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| == Background ==
| | ''Subarachnoid hemorrhage (SAH) is bleeding into the subarachnoid space. Clinical approach differs by etiology — see the appropriate page below:'' |
| *Abreviation: SAH
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| === Pearls ===
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| *Obtain GCS before intubation | | *[[Aneurysmal subarachnoid hemorrhage]] — spontaneous/non-traumatic SAH (most commonly ruptured cerebral aneurysm) |
| *If intubate prevent HTN (rebleeding)
| | *[[Traumatic subarachnoid hemorrhage]] — SAH due to blunt or penetrating head trauma |
| **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 | |
| ***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 ===
| | [[Category:Neurology]] |
| | | [[Category:Critical Care]] |
| *Of All pts in ED who p/w HA:
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| **1% will have SAH
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| **10% 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 ===
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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 >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%) - lower risk of complications
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| **Other: tumor, coagulopathy, dissection, vasculitis, SCD, venous sinus thrombosis
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| == Clinical Features ==
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| *Sudden, severe [[headache]] that reaches maximal intensity within minutes (97% of cases)
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| **Sudden onset is more important finding than worst [[headache]]
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| *May be associated with [[syncope]], [[seizure]], [[nausea/vomiting]], meningismus
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| **Meningismus may not develop until 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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| *There is a sentinel bleed headache 6-20 days before serious SAH in 30-50% of patients
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| == Differential Diagnosis ==
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| {{Intracranial hemorrhage DDX}}
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| ===Other===
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| *Drug toxicity
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| *Ischemic [[Stroke (Main)|Stroke]]
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| *[[Meningitis]]
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| *[[Encephalitis]]
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| *Intracranial tumor
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| *Intracranial hypotension
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| *Metabolic derangements
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| *[[Cerebral venous thrombosis]]
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| *Primary headache syndromes (benign thunderclap headache, [[Migraine]], [[Cluster Headache]])
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| == Diagnosis ==
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| ===Ottawa SAH Rules<ref>Ottawa SAH Rule JAMA. 2013 Sep 25;310(12):1248-55. doi: 10.1001/jama.2013.278018</ref>===
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| ''Never has been externally and prospectively validated, authors caution implementation into routine use''
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| *100% sensitive to rule out SAH (97.1%-100%)
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| *Can exclude SAH if all of the following are true
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| **Age < 40
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| **No Neck pain or stiffness
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| **No Witnessed LOC
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| **No onset during exertion
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| **No Thunderclap symptomatology (max intensity at honest)
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| **No limited neck flexion on physical exam
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| '''If concerned for SAH and CT normal strongly consider LP'''
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| ===Non-Contrast Head CT ===
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| ====Sensitivity====
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| *Within 6hr of onset of symptoms: Near 100% Sn<ref>Perry JJ, et al. Sensitivity of computed tomography performed within six hours of onset of headache for diagnosis of subarachnoid haemorrhage: prospective cohort study. BMJ. 2011; 343:d4277.
</ref>
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| *Within 12hr of onset of symptoms: 98% Sn
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| *Within 24hr of onset of symptoms: 93% Sn<ref>van Gijn J and van Dongen KJ. The time course of aneurysmal haemorrhage on computed tomograms. Neuroradiology. 1982; 23:153–156.</ref>
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| *Within 5d of onset of symptoms: <60% Sn
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| *Not as sensitive/specific for minor bleeds
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| ====Findings====
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| *SAH due to aneurysm - look in cisterns (esp. suprasellar cistern)
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| *SAH due to trauma - look at convexities of frontal and 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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| **Note: 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 (60% of pts)
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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 2hr after bleed to develop (beware of false negative if measure early)
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| **Sn (93%) / Sp (95%) highest after 12hr
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| *If unable to obtain CSF consider CTA
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| **CTA also highly sensitive for predicting delayed cerebral ischemia
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| ==Workup==
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| *Brain CT without contrast
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| *[[LP]]
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| == Treatment ==
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| 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.
