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| == Background ==
| | ''Subarachnoid hemorrhage (SAH) is bleeding into the subarachnoid space. Clinical approach differs by etiology — see the appropriate page below:'' |
| === Pearls ===
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| #Obtain GCS before intubation
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| #If intubate prevent hypertension (rebleeding)
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| ##Pretreatment
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| ###Lidocaine 1-1.5mg/kg (100mg) (blunts incr in BP)
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| ###Fentanyl 200mcg (sympatholytic)
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| ##Sedation
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| ###If pt has high BP - use propofol
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| ###If pt has adequate BP - use etomidate
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| #Treat pain
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| ##Prevents incr catacholamines/ incr BP
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| === Epidemiology ===
| | *[[Aneurysmal subarachnoid hemorrhage]] — spontaneous/non-traumatic SAH (most commonly ruptured cerebral aneurysm) |
| *Of All pts in ED who p/w HA: | | *[[Traumatic subarachnoid hemorrhage]] — SAH due to blunt or penetrating head trauma |
| **1% will have SAH
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| **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
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| === Risk Factors ===
| | [[Category:Neurology]] |
| #Genetics (polycystic kidney disease, Ehler-Danlos, family hx)
| | [[Category:Critical Care]] |
| #Hypertension
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| #Atherosclerosis
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| #Cigarette smoking
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| #Alcohol
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| #Age >50
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| #Cocaine use
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| #Estrogen deficiency
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| | |
| === Etiology of Spontaneous SAH ===
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| #Ruptured aneurysm (85%)
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| #Nonaneurysmal (15%)
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| ##Perimesencephalic hemorrhage (10%)
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| ##Other
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| ###Tumor, coagulopathy, dissection, vasculitis, sickle cell, venous sinus thrombosis
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| | |
| ==Clinical Features==
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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 hrs after bleed (blood breakdown -> aseptic meningitis)
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| #Retinal hemorrhage
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| ##May be the only clue in comatose patients
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| #30-50% will have sentinel bleed/HA 6-20d before SAH
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| == Diagnosis ==
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| '''If concerned for SAH and CT normal must perform LP'''
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| #Non-Contrast Head CT
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| ##90%-98% sensitive if performed w/in 24 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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| ##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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| ##Give 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 consider lowering sbp to 120-140
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| ####If pt has history of HTN consider lowering sbp to ~160
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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 use NICARDIPINE, LABETALOL, or ESMOLOL
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| ###Avoid vasodilators such as nitroprusside or NTG (increase cerebral blood volume > increased ICP)
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| ##Avoid hypotension
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| ###Maintain MAP > 80
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| ####Give IVF
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| ####Give pressors if IVF ineffective
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| #Discontinue/reverse all anticoagulation
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| ##Coumadin - give (prothrombin complex conc or FFP) and vit K)
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| ##Aspirin - give DDAVP
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| ##Plavix - give platelets
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| #Seizure prophylaxis
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| ##Controversial; 3 day course may be preferable
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| ##Phenytoin load
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| #Glucocorticoid therapy
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| ##Controversial; 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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| #Keep head of bed elevated
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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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| == Prognosis ==
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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 systemic dz (HTN, DM, severe atherosclerosis, COPD)
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| === World Federation of Neurosurgical Societies (WFNS) ===
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| {| cellspacing="1" cellpadding="1" border="1" width="200"
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| |-
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| | '''Grade'''<br>
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| | '''GCS'''<br>
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| | '''Major Focal Deficit'''<br>
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| |-
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| | 0 (unruptured)<br>
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| | NA<br>
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| | NA<br>
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| |-
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| | 1<br>
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| | 15<br>
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| | Absent<br>
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| |-
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| | 2<br>
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| | 13-14<br>
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| | Absent<br>
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| |-
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| | 3<br>
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| | 13-14<br>
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| | Present<br>
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| |-
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| | 4<br>
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| | 7-12<br>
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| | Present/absent<br>
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| |-
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| | 5<br>
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| | 3-6<br>
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| | Present/absent<br>
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| |}
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| <br>
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| == See Also ==
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| [[Intracranial Hemorrhage]] | |
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| == Source ==
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| UpToDate
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| EB Emergency Medicine, July 2009
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| EMCrit Podcast 8
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| [[Category:Neuro]] | |
