CSF, Hydrocephalus, Lumbar Puncture

Question 1

Where is CSF found?

Answer 1

Subarachnoid space between arachnoid and pia mater in the brain and spinal cord

Question 2

Role of CSF

Answer 2

Acts as shock absorber
Fills in gaps between brain and skull
Immunological role
Removal of some waste products

Question 3

Specific gravity of CSF

Answer 3

1.007

Question 4

pH of CSF

Answer 4

7.33-7.35

Question 5

Contents of CSF

Answer 5

0-5 WBC
0 RBC
Protein 300mg/l
Glucose 40-80mg/dl

Question 6

Total volume of CSF

Answer 6

150ml - 50% spinal, 50% intracranial

Question 7

Production rate of CSF in adults

Answer 7

0.3-0.5 ml/kg/hour

Question 8

Where is CSF produced?

Answer 8

Choroid plexus in the ventricles

Question 9

Where is CSF absorbed?

Answer 9

Arachnoid villi

Question 10

Components of ventricular system

Answer 10

Lateral ventricles
Foramen of Munro (interventricular foramen)
Third ventricle 
Aqueduct of Sylvius 
Fourth ventricle

Question 11

Meninges are

Answer 11

the membranous coverings of the brain and spinal cord - dura mater, arachnoid mater and pia mater

Question 12

Function of meninges

Answer 12

Provide supportive framework for cerebral and cranial vasculature and protect the CNS from mechanical damage

Question 13

What are the two main dural reflections?

Answer 13

Tentorium cerebelli

Falx cerebri

Question 14

What do the tentorium cerebelli separate?

Answer 14

The cerebellum and brainstem from the occipital loves of the cerebrum

Question 15

Where is the falx cerebri located and what does it separate?

Answer 15

Located in the longitudinal cerebral fissure and separates the two cerebral hemispheres

Question 16

What structures pass through the foramen magnum?

Answer 16

The two vertebral arteries

Question 17

What structures pass through the optic canals?

Answer 17

Optic nerve

Question 18

What structures pass through the foramina ovale?

Answer 18

Mandibular branch of trigeminal nerve

Question 19

What structures pass through the foramina rotunda?

Answer 19

Maxillary branch of trigeminal nerve

Question 20

What structures pass through the jugular foramina?

Answer 20

Sigmoid sinuses, main venous outflow tracts from brain

Question 21

What structures pass through cribriform plate?

Answer 21

Olfactory receptor neurones

Question 22

What structures pass through the superior orbital fissures?

Answer 22

Oculomotor, trochlear, ophthalmic and abducens nerves

Question 23

What structures pass through the internal auditory meati?

Answer 23

Facial and vestibulocochlear nerves

Question 24

What structures pass through the stylomastoid foramina?

Answer 24

Facial nerve

Question 25

What structures pass through carotid canals?

Answer 25

Internal carotid arteries

Question 26

What structures pass through the foramina spinosa?

Answer 26

Middle meningeal arteries

Question 27

What is hydrocephalus?

Answer 27

Accumulation of fluid in the brain resulting in the dilatation of the ventricles

Question 28

Functional classifications of hydrocephalus

Answer 28

Obstructive - blockage outflow from ventricles | Communicating - block at level of arachnoid granulation

Question 29

Congenital causes of hydrocephalus

Answer 29

Chiari malformation Aqueductal stenosis Dandy-Walker malformation

Question 30

Acquired causes of hydrocephalus

Answer 30

``` Meningitis Post-haemorrhagic Neoplastic Post-operative Cerebellar stroke Post-traumatic ```

Question 31

Symptoms and signs of hydrocephalus in infants

Answer 31

``` Cranial enlargement Splaying of cranial surfaces Irritability Poor feeding Full and bulging fontanelles Engorged scalp veins Abducens nerve palsy Perinaud's syndrome Exaggerated reflexes Respiratory problems ```

Question 32

Symptoms and signs of hydrocephalus in older children and adults

Answer 32

``` May be asymptomatic Increased ICP Headaches - worse in morning and on coughing/straining Papilloedema Visual disturbances Gaze abnormality Loss of up gaze - abducens nerve palsy Impaired consciousness ```

Question 33

Medical treatment of hydrocephalus

Answer 33

Acetazolamide

Question 34

Surgical treatment of hydrocephalus

Answer 34

External Ventricular Drain Eliminate obstruction CSF diversion - third ventriculostomy, shunt insertion Endoscopic ventriculostomy

Question 35

Shunts which can be created in the surgical treatment of hydrocephalus

Answer 35

``` Ventriculo-peritoneal Ventriculo-pleural Ventriculo-atrial Ventriculo-subarachnoid Lumbo-peritoneal Cysto-subarachnoid ```

Question 36

What is done in an endoscopic ventriculostomy, and when can it be done?

Answer 36

Create a fistula between third ventricle and subarachnoid cisterns Can only be done in non-communicating hydrocephalus

Question 37

Presentation of normal pressure hydrocephalus

Answer 37

Dementia (potentially reversible) Gait disturbance Urinary incontinence Age > 60

Question 38

Presentation of idiopathic intracranial hypertension

Answer 38

Young obese female Headaches Visual disturbances Papilloedema

Question 39

Treatment of idiopathic intracranial hypertension

Answer 39

Weight loss Acetazolamide CSF diversion Optic nerve sheath fenestration

Question 40

What position should a patient be in to undergo a lumbar puncture?

Answer 40

Foetal position - knees up, neck flexed, pillow between the knees

Question 41

At what vertebral level is a lumbar puncture carried out?

Answer 41

Between L3 and L4

Question 42

Describe basic technique for lumbar puncture

Answer 42

``` Aseptic - clean skin with betadine Local anaesthetic Spinal needle angled towards umbilicus Aim for interlaminar space, through the ligamentum flavum Obtain samples and withdraw needle ```

Question 43

Indications for lumbar puncture

Answer 43

Need to obtain CSF for analysis Measurement of ICP CSF drainage for raised pressure Diagnostic test for normal pressure hydrocephalus

Question 44

Pre-lumbar puncture checks

Answer 44

Patient awake and conscious No focal neurological deficit CT/MRI to rule out intracranial mass lesion Ensure patient isn't on anticoagulation

Question 45

Risks of lumbar puncture

Answer 45

``` Bleeding Infection Nerve root injury Retroperitoneal/intra-abdominal injury Brainstem herniation ```

Question 46

Post-lumbar puncture care

Answer 46

24 hours bed rest Warn about low-pressure headaches Stop LP if patient is developing neurological deficit or becoming unconscious

Question 47

Contraindications for lumbar puncture

Answer 47

Skin infection near LP site Suspicion of increased ICP due to cerebral mass lesion Uncorrected coagulopathy Acute spinal cord trauma

Question 48

Describe CSF in meningitis

Answer 48

Cloudy, turbid Lots of WBC Protein > 1g/l Low glucose

Question 49

Causes of bloody CSF

Answer 49

Traumatic tap | Subarachoid haemorrhage

Question 50

Causes of yellow CSF

Answer 50

Yellow due to blood breakdown products | Most commonly seen in SAH