Hydrocephalus

Question 1

Define Hydrocephalus

Answer 1

Enlargement of the cerebral ventricular system (obstructive or non obstructive)

Question 2

Define the following:
Hydrocephalus ex vacuo
Normal pressure hydrocephalus (NPH)
Communicating vs non-communicating

Answer 2

Hydrocephalus ex vacuo = apparent enlargement of the ventricles as a compensatory change due to brain atrophy

Normal Pressure hydrocephalus (NPH) = Increased CSF but normal pressure. The brain accommodates to the increased CSF fluid volume by becoming smaller

Communicating vs non-communicating
Communication through foramen found in the 4th ventricle between internal/external CSF

Question 3

Aetiology Hydrocephalus

Answer 3

Abnormal accumulation of CSF in the ventricles caused by:

1. impaired outflow of CSF from the ventricular system (obstructive)
   - Lesions of the 3rd ventricle, 4th ventricle or cerebral aqueduct
   - Posterior fossa lesions (tumour, blood) that compress the 4th ventricle
   - Cerebral aqueduct stenosis
2. Impaired CSF resorption in the subarachnoid villi (non-obstructive)
   - Tumours
   - Meningitis (typically TB)

Question 4

Risk factors for Hydrocephalus

Answer 4

> 65
Vascular disease (stroke)
Tumours

Question 5

Symptoms for Hydrocephalus

Answer 5

Obstructive: 
Acute drop in conscious level
Diplopia
Headache
Vomiting
Lethargy

Question 6

Signs of Hydrocephalus on examination

Answer 6

=> Obstructive:
Impaired GCS
Papilloedema
VI nerve palsy (false localising sign of raised ICP)

Neonates: enlarged head circumference, sunset sign (downward conjugate deviation of the eyes)

Question 7

Investigations for Hydrocephalus

Answer 7

CT head: enlarged ventricles

LP is contraindicated in obstructive (causes tonsilar herniation and death), but may needed for NPH
CSF: MC+S, protein, glucose (indicates underlying pathologies e.g. TB)

Question 8

Symptoms and signs of Normal-pressure hydrocephalus

Answer 8

Chronic cognitive decline, falls, urinary incontinence

Cognitive impairment, gait apraxia (shuffling gait), hyperreflexia