Hydrocephalus and Raised ICP

Question 1

What is hydrocephalus?

Answer 1

Increased volume of cerebrospinal fluid (CSF) occupying the cerebral ventricles.

Usually due to impaired absorption but sometimes due to overproduction.

Question 2

What is non communicating hydrocephalus?

Answer 2

Non communicating (obstructive) is when there is an obstruction within the ventricles or between the ventricles and the sub arachnid space. Leading to raised CSF levels.

Question 3

What is communicating hydrocephalus?

Answer 3

Communicating is when there is communication (drainage) between the ventricles and sub arachnoid space but there is a problem with drainage outside the ventricular system such as:

• reduced absorption
• blockage of the venous drainage system
• increased CSF production

Question 4

What is external hydrocephalus?

Answer 4

Also known as benign external hydrocephalus (BEH) or Benign enlargement of the subarachnoid spaces in infancy (BESSI)

As the name implies, a benign enlargement of subarachnoid spaces seen in infancy. Thought to maybe be due to delayed development of the arachnoid villi (involved in drainage) at the sagital sinus.

Question 5

What are the signs of raised ICP in infants?

Answer 5

• Rapid increase in head circumference or head circumference is in the 98th percentile for the age or greater.
• Dysjunction of sutures
• Tense fontanelle
• Increased muscle tone

Question 6

What are the signs of ICP in children?

Answer 6

• Headache
• Vomiting
• Papilloedema and impaired upward gaze.

Question 7

What are the causes of raised ICP?

Answer 7

SOL
Hydrocephalus
Haematoma/haemorrhage

Question 8

What are the causes of hydrocephalus?

Answer 8

Obstruction:

• Congenital abnormalities
• Intraventricular haematoma
• Acquired aqueduct stenosis (following haemorrhage/inf)
• Increased CSF viscosity
• Increased CSF production
• Idiopathic raised intracranial pressure (more common in young obese women)

Question 9

How can you treat hydrocephalus?

Answer 9

Short term measure:
Hyperventilation of the patient can temporarily
decrease ICP by decreasing CO2 and causing vasoconstriction.

If idiopathic:
Special diuretics can be prescribed by a neurologist.

Surgical:
Ventriculoperitoneal shunt

Question 10

How can you treat raised ICP?

Answer 10

SOL: Remove if possible
Subdural haematoma: Drain
Hydrocephalus:
If idiopathic consider specialist diuretics
Ventriculoperitoneal shunt

Question 11

How do subdural haematomas tend to occur?

Answer 11

Blunt trauma:

• Shaking injury
• Sudden jerk forward in a RTA (road traffic accident)

Much more common in infants (elderly and alcoholics also)

Question 12

How do subdural haematomas present?

Answer 12

Acute:
Usually after a moderate to severe head injury. Lucid period for a few hours where the patient appears fine followed by a loss of consciousness as the haematoma forms.

Chronic:
2-3 weeks after the injury. Hx: of being off food nausea and vomiting. Progressive headache and gradual onset of focal neurology.