communicating hydrocephalus

hydrocephalus /hy·dro·ceph·a·lus/ (-sef´ah-lus) a congenital or acquired condition marked by dilatation of the cerebral ventricles, usually occurring secondarily to obstruction of the cerebrospinal fluid pathways, and accompanied by an accumulation of cerebrospinal fluid within the skull; typically, there is enlargement of the head, prominence of the forehead, brain atrophy, mental deterioration, and convulsions.hydrocephal´ic

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communicating hydrocephalus  that in which there is free access of fluid between the ventricles of the brain and the spinal canal.

noncommunicating hydrocephalus  obstructive h.

normal-pressure hydrocephalus , normal-pressure occult hydrocephalus dementia, ataxia, and urinary incontinence with enlarged ventricles associated with inadequacy of the subarachnoid spaces, but with normal cerebrospinal fluid pressure.

obstructive hydrocephalus  that due to obstruction of the flow of cerebrospinal fluid within the brain ventricles or through their exit foramina.

otitic hydrocephalus  that caused by spread of inflammation of otitis media to the cranial cavity.

posthemorrhagic hydrocephalus  hydrocephalus in an infant following intracranial hemorrhage that has distended the ventricles and obstructed normal pathways for cerebrospinal fluid.

hydrocephalus ex va´cuo  compensatory replacement by cerebrospinal fluid of the volume of tissue lost in atrophy of the brain.

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communicating hydrocephalus

n.

A form of hydrocephalus in which there is a connection between the ventricles and the spinal subarachnoid space, thus allowing cerebrospinal fluid to pass easily from the brain to the spinal cord.

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communicating hydrocephalus

[kəmyo̅o̅′nikā′ting]

Etymology: L, communicans + Gk, hydor, water, kephale, head

a form of hydrocephalus in which there is an increase in cerebrospinal fluid that involves the entire ventricular system and the subarachnoid space. It is caused by an abnormality in the ability to absorb fluid in the subarachnoid space. No obstruction exists in the ventricular pathways.

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communicating hydrocephalus

Normal pressure hydrocephalus Neurology An enlargement of cerebral ventricles due to ↑ secretion and/or ↓ production and absorption of CSF, where the ventricular conduits are open, and the fluid moves freely into the spinal subarachnoid space, but is blocked by obliteration of the subarachnoid cisterns around the brainstem or subarachnoid spaces over the cerebral convexities Etiology Arnold-Chiari malformation, infections–eg, bacterial meningitis, toxoplasmosis, CMV, or other viral meningitides, subarachnoid hemorrhage, ↑ production of CSF–eg, choroid plexus papilloma, Hurler syndrome due to fibrosis in the subarachnoid space, or hypervitaminosis A