Raised Intracranial Pressure

Question 1

Clinical Features of Raised Intracranial Pressure.

Answer 1

1. Headache.
2. Vomiting.
3. Altered Mental State.
4. Visual Field Defects.
5. Seizures - Focal.
6. Unilateral Ptosis.
7. CN III/XI Palsy.
8. Cushing’s Triad.

Question 2

Key Features of the Headache (4).

Answer 2

1. Constant.
2. Nocturnal.
3. Worse on Waking.
4. Worse on Coughing, Straining, Bending Forward.

Question 3

What is Cushing’s Reflex?

Answer 3

1. Hypertension (Widening Pulse Pressure).
2. Bradycardia.
3. Cheyne-Stokes Respiration (Abnormal Breathing).

Question 4

Differential Diagnosis of Raised Intracranial Pressure (6).

Answer 4

1. Brain Tumours.
2. Intracranial Haemorrhage.
3. Idiopathic Intracranial Hypertension.
4. Abscesses or Infection.
5. Hydrocephalus.
6. Traumatic Head Injuries.

Question 5

Pathophysiology of Raised Intracranial Pressure (3).

Answer 5

1. Normal : 7-15 mmHg in Supine Position.
2. CPP - Cerebral Perfusion Pressure (net pressure gradient causing cerebral blood flow to the brain.
3. CPP = Mean Arterial Pressure - ICP.

Question 6

Fundoscopy Changes of Raised Intracranial Pressure (7).

Answer 6

1. Papilloedema (Swelling of the Optic Disc).
2. Blurring of Optic Disc Margin.
3. Elevated Optic Disc (Retinal Vessels Curve Over Raised Disc).
4. Loss of Venous Pulsation.
5. Engorged Retinal Veins.
6. Haemorrhages Around Optic Disc.
7. Paton’s Lines (Creases in the Retina Around Optic Disc).

Question 7

Pathophysiology of Raised Intracranial Pressure (4).

Answer 7

1, Optic Sheath is connected to SAH space.

2. CSF under High Pressure flows into the Optic Nerve Sheatth.
3. Pressure Around Optic Nerve Increases.
4. Optic Disc Swelling.

Question 8

Investigations of Raised Intracranial Pressure (2).

Answer 8

1. Underlying Cause : Neuroimaging (CT/MRI).

2. Invasive ICP Monitoring.

Question 9

What is Invasive ICP Monitoring? (3)

Answer 9

1. Catheter into Lateral Ventricles of Brain.
2. Collect CSF Samples and Drain Small Amounts (Diagnostic and Therapeutic).
3. Cut-Off of >20mmHg = Determines Treatment.

Question 10

Management of Raised Intracranial Pressure (5).

Answer 10

1. Treat Underlying Cause.
2. Elevate Head to 30 Degrees.
3. IV Mannitol - Osmotic Diuretic.
4. Controlled Hyperventilation.
5. Removal of CSF.

Question 11

What is Controlled Hyperventilation? (3)

Answer 11

1. Reduce pCO2 - vasoconstriction of cerebral arteries - reduce ICP.
2. Rapid temporary lowering of ICP.
3. Caution : Reduce blood flow to already ischaemic parts of the brain.

Question 12

How can CSF be removed? (3)

Answer 12

1. Drain from ICP Monitoring.
2. Repeated Lumbar Puncture (e.g. IIH).
3. Ventriculoperitoneal Shunt (e.g. Hydrocephalus).