Term
| what is the most common way to get a communicating hydrocephalus? |
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Definition
| blockage in the arachnoid granulations which reabsorb CSF (meningitis, SAH) |
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Term
| what is the major difference between communicating and noncommunicating hydrocephalus? |
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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. |
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Term
| what is hydrocephalus ex vacuo? |
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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). |
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Term
| what is the etiology for hydrocephalus? |
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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. |
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Term
| what is normal pressure hydrocephalus (NPH)? **exam question on clinical triad** |
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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) |
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Term
| what is the etiology for normal pressure hydrocephalus (NPH)? tx? |
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Definition
| idiopathic; possibly secondary to SAH, trauma, tumors, or meningitis. tx: shunting or high volume spinal taps |
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Term
| what is clinical presentation for high pressure hydrocephalus? |
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Definition
| headache, nausea, ataxia, disturbance of vision (papilledema), and neck pain (cerebellar tonsillar herniation). |
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Term
| what characterizes the normal volume of CSF in the CNS? |
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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). |
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Term
| how is high pressure hydrocephalus diagnosed? |
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Definition
| CT/MRI, also LP (but not if obstructive) |
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Term
| how is high pressure hydrocephalus treated? |
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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) |
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Term
| what are the complications of shunt procedures? |
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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 |
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Term
| what is an endoscopic third ventriculostomy? |
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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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