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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]] --> (Prothrombin complex conc or [[FFP]]) + vitamin K
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| #*[[Aspirin]] --> [[DDAVP]]
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| #*[[Plavix]] --> [[Platelets]]
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| #[[Nimodipine]]
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| #*Prevents vasospasm (associated with improved neuro outcomes and decreased cerebral infarction)
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| #*Give 60mg q4hr PO or NGT only (never IV) within 96hr of symptom onset. NNT 13 to prevent one poor outcome
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| #*Keep an eye on BP for fluctuations
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| #[[Magneisum sulfate]]
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| #*Controversial; prevents vasospasm acting as NMDA antagonist and a calcium channel blocker; maintain b/w 2-2.5 mmol/L
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| #Seizure prophylaxis
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| #*Controversial; 3 day course may be preferable
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| #*[[Phenytoin]], [[levetiracetam]], [[carbamazepine]] and [[phenobarb]]. Phenytoin can be associated with worse neurologic & cognitive outcome
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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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| #Aneurysm treatment
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| #*Surgical clipping and endovascular coiling are definitive tx
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| #*Antifibrinolytic - Controversial; if delayed aneurysmal tx, consider short term therapy (<72 hrs) with TXA or aminocaproic acid
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| {{AHA SAH BP Guidelines}}
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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 started after aneurysm has been treated
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| ***Tx for symptomatic vasospasm: Triple-H therapy (hemodilution + induced hypertension (pressors) + hypervolemia), ballon angioplasty, or intra-arterial vasodilators.
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| ****Studies have not provided strong evidence of benefit Triple-H therapy
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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/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 w/in 24hr
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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 H2O restriction)
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| **Rarely due to cerebral salt-wasting
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| ***Volume depleted, so treat with isotonic saline
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| == Prognosis ==
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| === Hunt and Hess ===
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| Subjective terminology, but good interobserver variability
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| {| class="wikitable"
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| | align="center" style="background:#f0f0f0;"|'''Grade'''
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| | align="center" style="background:#f0f0f0;"|'''Description'''
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| | align="center" style="background:#f0f0f0;"|'''Survival Rate'''
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| |-
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| | Grade 0: ||Unruptured aneurysm||-
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| |-
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| | Grade 1: ||Asymptomatic or mild HA and slight nuchal rigidity||70%
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| |-
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| | Grade 1a: ||No acute meningeal/brain reaction, with fixed neurological def||-
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| |-
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| | Grade 2: ||Moderate to severe HA, stiff neck, no neurologic deficit except CN palsy||60%
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| |-
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| | Grade 3: ||Mild mental status change (drowsy or confused), mild focal neurologic deficit||50%
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| |-
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| | Grade 4: ||Stupor or moderate to severe hemiparesis||20%
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| |-
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| | Grade 5: ||Coma or decerebrate rigidity||10%
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| |}
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| <br>
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| :Grade 1 or 2 have curable disease
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| :Add one grade for serious systemic disease (HTN, DM, severe atherosclerosis, COPD)
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| === World Federation of Neurosurgical Societies (WFNS) ===
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| Objective terminology, and fair interobserver variability
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| *Grade 1: GCS of 15, no motor deficits
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| *Grade 2: GCS of 13 or 14, no motor deficits
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| *Grade 3: GCS of 13 or 14, with motor deficits
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| *Grade 4: GCS of 7–12, with or without motor deficits
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| *Grade 5: GCS of 3–6, with or without motor deficits
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| Other scales are also available, including the Ogilvy and Carter scale (comprehensive, yet complex), and the Fisher scale or Claassen grading system (vasospasm index risk).
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| Note: First-degree relatives are at 2-5 fold increase in SAH, so screening is considered on individual basis.
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| == See Also ==
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| *[[Intracranial Hemorrhage (Main)]]
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| *[[Head Trauma]]
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| == Source ==
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| <references/>
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| [[Category:Neuro]] | |
