10.3 Hydrocephalus

Question 1

Where is CSF found in the brain?

Answer 1

Subarachnoid space (spiderweb like appearance)

Question 2

What are cisterns?

Answer 2

Certain areas where the space is larger and there is greater separation of the pia & arachnoid

Question 3

Cerebrospinal fluid
General
Production
Absorption
Functions

Answer 3

• Clear colourless fluid, surrounds brain and spinal cord

Production:
- 80 % produced by choroid plexus
- Total volume: 150 mls (50% intracranial ; 50% spinal)
- Rate: 20 mls / hour
- Approximately 450 mls per 24 hours

Absorption:
- Arachnoid Villi / Granulations- extend into dural venous sinuses

Functions:
- Shock absorber for the CNS
- ? Immunological function

Question 4

Flow of CSF

Answer 4

SLIDE 8

Question 5

Hydrocephalus
Define
Causes

Answer 5

Def - Active distension of ventricular system of the brain

Causes
Imbalance between CSF production and absorption:
- Obstruction to normal CSF flow
- Decreased absorption of CSF
- Overproduction of CSF

Question 6

Classify hydrocephalus

Answer 6

Obstructive Hydrocephalus
- Obstruction to CSF flow within the ventricular system

Communicating Hydrocephalus
- Obstruction to CSF flow outside the ventricle system
- CSF communicates with subarachnoid space
- CSF circulation interrupted at level of arachnoid granulations

Question 7

Causes of communicating hydrocephalus

Answer 7

Congenital
- Chiari malformation (abnormality of posterior fossa)
- Dandy Walker malformation (abnormality of posterior fossa)
- Intra-Uterine infection i.e. Toxoplasmosis/CMV/ Coxsackie virus

Acquired
- Subarachnoid haemorrhage (Trauma / Spontaneous)
- Meningitis (TB, bacterial)
- Cerebral venous thrombosis

Question 8

Causes of obstructive hydrocephalus

Answer 8

Congenital
- Aqueduct stenosis (blockage of CSF flow from 3rd ventricle to 4th ventricle)

Acquired
- Tumors (eg: Posterior fossa tumours, Colloid cysts)
- Intraventricular bleed
- Infection

Question 9

Clinical presentation of hydrocephalus of Neonate/Infant

Answer 9

Children with open fontanelles and open cranial sutures (less then 2 years)

• Macrocephaly (enlarged fronto-occipital head circumference)
• Bulging fontanelle
• Diastased cranial sutures
• Dilated scalp veins
• Vomiting, irritability, impaired level of consciousness
• High pitched cry
• Parinauds phenomenon (impaired upward gaze)
• Setting sun appearance
• Cranial nerve fall-out e.g. CN 4 and 6

Question 10

Clinical presentation of hydrocephalus in age >2

Answer 10

• Suppressed level of consciousness (acute)
• Symptoms of raised ICP (Headache; Nausea and vomiting; Papilloedema)
• Cranial nerve palsy
• Developmental delay
• Changes in cognitive function

Question 11

Clinical presentation of hydrocephalus in adults

Answer 11

• Symptoms of raised ICP
• Acute Hydrocephalus (Suppressed level of consciousness)
• Chronic Hydrocephalus (Headache; Nausea and vomiting; Papilloedema)

Question 12

Complications of Hydrocephalus

Answer 12

• Newborns with severe advanced hydrocephalus at birth will likely have brain damage and physical disability.
• Progression of disease
  • Visual disturbance
  • Cognitive dysfunction
  • Gait Abnormality
• Medical Treatment
  • Electrolyte imbalances
  • Metabolic acidosis
• Surgical Procedure
  • Shunt complications (Blockage, infection, over/under drainage, erosion)
  • Post operative haematoma
  • Seizures (due to cortical injury)