Subarachnoid hemorrhage

Background

Pearls

1. Obtain GCS before intubation
2. If intubate prevent HTN (rebleeding)
   1. Pretreatment
      1. Lidocaine 1-1.5mg/kg (100mg) (blunts incr in BP)
      2. Fentanyl 200mcg (sympatholytic)
   2. Sedation
      1. If pt has high BP - use propofol
      2. If pt has adequate BP - use etomidate
   3. Treat pain
      1. Prevents incr catacholamines / incr BP

Epidemiology

• Of All pts in ED who p/w HA:
  • 1% will have SAH
  • 10% will have SAH if c/o worst HA of life
  • 25% will have SAH if c/o worst HA of life + any neuro deficit

Risk Factors

1. Genetics (polycystic kidney disease, Ehler-Danlos, family hx)
2. Hypertension
3. Atherosclerosis
4. Cigarette smoking
5. Alcohol
6. Age >50
7. Cocaine use
8. Estrogen deficiency

Etiology of Spontaneous SAH

1. Ruptured aneurysm (85%)
2. Nonaneurysmal (15%)
   1. Perimesencephalic hemorrhage (10%)
   2. Other: tumor, coagulopathy, dissection, vasculitis, SCD, venous sinus thrombosis

Clinical Features

1. Sudden, severe headache that reaches maximal intensity within minutes (97% of cases)
   1. Sudden onset is more important finding than worst HA
2. May be a/w syncope, seizure, nausea/vomiting, meningismus
   1. Meningismus may not develop until hrs after bleed (blood breakdown -> aseptic meningitis)
3. Retinal hemorrhage
   1. May be the only clue in comatose patients
4. Sentinel bleed/HA 6-20d before SAH (30-50% of pts)

DDX

1. Other intracranial hemorrhage
2. Drug toxicity
3. Ischemic stroke
4. Meningitis
5. Encephalitis
6. Intracranial tumor
7. Intracranial hypotension
8. Metabolic derangements
9. Venous thrombosis
10. Primary headache syndromes (benign thunderclap headache, migraine, cluster headache)

Diagnosis

If concerned for SAH and CT normal strongly consider LP

1. Non-Contrast Head CT
   1. Sensitivity
      1. Within 12hr of onset of symptoms: 98% Sn
      2. Within 24hr of onset of symptoms: 93% Sn
      3. Within 5d of onset of symptoms: 50% Sn
      4. Not as sensitive/specific for minor bleeds
   2. Findings
      1. SAH due to aneurysm - look in cisterns (esp. suprasellar cistern)
      2. SAH due to trauma - look at convexities of frontal and temporal cortices
2. Lumbar Puncture
   1. Findings:
      1. Elevated RBC count that doesn't decrease from tube one to four
         1. Note: decreasing RBCs in later tubes can occur in SAH; only reliable if RBC count in final tube is nl
      2. Opening pressure >20 (60% of pts)
         1. Can help differentiate from a traumatic tap (opening pressure expected to be normal)
         2. Elevated opening pressure also seen in cerebral venous thrombosis, IIH
      3. Xanthrochromia
         1. May help differentiate between SAH and a traumatic tap
         2. Takes at least 2hr after bleed to develop (beware of false negative if measure early)
         3. Sn (93%) / Sp (95%) highest after 12hr
   2. If unable to obtain CSF consider CTA
      1. CTA also highly sensitive for predicting delayed cerebral ischemia

Treatment

Physiologic derangements, such as hypoxemia, metabolic acidosis, hyperglycemia, BP instability, and fever, can worsen brain injury and has been independently associated with increased M&M, but no studies showing benefit of corrections.

