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9 Cards in this Set
- Front
- Back
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CSF Production
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-80% choroid plexus: carbonic anhydrase produces bicarbonate, chloride ion moves into CSF via countertransport (block with acetazolamide)
-20% cerebral vasculature, pia/arachnoid, ependyma: choroid plexotomy does not eliminate hydrocephalus -CSF production is independent of ICP and BP |
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CSF Absorption
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-venous absorption through arachnoid granulations with 1-way valves into venous sinuses
-not exclusive mechanism: CSF can move through ependyma (also fluid can move in from brain parenchyma), olfactory lymphatics, dural root sleeves |
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Obstructive Hydrocephalus
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Classic: tectal glioma blocks aqueduct of Sylvius, yields lat and 3rd V dilatation with normal 4th V
Atypical: obstruction at level of 4th V outflow tract, all Vs enlarged |
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Communicating Hydrocephalus
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-occurs outside brain: blockage of reabsorption into venous system (SA space or beyond)
-classic: all Vs enlarged (e.g. IVH, SAH) -external hydrocephalus: peds 6-18 mos, benign, CSF builds in frontal SA space not Vs -Normal pressure hydrocephalus: elderly (compliant brain), treatable cause of dementia, ataxia, incontinence -Pseudomotor cerebri (Idiopathic Intracranial Hypertension): obese female, Vs stay same size, ICP rises quickly, non-compliant brain |
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Infant etiology
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Congenital: myelomeningocele/Chiari II, Dandy Walker cyst
Acquired: IVH |
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Adult etiology
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Hemorrhage: SAH/IVH after ruptured aneurysm, trauma
Infection: meningitis, neurocysticercosis Mass lesion: tumor blocking CSF outflow, carcinomatous meningitis blocks SA reabsorption Inflammatory: sarcoidosis (arachnoid level) Venous hypertension: achondroplasia |
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Hydrocephalus - general presentation
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Overt: HA, n/v, sleepiness, dizziness, coma, sunset eyes, CN VI palsy
Insidious: intellectual decline, visual deterioration, papilledema/optic atrophy |
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Hydrocephalus - pediatric presentation
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Overt: irritable, tense fontanelle, bradycardia, distended scalp veins, split sutures, neck stiffness/reduced ROM
Insidious: enlarging head, separated sutures, frontal bossing, missed milestones, feeding intolerance/vomiting |
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Hydrocephalus - natural history/outcomes
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Acute (e.g. hemorrhage, neurocysticercosis)
-rapid Sx progression (herniation) -early death/disability Progressive -macrocephaly, developmental milestones, neurocognitive declien Outcome also affected by delay in diagnosis |
