Subarachnoid hemorrhage

Background

Epidemiology

Of All pts in ED with c/o HA:

• 1% will have SAH
• 12% 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

(in order of relative risk)

1. Genetics (polycystic kidney disease, Ehler-Danlos, family hx)
2. Hypertension
3. Atherosclerosis
4. Cigarette smoking
5. Alcohol
6. Age > 85
7. Cocaine use
8. Estrogen deficiency

Clinical Manifestations

1. Sudden, severe headache (97% of cases)
   1. Sudden onset is more important finding than worst HA
2. May be associated with syncope, seizure, nausea/vomiting, and meningismus
   1. Meningismus may not develop until several hours after bleed (caused by blood breakdown > aseptic meningitis)
3. Retinal hemorrhages
   1. May be the only clue in comatose patients
4. Approximately 30-50% will have sentinel bleed/HA 6-20 days before SAH

Diagnosis

1. Non-Contrast Head CT
   1. 92% specific if performed w/in 24 hours of bleed
   2. ~100% sensitive if performed w/in 12 hours of bleed
   3. 91% sensitive in patients w/ normal neuro exam
      1. Decreases to ~50% sensitive by day 5
   4. Not as sensitive/specific for minor bleeds
   5. SAH 2/2 aneurysm (90%) - look in cisterns (especially suprasellar cistern)
   6. SAH 2/2 trauma - Look at convexities of frontal & temporal cortices
2. Lumbar Puncture
   1. Mandatory if there is a strong suspicion of SAH despite a normal head CT
   2. Findings:
      1. Elevated RBC count that doesn't decrease from tube one to four
         1. (Decreasing RBCs in later tubes can occur in SAH; only reliable if RBC count in final tube is nl)
      2. Opening pressure > 20 in 60% of patients with SAH
         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 2 hours after the bleed to develop (beware of false negatives)
         3. Sensitivity (93%) / specificity (95%) highest after 12 hours
   3. If unable to obtain CSF consider CTA

Treatment

1. Nimodipine
   1. Associated with improved neuro outcomes and decreased cerebral infarction
   2. Must be given 60mg q4hr PO or NGT only! (never IV)
2. 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 can try lowering sbp to < 140
      2. If pt is ALOC consider leaving BP alone, as the ALOC may be 2/2 reduced CPP
   2. If BP control is necessary, LABETALOL, ESMOLOL or NICARDIPINE is preferred
      1. Avoid vasodilators such as nitroprusside or NTG (increase cerebral blood volume --> increased ICP)
3. Discontinue/reverse all anticoagulation!
4. Seizure prophylaxis
   1. Controversial; some evidence suggests anti-epileptic drugs may worsen outcomes; 3 day course may be preferable
5. Glucocorticoid therapy
   1. Controversial; available 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. Avoid hypovolemia

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 initiated after the aneurysm has been treated (sx or intraluminal tx)
      1. Triple-H therapy (hemodilution + induced hypertension (pressors) + hypervolemia)
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, a flutter
   3. QT prolongation
   4. Deep, symmetric TWI
   5. Prominent U waves
4. Hydrocephalus
   1. Consider ventricular drain placement for deteriorating LOC + no improvement within 24 hours
5. Hyponatremia
   1. Usually due to SIADH
      1. Treat via isotonic, or if necessary, hypertonic saline (do not treat via water restriction!)

Grading (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 headache, stiff neck, no neurologic deficit except cranial nerve 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 dz, if dx missed pts return w/ higher grade (ie 3 or 4), 2/3 will be dead or vegetative at 6 mos if grade 3 or 4!

^Add one grade for serious sytemic dz (HTN, DM, severe stherosclerosis, COPD)

See Also

Neuro: Intracranial Hemorrhage

Source

7/09 PANI (Adapted from Lampe, Birnbaumer), UpToDate, EB Emergency Medicine, July 2009