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hydrocephalus
CBN
12
Medical
Graduate
01/08/2011

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Cards

Term
what is the most common way to get a communicating hydrocephalus?
Definition
blockage in the arachnoid granulations which reabsorb CSF (meningitis, SAH)
Term
what is the major difference between communicating and noncommunicating hydrocephalus?
Definition
before doing a spinal tap, you want to r/o obstructive hydrocephalus (via CT scan) b/c that will increase the pressure gradient and possibly lead to herniation.
Term
what is hydrocephalus ex vacuo?
Definition
cerebral atrophy - brain shrinks up leaving an excess of CSF space in brain and skull (as opposed to people with normal hydrocephalus who have big ventricles and NORMAL CSF spaces).
Term
what is the etiology for hydrocephalus?
Definition
SAH (trauma or ruptured cerebral aneurysm) and idiopathic are both 34% respectively, followed by head injury, tumors, prior sx, aqueductal stenosis, meningitis, and misc.
Term
what is normal pressure hydrocephalus (NPH)? **exam question on clinical triad**
Definition
*enlarged ventricles w/normal CSF pressure. clinical presentation: gait disturbance, slowing of thought and actions, dementia, and urinary incontinence. it is caused by resistance to CSF flow w/in the ventricular system or subarachnoid space. **clinical triad: dementia, urinary incontinence, difficulty walking** (wet, wobbly, wild)
Term
what is the etiology for normal pressure hydrocephalus (NPH)? tx?
Definition
idiopathic; possibly secondary to SAH, trauma, tumors, or meningitis. tx: shunting or high volume spinal taps
Term
what is clinical presentation for high pressure hydrocephalus?
Definition
headache, nausea, ataxia, disturbance of vision (papilledema), and neck pain (cerebellar tonsillar herniation).
Term
what characterizes the normal volume of CSF in the CNS?
Definition
at any one time there is about 150 cc's of CSF in the CNS (half of which is in the ventricles), which gets replaced 3x daily (450 cc's made daily).
Term
how is high pressure hydrocephalus diagnosed?
Definition
CT/MRI, also LP (but not if obstructive)
Term
how is high pressure hydrocephalus treated?
Definition
lumbar puncture (temporarily, good for cerebral aneurysm), external ventriculostomy (through temporal bone, good for acute obstructive hydrocephalus), third ventriculostomy, removal of obstruction, and shunting (lumboperitoneal, ventriculoperitoneal [most common], ventriculoatrial, and ventriculopleural)
Term
what are the complications of shunt procedures?
Definition
over/under drainage (most common: hard to get pressure ratio right, flow valves may work better than pressure valves - programmable valves seem to work best via magnets), subdural hygromas, low pressure syndrome, shunt malfunction, seizures, intracerebral hemorrhage, shunt infections, and medical complications
Term
what is an endoscopic third ventriculostomy?
Definition
another way to treat hydrocephalus where a burr hole is made in the top of the head and an endoscope is run into the ventricular system. a hole can be made in the floor of the third ventricle and bypass obstructions which are too hard to remove (don't have to worry about hardware pressure or flow b/c you are dealing w/a contained system).
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