Raised intracranial pressure

• How can raised ICP occur?


  Skull has a fixed volume

  So, expansion of the brain, CSF or blood within skull can only be compensated for minimally before ICP begins to rise rapidly

  (Can slightly compensate in infants when fontanelles are still present)
• What can cause raised ICP?


  Space occupying lesions (benign/malignant -> cerebral abscesses, vascular lesions & tuberculomas)

  Haemorrhage -> can be extradural, subdural or intracerebral

  Cerebral oedema -> can be secondary to trauma, infarction or reactive (e.g. around a malignant deposit)

  Hydrocephalus

  Inflammation

  Idiopathic intracranial HTN -> raised ICP w/o clear cause

  Cerebral venous thrombosis
• What are the signs & symptoms of raised ICP?


  Headache (often worse on waking, lying down or when coughing/straining)

  Nausea & vomiting

  Altered mental state (lethargy or irritability)

  Diplopia -> due to cranial nerve palsies

  Seizures

  Cushing's reflex (HTN, bradycardia & irregular breathing)

  Cranial nerve palsies (esp. oculomotor (CN III) & abducens (CN VI))

  Decreased consciousness

  Focal neurological signs (hemiparesis)

  Fundoscopy -> blurring of disc margins, loss of venous pulsations, retinal haemorrhages
• ADD WHAT ARE THE SIGNS OF CONING
• What are the Inx for raised ICP?


  Obs

  Full Hx & examination

  Blood glucose

  Blood cultures?

  CT head (diagnostic of raised ICP)
• What is the management of raised ICP?


  Depends on underlying cause

  General principles

  • elevate head of bed to 30 degrees
  • pts with seizures or reduced consciousness -> intubation & ventilation
  • ICP monitoring
  • CSF drainage
  • manage seizures
  • analgesia, sedation, antiemetics
  • IV mannitol or hypertonic saline
  • in intubated pts, hyperventilation may be used to lower CO2 levels -> reduced ICP
  • surgery (depressive craniectomy)
• What are the possible complications of raised ICP?


  Coma

  Death

  Status epilepticus

  Permanent neurological deficits

  Tonsillar herniation ('coning')
• What are the signs & symptoms of coning?

  Neck stiffness

  Head tilt

  Bradycardia & HTN & irregular breathing (Cushing's law)