CSF, Hydrocephalus, Lumbar Puncture

Question 1

What is the CSF volume in the body

Answer 1

150ml

Question 2

What is hydrocephalus

Answer 2

Abnormal accumulation of CSF within the ventricles of the brain (presents with raised ICP - medical emergency)

Question 3

What are the causes of subnormal CSF reabsorption (2)

Answer 3

Obstructive hydrocephalus = block in ventricular system
Communicating hydrocephalus = obstruction of CSF absorption at level of arachnoid granulations

Question 4

What is the cause of CSF overproduction hydrocephalus

Answer 4

Rare tumours of choroid plexus (often combined with abnormal reabsorption)

Question 5

What is the cause of congenital hydrocephalus

Answer 5

Aqueduct stenosis (usually in infancy)

Question 6

What is the causes of acquired hydrocephalus (3)

Answer 6

Infections (most common cause of communicating hydrocephalus)
Post-haemorrhagic (2nd most common cause)
Secondary to masses (lesions)

Question 7

What are some signs and symptoms of hydrocephalus in older children and adults

Answer 7

Symptoms of raised ICP (papilledema, morning headaches, headaches associated with vomiting, gait changes, upgaze palsy, double vision)
- symptoms may have gradual onset or very sudden in acute hydrocephalus

Question 8

What are some signs and symptoms of hydrocephalus in young children (6)

Answer 8

Abnormalities in head circumference
Cranial enlarges faster than facial growth
Poor head control
Nausea and vomitting
Upward gaze
Fontanelle full and bulging

Question 9

What are the investigations for hydrocephalus

Answer 9

CT
MRI
ultrasound (only in small babies as the Fontanelle sutures are still open)

Question 10

In what kind of hydrocephalus would lumbar puncture and lumbar drain be a safe and effective treatment

Answer 10

Communicating hydrocephalus

Question 11

What are the treatment options for obstructive hydrocephalus

Answer 11

External ventricular drain
Endoscopic third ventriculostomy

Question 12

Describe relevant anatomy in performing a lumbar puncture

Answer 12

Patient in lateral recumbent position
Line connecting the posterior iliac crest will intersect the midline at the L4 spinous process (enter subarachnoid space below termination of spinal cord)

Question 13

Where does the spinal cord terminate in adults and in children

Answer 13

Adults = L1/L2
Children = T12/L1

Question 14

What are the indications for performing a lumbar puncture (2)

Answer 14

Safe to do so in communicating hydrocephalus
Safe to do it as long as there is no increased ICP secondary to a mass lesion or obstruction of CSF in cranial vault

Question 15

What are the contraindications to performing a lumbar puncture (5)

Answer 15

• Focal neurological deficit, not including cranial nerve palsies (Focal symptoms or signs suggest a focal brain mass) - New-onset seizures
• Papilloedema
• Abnormal level of consciousness (GCS <10) (Reduced conscious level suggests raised ICP)
• Severe immunocompromised state