Subarachnoid hemorrhage - NYSORA

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Subarachnoid hemorrhage

Learning objectives

  • Describe the pathophysiology and symptoms of a subarachnoid hemorrhage
  • Diagnose and clinically grade a subarachnoid hemorrhage
  • Manage patients presenting with a subarachnoid hemorrhage


  • Subarachnoid hemorrhage account for 5% of all strokes
  • Mortality rate ~50%
  • One-third of survivors need lifelong care
  • Prompt diagnosis and early treatment are critical


  • Etiology
    • Intracranial aneurysm (85% of cases)
    • Arteriovenous malformations
    • Trauma
    • Moyamoya disease
  • Risk factors
    • Hypertension
    • Atherosclerosis
    • Cocaine use
    • Alcohol abuse
    • Smoking
    • Connective tissue disorders
    • Coarctation of the aorta
    • Congenital conditions (autosomal-dominant polycystic kidney disease, Ehlers Danlos Type 4, familial intracerebral aneurysms)
  • Cause
    • Hemodynamically induced shear stress (sudden increase in cerebrovascular arterial pressure)
  • Aneurysmal rupture leads to blood quickly traversing through the intracranial cisterns and subarachnoid space (within seconds)
  • Global cerebral ischemia resulting from increased intracranial pressure, decreased cerebral perfusion, and reduced cerebral blood flow
  • Intraventricular bleeding can cause acute ventricular dilatation and hydrocephalus
  • Brain tissue oxygen pressure and pH are reduced
  • Compensatory hypertension occurs within minutes to hours
  • Blood-brain barrier disruption, cerebral edema, and a thromboinflammatory cascade

Signs & symptoms

  • Sudden onset of “worst headache of life”
  • Loss of consciousness
  • Nausea and/or vomiting
  • Nuchal rigidity
  • Photophobia
  • Seizures
  • Comatose and hypertensive at presentation


  • Non-contrast cranial CT 
  • Lumbar puncture in patients with a high index of suspicion and a normal CT scan (red blood cell count, bilirubin level, and xanthochromia)
  • CT angiogram and/or digital subtraction angiography to identify the cause

Clinical grading

GradeWorld Federation of Neurologic SurgeonsHess and HuntFisher (CT scan appearance)
1Glasgow Coma Scale score 15, no motor deficitAsymptomatic or minimal headache and slight nuchal rigidityNo blood detected
2Glasgow Coma Scale score 13-14, no motor deficitModerate to severe headache nuchal rigidity, no neurological deficit other than cranial nerve palsyDiffuse thin layer of subarachnoid blood (vertical layers <1 mm thick)
3Glasgow Coma Scale score 13-14 with motor deficitDrowsy, confusion, or mild neurological deficitLocalized clot or thick layer of subarachnoid blood (vertical layers ≥1 mm thick)
4Glasgow Coma Scale score 7-12, with or without motor deficitStupor, moderate-to-severe hemiparesis, possibly early decerebrate rigidity and vegetative disturbancesIntracerebral or intraventricular blood with diffuse or no subarachnoid blood
5Glasgow Coma Scale score 3-6, with or withour motor deficitDeep coma, decerebrate rigidity, moribund appearance



  • Acute management

Subarachnoid hemorrhage, oxygenation, ventilation, airway, intubation, cerebral perfusion, external ventricular drain, cerebrospinal fluid, hypertension, analgesics, anxiolysis, blood pressure, nicardipine, esmolol, clevidipine, antigoagulants, antifibrinolytics, seizure prophylaxis, nimodipine, nasogastric tube, hypotension

  • Treatment options
    • Endovascular coiling: Preferred in geriatric patients, particularly those with high-grade aneurysmal subarachnoid hemorrhage from the rupture of basilar apex aneurysm
    • Surgical clipping: Preferred in patients with large intraparenchymal hematomas, aneurysm of the middle cerebral artery, and in those not likely to be compliant with long-term follow-up
  • Anesthetic management

subarachnoid hemorrhage, pulmonary, cardiovascular, neurologic, endocrine, re-bleeding, cerebral perfusion, brain swelling, neurophysiological monitoring, glycemia, rapid sequence induction, succinylcholine, vasopressor, hypocarbia, hypercarbia, arterial line, ecg, intracranial pressure, cerebral perfusion, external ventricular drain, jugular venous oximetry, electroencephalogram, somatosensory-evoked potentials, motor-evoked potentials, isoflurane, desflurane, sevoflurane, acidosis, hyperventilation, nitrous oxide, dexmedetomidine, ketamine, hypertension

subarachnoid hemorrhage, intracranial pressure, brain relaxation, positioning, normocarbia, hypocarbia, mannitol, hypertonic saline, flurosemide, cerebrospinal fluid drainage, burst suppression, propofol, tiopental, hyperventilation, temporary clipping, ischemia, metabolic demand, hypothermia, hypertension, adenosine-induced temporary flow arrest, coronary artery disease, cardiac conduction abnormalities, reactive airways disease, rapid ventricular pacing, tachycardia, bipolar pacing electrode, internal jugular vein, right ventricle, external defibrillation pads, cardiac arrhythmias, vasospasm, delayed cerebral ischemia, hypovolemia, vasopressors, inotropes, nimodipine, extubate, lidocaine, esmolol, labetalol, systemic blood pressure

Suggested reading

  • Deepak Sharma; Perioperative Management of Aneurysmal Subarachnoid Hemorrhage: A Narrative Review. Anesthesiology 2020; 133:1283–1305
  • Kundra S, Mahendru V, Gupta V, Choudhary AK. Principles of neuroanesthesia in aneurysmal subarachnoid hemorrhage. J Anaesthesiol Clin Pharmacol. 2014;30(3):328-337.
  • Luoma A, Reddy U. Acute management of aneurysmal subarachnoid haemorrhage. Continuing Education in Anaesthesia Critical Care & Pain. 2013;13(2):52-8.

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