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| ==Epidemiology==
| | ''Subarachnoid hemorrhage (SAH) is bleeding into the subarachnoid space. Clinical approach differs by etiology — see the appropriate page below:'' |
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| | *[[Aneurysmal subarachnoid hemorrhage]] — spontaneous/non-traumatic SAH (most commonly ruptured cerebral aneurysm) |
| | *[[Traumatic subarachnoid hemorrhage]] — SAH due to blunt or penetrating head trauma |
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| * Of All pts in ED with c/o HA:
| | [[Category:Neurology]] |
| * 1% will have SAH
| | [[Category:Critical Care]] |
| * 12% will have SAH if c/o worst HA of life
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| * 25% will have SAH if c/o worst HA of life + any neuro deficit
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| Risk Factors (in order of relative risk)
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| * Genetics (polycystic kidney disease, Ehler-Danlos, family hx)
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| * Hypertension
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| * Atherosclerosis
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| * Cigarette smoking
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| * Alcohol
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| * Age > 85
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| * Cocaine use
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| * Estrogen deficiency
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| == ==
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| ==Clinical Manifestations==
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| * Sudden, severe headache (97% of cases)
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| * Sudden onset is more important finding than worst HA
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| * May be associated with syncope, seizure, nausea/vomiting, and meningismus
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| * Meningismus may not develop until several hours after bleed (caused by blood breakdown > aseptic meningitis)
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| * Retinal hemorrhages
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| * May be the only clue in comatose patients
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| * Approximately 30-50% will have sentinel bleed/HA 6-20 days before SAH
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| == ==
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| ==Diagnosis==
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| * Non-Contrast Head CT
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| * 92% specific if performed w/in 24 hours of bleed
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| * ~100% sensitive if performed w/in 12 hours of bleed
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| * 91% sensitive in patients w/ normal neuro exam
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| * Decreases to ~50% sensitive by day 5
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| * Not as sensitive/specific for minor bleeds
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| * SAH 2/2 aneurysm (90%) - look in cisterns (especially suprasellar cistern)
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| * SAH 2/2 trauma - Look at convexities of frontal & temporal cortices
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| * Lumbar Puncture
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| * Mandatory if there is a strong suspicion of SAH despite a normal head CT
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| * Findings:
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| * Elevated RBC count that doesn't decrease from tube one to four
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| * (Decreasing RBCs in later tubes can occur in SAH; only reliable if RBC count in final tube is nl)
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| * Opening pressure > 20 in 60% of patients with SAH
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| * Can help differentiate from a traumatic tap (opening pressure expected to be normal)
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| * Elevated opening pressure also seen in cerebral venous thrombosis, IIH
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| * Xanthrochromia
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| * May help differentiate between SAH and a traumatic tap
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| * Takes at least 2 hours after the bleed to develop (beware of false negatives)
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| * Sensitivity (93%) / specificity (95%) highest after 12 hours
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| * If unable to obtain CSF consider CTA
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| ==Treatment ==
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| * Nimodipine
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| * Associated with improved neuro outcomes and decreased cerebral infarction
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| * Must be given 60mg q4hr PO or NGT only! (never IV)
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| * BP control
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| * No consensus on HTN (incr BP may maintain CPP but may also increase rate of bleeding)
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| * If pt is alert this means CPP is adequate so can try lowering sbp to < 140
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| * If pt is ALOC consider leaving BP alone, as the ALOC may be 2/2 reduced CPP
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| * If BP control is necessary, LABETALOL, ESMOLOL or NICARDIPINE is preferred
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| * Avoid vasodilators such as nitroprusside or NTG (increase cerebral blood volume --> increased ICP)
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| * Discontinue/reverse all anticoagulation!
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| * Seizure prophylaxis
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| * Controversial; some evidence suggests anti-epileptic drugs may worsen outcomes; 3 day course may be preferable
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| * Glucocorticoid therapy
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| * Controversial; available evidence suggests is neither beneficial nor harmful
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| * Glycemic control
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| * Controversial; consider sliding scale if long pt stay in ED while awaiting ICU bed
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| * Avoid hypovolemia
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| ==Complications==
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| * Rebleeding
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| * Risk is highest within first 24 hours (2.5-4%), particularly within first 6 hours
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| * Usually diagnosed by CT after acute deterioration in neuro status
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| * Only aneurysm treatment is effective in preventing rebleeding
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| * Vasospasm
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| * Leading cause of death and disability after rupture
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| * Typically begins no earlier than day three after hemorrhage
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| * Characterized by decline in neuro status
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| * Aggressive treatment can only be initiated after the aneurysm has been treated (sx or intraluminal tx)
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| * Triple-H therapy (hemodilution + induced hypertension (pressors) + hypervolemia)
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| * Cardiac abnormalities (?2/2 release of catecholamines due to hypoperfusion of hypothalamus)
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| * Ischemia
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| * Elevated troponin (20-40% of cases)
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| * ST segment depression
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| * Rhythm disturbances
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| * Torsades, a fib, a flutter
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| * QT prolongation
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| * Deep, symmetric TWI
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| * Prominent U waves
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| * Hydrocephalus
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| * Consider ventricular drain placement for deteriorating LOC + no improvement within 24 hours
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| * Hyponatremia
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| * Usually due to SIADH
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| * Treat via isotonic, or if necessary, hypertonic saline (do not treat via water restriction!)
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| ==Grading==
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| Hunt and Hess
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| Grade 0: Unruptured aneurysm
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| Grade 1: Asymptomatic or mild HA and slight nuchal rigidity
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| Grade 1a: No acute meningeal/brain reaction, with fixed neurological def
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| Grade 2: Moderate to severe headache, stiff neck, no neurologic deficit except cranial nerve palsy
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| Grade 3: Mild mental status change (drowsy or confused), mild focal neurologic deficit
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| Grade 4: Stupor or moderate to severe hemiparesis
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| Grade 5: Coma or decerebrate rigidity
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| *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!
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| *Add one grade for serious sytemic dz (HTN, DM, severe stherosclerosis, COPD)
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| == ==
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| ==See Also==
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| Neuro: Intracranial Hemorrhage
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| == ==
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| ==Source==
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| 7/09 PANI (Adapted from Lampe, Birnbaumer), UpToDate, EB Emergency Medicine, July 2009
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| [[Category:Neuro]] | |
