Raised Intracranial Pressure

Normal ICP range is < 15mm/Hg. Causes of a raised ICP include:

• Brain tumours – Primary or Metastatic

  • Most common cancers to metastasise to the brain – Lung, Breast, Renal, Melanoma

• Intracranial HTN

• Haemorrhage

• Infection – Meningitis, Encephalitis, Brain abscess

• Hydrocephalus

• Cerebral oedema

• Fluid outflow obstruction – Rare causes include Chiari malformation, Vasculitis, Craniosynostosis (abnormal skull growth)

Presentation

• Headache – Persistent, Worse in morning/on coughing/leaning forward/straining

• Papilloedema

• Vomiting

• Pupil changes – first constriction, dilation later

• Altered GCS - drowsiness, listlessness, irritability

• Peripheral visual field loss

Very late, and worrying, sign here is Cushing's response, which is seen by as the brain herniates down into the foramen magnum, resulting in a fall in HR + rise in BP (opposite signs of shock).

Investigation

• Bloods - F&E, FBC, LFT, Glucose, Serum osmolality, Clotting

• Blood culture

• Consider toxicology screen

• CXR – Any source of infection indicating abscess

• CT Head - New onset headache and focal neurological symptoms indicates this should be done urgently

• Consider LP if safe - Could disrupt the ICP, therefore dramatically increasing the risk of herniation/coning and cushing's response

Management

The aims here are to:

• Raise MAP to maintain cerebral perfusion

• Lower ICP

• Treat the underlying cause

Patients given Hypertonic Saline to draw fluid back into vessels. This is better than Mannitol in the short-term reduction of ICP.

Other things that may be done include:

• If intubated, Hyperventilate the patient – This will decrease pCO2, therefore causing cerebral vasoconstriction and reducing ICP very quickly

• Barbiturate coma – Used only in refractory cases