1. BP control
   1. No consensus on HTN (incr BP may maintain CPP but may also increase rate of bleeding)
      1. If pt is alert this means CPP is adequate so consider lowering SBP to 120-140
         1. If pt has history of HTN consider lowering SBP to ~160
      2. If pt is ALOC consider leaving BP alone as the ALOC may be 2/2 reduced CPP
   2. If BP control is necessary use nicardipine, labetalol, or esmolol
      1. Avoid vasodilators such as nitroprusside or NTG (incr cerebral blood volume -> incr ICP)
   3. Avoid hypotension
      1. Maintain MAP >80
         1. Give IVF
         2. Give pressors if IVF ineffective
2. Discontinue/reverse all anticoagulation
   1. Coumadin - (Prothrombin complex conc or FFP) + vit K
   2. Aspirin - DDAVP
   3. Plavix - Platelets
3. Nimodipine
   1. Prevents vasospasm (a/w improved neuro outcomes and decreased cerebral infarction)
   2. Give 60mg q4hr PO or NGT only (never IV) within 96hr of symptom onset. NNT 13 to prevent one poor outcome
   3. Keep an eye on BP for fluctuations
4. Seizure prophylaxis
   1. Controversial; 3 day course may be preferable
   2. Keppra preferred. Phenytoin a/w worse neurologic & cognitive outcome
5. Glucocorticoid therapy
   1. Controversial; evidence suggests is neither beneficial nor harmful
6. Glycemic control
   1. Controversial; consider sliding scale if long pt stay in ED while awaiting ICU bed
7. Keep head of bed elevated
8. Aneurysm Tx
   1. Surgical clipping and endovascular coiling are definitive tx
   2. Antifibrinolytic - Controversial; if delayed aneurysmal tx, consider short term therapy (<72 hrs) with TXA or aminocaproic acid

Complications

1. Rebleeding
   1. Risk is highest within first 24 hours (2.5-4%), particularly within first 6 hours
   2. Usually diagnosed by CT after acute deterioration in neuro status
   3. Only aneurysm treatment is effective in preventing rebleeding
2. Vasospasm
   1. Leading cause of death and disability after rupture
   2. Typically begins no earlier than day three after hemorrhage
   3. Characterized by decline in neuro status
   4. Aggressive treatment can only be started after aneurysm has been treated (surgery or intraluminal tx)
      1. Tx for symptomatic vasospasm: Triple-H therapy (hemodilution + induced hypertension (pressors) + hypervolemia), ballon angioplasty, or intra-arterial vasodilators.
         1. Studies have not provided strong evidence of benefit Triple-H therapy
3. Cardiac abnormalities (?2/2 release of catecholamines due to hypoperfusion of hypothalamus)
   1. Ischemia
      1. Elevated troponin (20-40% of cases)
      2. ST segment depression
   2. Rhythm disturbances
      1. Torsades, A-fib/flutter
   3. QT prolongation
   4. Deep, symmetric TWI
   5. Prominent U waves
4. Hydrocephalus
   1. Consider ventricular drain placement for deteriorating LOC + no improvement w/in 24hr
5. Hyponatremia
   1. Usually due to SIADH
      1. Treat via isotonic, or if necessary, hypertonic saline (do not treat via H2O restriction)
   2. Rarely due to cerebral salt-wasting
      1. Volume depleted, so treat with isotonic saline

Prognosis

Hunt and Hess

• Grade 0: Unruptured aneurysm
• Grade 1: Asymptomatic or mild HA and slight nuchal rigidity
  • Grade 1a: No acute meningeal/brain reaction, with fixed neurological def
• Grade 2: Moderate to severe HA, stiff neck, no neurologic deficit except CN palsy
• Grade 3: Mild mental status change (drowsy or confused), mild focal neurologic deficit
• Grade 4: Stupor or moderate to severe hemiparesis
• Grade 5: Coma or decerebrate rigidity

• Grade 1 or 2 have curable disease
• Add one grade for serious systemic disease (HTN, DM, severe atherosclerosis, COPD)

World Federation of Neurosurgical Societies (WFNS)

• Grade 1: GCS of 15, no motor deficits
• Grade 2: GCS of 13 or 14, no motor deficits
• Grade 3: GCS of 13 or 14, with motor deficits
• Grade 4: GCS of 7–12, with or without motor deficits
• Grade 5: GCS of 3–6, with or without motor deficits

First-degree relatives are at 2-5 fold increase in SAH, so screening is possibility.

See Also

• Intracranial Hemorrhage (Main)
• Head Trauma

Source

• UpToDate
• EB Emergency Medicine, July 2009
• EMCrit Podcast 8
• Tintinalli
• www.epmonthly.com/features/current-features/lp-for-subarachnoid-hemorrhage-the-700-club