CSF
Where is the CSF produced
Choroid plexus within lateral ventricles
What are the three classical symptoms of NPH presentation?
Urinary incontinence, gait apraxia (magnetic gait), dementia (reversible with treatment)
Urinary incontinence caused by disruption of periventricular pathways transmitting inhibitory impulses form the cortex to the sacral micturition center
Apraxia caused by damage to posterior parietal cortex leading to difficulty with motor planning
What is a complication of shunting CSF from the ventricles to the peritoneal cavity (ventriculoperitoneal shunting)?
Shunt malfunction, overdrainage (can result in subdural hematoma), and infection
CSF in the subarachnoid space is reabsorbed through?
arachnoid granulations
which drain into dural venous sinuses
What would cause CSF pressure to rise?
Increase in intracranial volume (with tumors, infarcts causing swelling) or blood volume (with hemorrhages) or CSF volume (with hydrocephalus)
What are signs and symptoms absent in NPH?
Symptoms of increased intracranial pressure such as headaches, nausea, vomiting, visual loss, papilledema
What is the deepest layer crossed when doing a lumbar puncture?
arachnoid mater
(skin, subcutaneous tissue, supraspinous ligament, interspinous ligament, ligamentum flavum, epidural space containing the internal vertebral venous plexus, dura, arachnoid, and finally the subarachnoid space)
The lateral ventricles communicate with the third ventricle through?
Interventricular foramens (foramens of Monro)
In which type of hydrocephalus is due obstruction in the subarachnoid space? Common in the elderly
Communicating hydrocephalus
Caused by chronic reduction in absorption of CSF, accommodated by ventricular enlargement
can be due to subarachnoid hemorrhage, meningitis, choroid plexus papillomas
What hallmark finding on a CT or MRI scan indicates NPH?
Ventriculomegaly in the absence of sulcal enlargement with no obstruction at the level of the third or fourth ventricles
Sulcal enlargement suggests cortical atrophy - seen in Alzheimers
Lumbar puncture is usually performed between which vertebrae?
L3 and L5
at level of cauda equina to sample CSF without damaging spinal cord
place patient in the recumbent position, draw a line between the highest points of the iliac crests to identify L4 vertebral body, then typically insert needle into the L4/L5 space
Where does CSF from the arachnoid granulations drain into?
dural venous sinuses
In which type of hydrocephalus can the CSF of ventricles not reach the subarachnoid space due to obstruction of either interventricular foramens, cerebral aqueduct, or outflow foramens of fourth ventricle?
More common in children
Noncommunicating (obstructive) hydrocephalus
Obstruction of cerebral aqueduct that opens into fourth ventricle
Does normal pressure hydrocephalus result in increased subarachnoid space volume?
no
seen in external hydrocephalus (CSF impairment in subarachnoid space due to hygroma or acute cerebral insults)
What factors suggest lower response following VP shunt?
Moderate to severe dementia, idiopathic NPH (as opposed to known etiology)
The 3rd ventricle drains into the 4th ventricle via?
cerebral aqueduct of Sylvius
Communicating high pressure hydrocephalus is caused by
No obstruction of CSF flow from ventriculi to subarachnoid space
rarely occurs due to increased production of CSF by choroid plexus papilloma
Expansion of the ventricles in normal pressure hydrocephalus results in the distortion of the fibers of ___?
corona radiata
white matter carrying information to cerebral cortex
distortion --> disruption of periventricular pathways transmitting impulses from the cortex to the sacral micturition center --> urinary incontinence
Is there a correlation between improvement following lumbar puncture and VP shunting?
Yes
Patients who improve in gait, cognition, and continence following a large volume lumbar puncture may also have good response to VP shunt - though the correlation is not perfect
The CSF in the 4th ventricle enters the subarachnoid space via?
lateral aperture/foramina of Luschka OR medial aperture/foramen of Magendie