Raised Intracranial Pressure

As the brain and ventricles are enclosed by a rigid skull, they have a limited ability to accommodate additional volume. Additional volume (e.g. haematoma, tumour, excessive CSF) will therefore lead to a rise in intracranial pressure (ICP).

Pathophysiology

• the normal ICP is 7-15 mmHg in adults in the supine position
• cerebral perfusion pressure (CPP) is the net pressure gradient causing cerebral blood flow to the brain
• CPP = mean arterial pressure - ICP

Causes

• idiopathic intracranial hypertension
• traumatic head injuries
• infection
  • meningitis
• tumours
• hydrocephalus

Features

• headache
• vomiting
• reduced levels of consciousness
• papilloedema
• Cushing's triad
  • widening pulse pressure
  • bradycardia
  • irregular breathing