compensated, non-communicating (obstructive) hydrocephalus is a neurosurgical emergency as the non-compensated hydrocephalus results in a progressive increase in intracranial pressure, which if left unchecked will result in herniation and brain death. It is potentially treatable by shunting. |
Revised
11/29/06
Copyrighted 2006. David C Preston