CSF, hydrocephalus and lumbar puncture

Question 1

What is hydrocephalus?

Answer 1

General condition whereby there is excess CSF in the intracranial space and specifically, interventricular spaces within the brain causing dilation of ventricles and a wide range of symptoms

Question 2

What ventricles is the majority of CSF produced and by which structure?

Answer 2

lateral, 3rd, 4th

choroid plexus

Question 3

Briefly describe CSF production

Answer 3

metabolically active

sodium pumped into subarachnoid space and water follows

Question 4

How much on average does an adult brain make of CSF per day?

Answer 4

450-600 cc’s

Question 5

At any moment how much CSF is present and with how much being in the ventricles?

Answer 5

150cc

25cc

Question 6

CSF pathway

Answer 6

lateral ventricle - foramen of munro - 3rd ventricle - cerebral aqueduct - 4th ventricle - foramina of Luschka or foramen of Magendie - subarachnoid space - over and around brain and spinal cord - arachnoid granulations

Question 7

Where are the arachnoid granulations found?

Answer 7

Along dural venous sinuses

Question 8

Is CSF resorption active or passive and what does it rely on?

Answer 8

passive

pressure

Question 9

Difference between communicating and non communicating hydrocephalus

Answer 9

Non communicating - obstruction in CSF pathway

Question 10

What is the main problem in communicating hydrocephalus?

Answer 10

CSF resorption

Question 11

What happens to the ventricular system and ICP in CoH?

Answer 11

dilates

increases

Question 12

Signs in children with CoH

Answer 12

failure to thrive, head disproportionate to body

Question 13

Signs/symptoms in adults with CoH

Answer 13

headache, papilloedema, gait disturbance, 6th nerve palsy , upgaze difficulty

Question 14

Causes of CoH

Answer 14

infection - bacterial meningitis
subarachnoid haemorrhage
post-operative, head trauma

Question 15

Causes of NCoH

Answer 15

aqueductal stenosis 
tumours/cysts/cancers/masses
infection 
haemorrhage/haematoma
congenital malformations/conditions

Question 16

3 findings on radiography with hydrocephalus

Answer 16

Dilation of temporal horn of lateral ventricle
3rd ventricle balloons
peripheral sulci wiped out

Question 17

What is Evan’s ratio used for?

Answer 17

ventriculomegaly

Question 18

Main treatment method for hydrocephalus ie medical or surgical?

Answer 18

surgical

Question 19

What does acute hydrocephalus require for treatment?

Answer 19

EVD - external ventricular drain

Question 20

What is usually required after an EDV?

Answer 20

permanent shunt

Question 21

Main treatment for CoH

Answer 21

shunt placement

Question 22

Main treatment for NCoH

Answer 22

remove obstruction

Question 23

What is 3rd ventriculostomy and what type of hydrocephalus can it be used in?

Answer 23

hole between 3rd and 4th ventricle

NCoH

Question 24

Why do VP shunts fail?

Answer 24

infection, over/under drainage, occlusion, skin erosion

Question 25

Why is normal pressure hydrocephalus important?

Answer 25

Rare and preventable/reversible cause of dementia

Question 26

Classic triad of normal pressure hydrocephalus

Answer 26

wet - incontinence wobbly - gait disturbance whacky - progressive dementia

Question 27

How does normal pressure hydrocephalus appear in scans?

Answer 27

CoH

Question 28

Investigations of normal pressure hydrocephalus

Answer 28

MMSE gait assessment Lumbar puncture

Question 29

Treatment of normal pressure hydrocephalus - why is a LP shunt not used?

Answer 29

programmable VP shunt | tend to overdrain

Question 30

Most likely symptoms to improve in normal pressure hydrocephalus

Answer 30

gait - incontinence - memory

Question 31

Indications for lumbar puncture

Answer 31

Meningitis, meningoencephalitis malignancy subarachnoid haemorrhage infusion of drugs/contrasts ETC

Question 32

Some contraindications of lumbar puncture

Answer 32

``` unstable patient with CVS and resp instability localised infection over puncture site unstable bleeding disorder Raised ICP CT to rule out cerebral mass ```

Question 33

List some equipment needed for a lumbar puncture (do not need to be specific)

Answer 33

``` anaesthetic eg topical, lidocaine drapes, gauze and bandages sponge wand and sterile solution manometer, stopcock and tubing spinal needle ```

Question 34

How do you avoid hitting blood vessels on lumbar puncture?

Answer 34

stylet pointing up

Question 35

What is manometry used for in lumbar puncture?

Answer 35

measure pressure (opening pressure)

Question 36

Volume of CSF collected and what 3 vials samples?

Answer 36

1ml | culture and gram stain, glucose and protein, cell count

Question 37

What position is an infant put in for lumbar puncture and what is the disadvantage?

Answer 37

seated | cannot measure pressure accurately

Question 38

2 reasons for paramedian/lateral approach in lumbar puncture

Answer 38

calcifications from previous lumbar punctures | anatomic abnormalities

Question 39

Complications of lumbar puncture

Answer 39

headache, apnea, bac pain, nerve trauma, brainstem herniation, bleeding, infection, cyst

Question 40

Most common complication of lumbar puncture and groups most commonly affected

Answer 40

headache | female, 18-30, low BMI, history of headache

Question 41

Prevention methods of headache post lumbar puncture

Answer 41

use small diameter needle | pass needle parallel to longitudinal nerve fibres

Question 42

What does nerve root trauma feel like and how is it investigated+treated

Answer 42

electric shock | CSC, EMG

Question 43

How would herniation during lumbar puncture present?

Answer 43

altered mental status, cranial nerve abnormalities

Question 44

How is herniation mid lumbar puncture treated?

Answer 44

remove needle, elevate bed, mannitol and intubate | surgery

Question 45

What causes an epidermal inclusion cyst

Answer 45

skin driven into spinal space

Question 46

If lumbar puncture fails what are some alternatives?

Answer 46

image guided ask colleague eg anaesthetics, neurology cisterna magna tap