Hydrocephalus

Question 1

What is hydrocephalus?

Answer 1

XS CSF in the intracranial space and specifically in the interventricular space

Question 2

Two types of hydrocephalus

Answer 2

Communicating: related to problems with reabsorption

Non-communicating: due to obstruction in CSF pathway

Question 3

What happens during communicating hydrocephalus

Answer 3

• CSF can pass freely from the choroid plexus to the arachnoid granulations
• Causes there to be XS CSF in the Brain as more CSF produced than reabsorbed
• This causes the ventricular system to dilate unilaterally
• This causes ICP to increase

Question 4

Aetiology of communicating hydrocephalus

Answer 4

Infection e.g. meningitis
SAH
Post-op
Trauma

Question 5

Signs and symptoms of communicating hydrocephalus

Answer 5

-In young children whose sutures have not fused:
Skull is a lot rounder than face
Failure to thrive

-In children with fused sutures:
Increased ICP 
Papilloedema 
Gait disturbance 
6th cranial nerve palsy 
Upgaze difficulty 

When it is an emergency:
Patients decline rapidly
May become obtunded
May require intubation

Question 6

Aetiology of non-communicating hydrocephalus

Answer 6

Masses 
Stenosis 
Cysts 
Infection 
Hemorrage/hematoma 
Congenital malformations

Question 7

Signs/symptoms of non-communicating hydrocephalus

Answer 7

First sign is of the dilation of the temporal horns (inferior horns) of the lateral ventricles 
These should be invisible 
On imaging: 
-Lateral ventricle increase in size 
-Third ventricle becomes ballooned 
-Evans ration >30%

Question 8

What is Evans ratio?

Answer 8

maximum width of calvarium/ maximum width of anterior horns

Question 9

Acute treatment of hydrocephalus

Answer 9

Requires placement of a external ventricular drain (passes from skull into the lateral ventricle and drains CSF)
Infection risk is high
Not permanent

Question 10

Treatment of communicating hydrocephalus

Answer 10

Shunt placement:
Most common is ventriculo-peritoneal
Lumbar-peritoneal tends to have problems with overdrainage
Ventriculo-atrial

Question 11

Treatment of non-communicating hydrocephalus

Answer 11

Shunt can be avoided by removing primary lesion

Third ventriculostomy is an option - usually conjoined operation with the placement of a VP shunt

Question 12

Success rate of shunts

Answer 12

50% failure within first 5 years of placement

• Usually mechanical disruption
• Infection

Question 13

Importance of normal pressure hydrocephalus

Answer 13

Rare preventable causes of dementia

Question 14

Symptoms of NPH

Answer 14

-WET, WOBBLY, WACKY : urinary incontinence, gait disturbance and dementia
-Communicating hydrocephalus
-With LP:
normal opening
Improves with removal of CSF

Question 15

Treatment of NPH

Answer 15

Ventriculo-peritoneal shunt:
More likely to resolve the earlier the problem is recognised
Order of symptoms it is most likely to resolve: gait> incontinence> dementia