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Subarachnoid haemorrhage

Background knowledge 🧠

Definition

  • Subarachnoid haemorrhage (SAH) is bleeding into the subarachnoid space.
  • Usually caused by rupture of a cerebral aneurysm.
  • Leads to increased intracranial pressure and potential brain damage.

Epidemiology

  • Incidence: approximately 6-10 per 100,000 people per year.
  • More common in women and in older adults.
  • High morbidity and mortality rate.
  • Significant risk factors: hypertension, smoking, family historyΒ of aneurysms.

Aetiology and Pathophysiology

  • Rupture of saccular (berry) aneurysms (most common).
  • Arteriovenous malformations (AVMs).
  • Trauma.
  • Extension of intracerebral haemorrhage.
  • Idiopathic (in some cases).
  • Pathophysiology: Blood in subarachnoid space leads to irritation of meninges and increased intracranial pressure.

Clinical Features 🌑️

Symptoms

  • Sudden onset of severe headache (thunderclap headache).
  • Nausea and vomiting.
  • Photophobia.
  • Neck stiffness
  • Loss of consciousness (in severe cases).
  • Focal neurological deficits.

Signs

  • Meningism (neck stiffness, positive Brudzinski and Kernig signs).
  • Papilloedema.
  • Retinal haemorrhages.
  • Cranial nerve palsies.
  • Decreased level of consciousness.
  • Hemiparesis (if large haemorrhage).

Investigations πŸ§ͺ

Tests

  • CT head (first-line).
  • Lumbar puncture for xanthochromia (if CT negative but suspicion remains).
  • MRI/MRA (for further assessment).
  • CT angiography (to locate aneurysm).
  • Digital subtraction angiography (gold standard for aneurysm detection).
  • Blood tests: full blood count, clotting profile, electrolytes.

Management πŸ₯Ό

Management

  • Resuscitation and stabilisation (ABCDE approach).
  • Early neurosurgical consultation.
  • Nimodipine to prevent vasospasm.
  • Endovascular coiling or surgical clipping of aneurysm.
  • Management of complications (e.g., hydrocephalus, rebleeding).
  • Supportive care: pain management, antiemetics, stool softeners.
  • Intensive monitoring (ICU if necessary).

Complications

  • Rebleeding.
  • Vasospasm and delayed cerebral ischaemia.
  • Hydrocephalus.
  • Hyponatraemia (SIADH).
  • Seizures.
  • Cognitive and functional deficits.
  • Death (if severe or untreated).

Prognosis

  • Mortality rate: approximately 30-40%.
  • Poor outcomes associated with delayed diagnosis and treatment.
  • Better prognosis with early intervention and effective management.
  • Rehabilitation is crucial for recovery.
  • Regular follow-up required to monitor for complications.

Key Points

  • Early recognition and treatment are essential.
  • High index of suspicion in patients with sudden severe headache.
  • Multidisciplinary approach improves outcomes.
  • Regular monitoring and prevention of complications are key.

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