Subarachnoid hemorrhage

Definition

• Life-threatening intracerebral hemorrhage occurring below the arachnoid membrane

Epidemiology

• Incidence of 10-14 per 100,000 persons / year
  • Accounts for 3-5% of all strokes
• More common in women
• About 1% of population has an asymptomatic intracranial aneurysm

WFNS Grade (Clinical)

• I -- GCS 15, no motor deficit
• II -- GCS 13-14, no motor deficit
• III -- GCS 13-14, motor deficit
• IV -- GCS 7-12 +/- motor deficit
• V -- GCS 3-6, motor deficit present or absent

Fisher Grade (Radiological)

• I -- no blood
• II -- diffuse deposition of SAH without clots or layers of blood >1mm
• III -- localized clots and/or vertical layers of blood 1mm or > thickness
• IV -- diffuse or no subarachnoid blood but intracerebral or intraventricular clots

Etiology

• Trauma (most common)
• Intracranial aneurysms (80% of spontaneous SAH)
  • AComm most common
  • PComm second-most common
• Non-aneurysmal perimesencephalic hemorrhage
• Arteriovenous malformations
• Arterial dissection and CNS vasculitis
• Coagulopathies
• Drug-induced
  • Cocaines
  • Amphetamines
• Pituitary apoplexy

Locations

• Basal ganglia and thalamus are more likely to be hypertension-related
• Cerbellum
• Lobar is more likely to be amyloid
• Pontine

Risk factors

• Smoking (RR 10-20)
• Hypertension and alcohol abuse
• Family history of polycystic kidney disease or connective tissue disorders

Screening

• Generally not recommended unless strong family history
• Treat if >10mm

Clinical Manifestations

• "Thunderclap headache"/"worst headache of my life"
  • Peaks in minutes
  • May have occurred with exertion (50%) or in sleep (15-30%)
• Soon after onset
  • +/- nausea & vomiting
  • +/- transient loss of consciousness or weakness
• Sentinel bleed with warning headache in 20-50%
• May present with seizures
• Other signs
• Reduced of altered level of consciousness (30%)
• Intraocular hemorrhage (20-40%)
  • Presence of subhyaloid hemorrhage pathognomonic
• Cranial nerve palsies
  • Especially oculomotor (PComm aneurysm)
• Meningismus, after a few hours (from blood breakdown)
• Focal deficits
  • Hemiparesis possible if intracerebral clot (e.g. MCA)
• Systemic features
  • Fever, hypertension, arrhythmias/EKG changes
• Paramesencephalic subarachnoid hemorrhage
  • More benign, small aneurysm that self-resolves
  • Two negative angiograms separated by 10-14 days

Investigations

• CT head
• +/- lumbar puncture

Management

• Initial management
  • Stabilize patient (ABCs)
  • Send for CT head +/- LP to confirm diagnosis
  • Consult neurosurgery
• Stabilization
  • Ensure IV access
  • Manage airway, with intubation if necessary
  • Cardiac monitoring (arrhythmias are common)
  • Bed rest, elevate head of bed to 30 degrees
  • Pneumatic compression devices for thromboembolism prophylaxis
  • Adequate fluid intake
  • Blood pressure control
    • Goal: SBP <160 (now <140) or less and MAP <110
    • Be aggressive, using IV labetalol, hydralazine, enalapril
• Vasospasm prophylaxis: nimodipine 60mg po q4h for 21 days
• Treat coagulopathies
• After transfer to tertiary centre
  • Serial CT or CT angiogram
  • Angiogram when available
  • Surgical clipping or endovascular coiling by neurosurgery or interventional radiology

Complications

• Vasospasm
  • Onset at 3-5 days, peak at 1-2 weeks
  • Evaluate with transcranial dopplers +/- angiogram, although clinical diagnosis more important that radiological
  • Prophylaxis with nimodipine
  • Hyperdynamic therapy (3H)
    • Hyperhydration (150-200cc/h)
    • Hypertension (inotropes if necessary)
    • Hemodilution
    • Only after aneurysm is secure
• Hydrocephalus
  • May need VP shunt
• EKG changes
  • Changes to ST, T, and U
  • Prolonged QT (60%)
  • Arrhythmias
• Rebleeding
  • 50% re-reupture within 6 months
  • About 2%/day up to 15-20% at 14 days
  • Often fatal
• Seizures
  • Can prophylax with phenytoin for 1 week
• Hyponatrmia
  • SIADH or cerebral salt wasting (atrial natriuretic protein), depending on volume status
  • Avoid hypotonic fluids

Prognosis

• 10% died before hospital, usually from arrhythmias or acute hydrocephalus
• 10% die in first 24h, usually from early rebleeding
• Long-term survival less than 50%
  • 1/2 will never return to previous quality of life