CSF, Hydrocephalus, Lumbar Puncture Flashcards
what is hydrocephalus?
refers to a general condition whereby there is excess Cerebro-Spinal Fluid (CSF) within the intracranial space and, specifically, the intraventricular spaces within the brain
where is the majority of CSF produced?
choroid plexus
where is the choroid plexus located
lateral ventricles
how much CSF is produced everyday?
450 and 600 cc’s
what is the CSF pathway
From the lateral ventricle (remember, there are two…one on each side), CSF travels through the foramen of Monro into the 3rd ventricle
(midline), then passes through the Cerebral Aqueduct [of Sylvius] into the 4th ventricle.
It then exits the 4th ventricle through either of two Foramina of Luschka (“L” is for Lateral/Luschka) or the single Foramen of Magendie (“M” is for Midline/Magendie).
After exiting the 4th ventricle, the CSF flows through the subarachnoid space over and around the brain and spinal cord, and is eventually reabsorbed into the venous (blood) system through numerous arachnoid granulations along the dural venous sinuses (especially the superior sagittal sinus).
is CSF production passive or active?
active- uses ATP
is CSF reabsorption passive or active?
passive- driven by pressure gradient between the intracranial space and venous system
what are the 2 major distinctions of hydrocephalus?
Communicating Hydrocephalus (CoH) Also known as “non-obstructive” hydrocephalus Non-communicating Hydrocephalus (NCH) Also known as “obstructive” hydrocephalus
definitions of non communicating and communicating
If the CSF pathway is “open from start to finish,” meaning CSF can travel freely from the choroid plexus to the arachnoid granulations, then you have “no obstruction” and a communicating hydrocephalus.
If the CSF can’t travel freely from start to finish, then you’ve got an “obstruction” and non-communicating hydrocephalus.
what is the result of CoH?
the ventricular system dilates uniformly, and ICP rises.
signs and symptoms of CoH
In young children whose cranial sutures have not yet fused, you can see disproportional increase in head circumference compared to the rest of the face/body or failure to thrive
In children with fused sutures/adults, hydrocephalus manifests with symptoms of increased intracranial pressure;
H/A, N/V, papilledema, gait disturbance, 6th cranial nerve palsy, upgaze difficulty, etc
eitiology of CoH?
Infection (incidence after bacterial meningitis can approach 30%)
Subarachnoid Hemorrhage (blood and blood breakdown products cause scarring of arachnoid granulations)
Post-operative
Head trauma
causes of NCH
Aqueductal stenosis Tumors/Cancers/Masses Cysts Infection Hemorrhage/hematoma Congenital malformations/conditions
what woudl show on a radiograph if someone had NCH?
dilation of the temporal horns of the lateral ventricles (arrows). In most younger and middle-aged patients, these should be almost invisible.
The third ventricle will become ballooned
Lateral ventricle size increase
Peripheral sulci effaced
what is the treatment for hydrocephalus?
Treatment for Hydrocephalus remains surgical.
External Ventricular Drain (EVD - catheter passed through the patient’s scalp and skull into lateral ventricle, that drains CSF to a collection system kept at the patient’s bedside).
For communicating hydrocephalus, the mainstay of treatment is shunt placement.
Ventriculo-peritoneal is most used.
Lumbar-peritoneal sometimes utilized, though overdrainage is a problem.
Ventriculo-atrial can also be considered in cases of peritoneal failure
what is the classic triad for normal pressure hydrocephalus?
wet, wobbly and wacky
what is normal pressure hydrocephalus treatment?
Programmable VP shunt placement.
LP shunts tend to overdrain and are difficult to assess and revise.
what are the indications for lumbar puncture?
Meningitis Meningoencephalitis Subarachnoid hemorrhage Malignancy – diagnosis and treatment Idiopathic Intracranial Hypertension Other neurologic syndromes Infusion of Drugs or contrast
what are the contraindications for lumbar puncture?
Unstable patient with cardiovascular or respiratory instability
Localized skin/soft tissue infection over puncture site
Evidence of unstable bleeding disorder
Platelets < 50,000 or clotting factor deficiency
Increased intracranial pressure
what comes on a CSF tray?
Anesthetic such as:
Topical - EMLA, Elamax, Zylocaine cream
Lidocaine 1% with 25 gauge needle and syringe
Povidone-iodine solution & sponge wand
Drapes, gauze, and bandages
Manometer, stopcock and tubing in non-infant kits
Spinal needle, usually 22 gauge
complications of lumbar puncture
Headache Uncommon in < 10 y/o Apnea (central or obstructive) Back pain Occasionally with short-lived referred limp Disc herniation if needle advanced too far Bleeding or fluid leak around spinal cord Infection, pain, hematoma Subarachnoid epidermal cyst Ocular muscle palsy (transient) Nerve Trauma Brainstem herniation
risk factors for spinal headache
female, age 18-30, lower BMI,
how do you prevent spinal headache?
Passing needle bevel parallel to longitudinal fibers of dura
Replacing stylet before removing needle
Using small diameter needles
Using atraumatic needles
