Noncommunicating hydrocephalus or internal hydrocephalus (Congenital)
- result from congenital abnormalities in the ventricular system
- mass lesion such as tumor that compresses the structures of the ventricular system
- impaired absorption of the CSF from the subarachnoid space occurs when an obstructive process disrupts its flow through the subarachnoid space
- fluid is then prevented from reaching the convex portion of the cerebrum, where the arachnoid granulations are located.
- Hydrocephalus from impaired absorption may be caused by adhesions from inflammation as with meningitis or subarachnoid hemorhage, compresion of the subarachnoid space by a mass
- congenital abnormalities of the subarachnoid space
- high venous pressure within the sagital sinus
- d/t subarachnoid hemorrhage
- d/t developmental malformation
- d/t neoplasm
Normal-Pressure Hydrocephalus (Acquired)
- occurs mostly in late middle age
- caused by arachnoid adhesions that obstruct the subarachnoid space
- most frequently seen as a complication of head injury
Tx: Management of intracranial pressure with surgical shunt incision.