Subarachnoid Bleeds. Under the Spider via deepthought 1 / 22

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1 Subarachnoid Bleeds Under the Spider via deepthought 1 / 22

2 SAH: symptoms worst headache of my life Sudden-onset Severe w max intensity in seconds = thunderclap Sentinel headache in ~10-40% in aneurysmal Warning leak ~2-8 wks before overt SAH ~1% of all ED headaches Altered cognition: Brief loss of consciousness / encephalopathy (from mild lethargy to coma) If convexity-restricted may present w transient focal motor/sensory symptoms similar to seizures seizures, nausea/vomiting, meningismus, photophobia Onset context: Most commonly occurs w/o signifcant exertion - ADLs (may occur during physical/psych stress) 2 / 22

3 SAH: overview Bleeding w/i subarachnoid space = between arachnoid & pia mater (normally flled w CSF) ~3 to 10% of all USA strokes Incidence variable depending on region (per 100k adults / yr): China 2, US ~14.5, Finland 22.5 Age-associated increase in risk - mean onset 50 yo But younger vs. other stroke types Prognosis Mortality range broad: 8 to 65%, ~10-15% prehospital mortality ~½ survivors w signifcant impact on quality of life 3 / 22

4 SAH: etiologies Traumatic - most common spontaneous/non-traumatic Most aneurysmal ~80% ~20% non-aneurysmal ~10% no clear vascular abnormality 4 / 22

5 SAH: initial diagnosis Following for those presenting w typical symptoms Non-contrast head CT: Sensitivity decreases from onset as blood diluted by CSF Approaches 100% if within 6 hrs from bleed onset False negative approx: < 1.5 in 1000 >90% if w/i 24 hrs of bleed ~50% days 5-7 LP if suspicion w normal CT: Unequivocal positive: Xanthochromia: spectrophotometry OR visual inspection Lyzed RBC releasing Hg -> oxyhg (~pink, hrs ) + BR (yellow, up to 12 hrs) Could get false negatives if < 12 hrs from onset elevated RBC unchanged tubes 1-4 Dr. James Heilman via wikipedia May also see elevated opening pressure If LP equivocal (e.g. no xanthochromia or only 1 tube analyzed) CTA or conventional angio LP confounders Traumatic taps or sample handling error - false RBC elevation Spec for xanthochromia may have poor specifcity / high false positives 5 / 22

6 SAH: etiology determination Angiography - digital subtraction angiography = gold standard subtracting pre-contrast image from post-contrast image Risk of permanent & transient complications 1.8% in SAH (3.7% in TIA) ~15-20% w SAH are w/o vascular lesion on initial 4-vessel angiography If initial angio negative -> repeat in 4-14 days re potential false negatives Up to ~24% negative studies w subsequent aneurysm found Possible reasons: technical/read error, small aneurysm, obscuration due to vasospasm, hematoma, or thrombosis in aneurysm If repeat angio negative: MRI brain/spinal-cord eval source bleed CTA/MRA Lower resolution, can identify aneurysms ~2-5mm Vs. DSA sensitivity is ~83-98% 6 / 22

7 SAH: initial angio negative Perimesencephalic = majority in some case series (to ~⅔) Blood isolated to perimesencephalic cisterns anterior to brainstem - Generally benign course Occult aneurysm - up to 24% Vascular malformations / AVM - intracranial or spinal (<10%) Intracranial arterial dissection - some studies up to ~4.5% Less common: Sickle cell Pituitary apoplexy Cerebral venous thrombosis Bleeding disorders Traumatic Cocaine (aneurysmal & non) Cerebral amyloid angiopathy Tumors Vasculitis RCVS Post-endarterectomy hyperperfusion 7 / 22

8 SAH: focal neuro defcits (in ~10%) sign Possible localization/etiology CN3 palsy PCOM > PCA & Sup Cb art aneurysms CN6 palsy Hemiparesis + (aphasia or visuospatial neglect) Other ophthalmoplegia Unilat viz loss / bitemporal hemianopia Impaired LOC & upgaze Brainstem signs Neck stiffness retinal/subhyaloid hemorrhages Preretinal hemorrhages (Terson syndrome) From continuum 2015 Increased ICP MCA aneurysm, thick subarachnoid clots, IPH ICA aneurysm pushing on cavernous sinus ICA aneurysm pushing on optic nerve or chiasm Dorsal midbrain pressure from hydrocephalus Compression from basilar artery aneurysm SAH causing meningeal irritation Sudden increase in ICP Vitreous hemorrhage due to severe/spiking ICP 8 / 22

9 Aneurysmal SAH Intracranial aneurysms in 1-2% of population Types: saccular (aka berry) aneurysms - balloon-like vessel wall outpouchings w neck to parent vessel & more fragile dome Typically at branch points along intracranial arteries - thought hemodynamic stress weakens wall between branches Fusiform aneurysm: dilation of main vessel (less rupture-prone vs. saccular) Risk factors for aneurysms Family history in 1st-degree relatives Some connective tissue disorders: e.g. Ehlers-Danlos, Marfan s Polycystic kidney disease Risk for rupture: Size > 7mm HTN, current smoking, EtOH abuse, sympathomimetics, labile BP 9 / 22

10 Aneurysmal SAH: locations Acom ~30% Pcom ~25% Arising from ICA may cause painful CN3 palsy MCA ~20% Vertebrobasilar ~15% Source: Blumenfeld 10 / 22

11 Aneurysm to symptoms Bleeding/rupture Unruptured large aneurysms may cause symptoms via mass efect 11 / 22

12 SAH grading: Hunt-Hess Grade Neuro status 1 Asymptomatic or mild HA & slight nuchal rigidity 2 Severe HA, stif neck no neuro defcit except cranial nerve palsy 3 Drowsy or confused, mild focal neuro defcit 4 stuporous, moderate or severe hemiparesis 5 Coma, decerebrate posturing Advance +1 for presence of: HTN, DM, severe DM, severe arteriosclerosis, chronic pulmonary disease, or vasospasm on angiography Conficting data re utility/prognosis: attempts to grade encephalopathy severity w long-term neurologic outcome 12 / 22

13 SAH grading: mfisher - vasospasm risk Blood appearance on CT vasospam 0 No blood 0% 1 Thin SAH (focal or diffuse) w/o IVH 24% 2 Thin SAH (focal or diffuse) w IVH 33% 3 Thick SAH (focal or diffuse) w/o IVH 33% 4 Thick SAH (focal or diffuse) w IVH 40% Depth: Thin: < 1mm Thick: > 1mm Srcs include: radiopaedia Fischer scales = index of vasospasm Not correlated w clinical outcome 13 / 22

14 SAH: complications Re-bleeding/rupture (mainly hrs) Vasospasm (~70% aneurysmal) Delayed ischemia (~⅓ of aneurysmal) Hydrocephalus ( 15-85% ) / Increased ICP Seizures (~20% aneurysmal) hypona Cardiac abnormalities Hypothalamic dysfunction 14 / 22

15 SAH: further general w/u Serologies: CBC, basic chemistries, coags, tox-screen EKG If initial-angio negative: MRI brain & spinal cord with and without contrast 15 / 22

16 Aneurysmal SAH: med management Nimodipine 60 q4 hrs for 21 days Ideally w/i 4 days of SAH Calcium channel blocker No evidence reduces angiographic or symptomatic vasospasm Decreases risk of delayed cerebral ischemia through unclear mechanism However improves outcomes -> thus standard of care decreases odds of poor outcome by ~1/3 Decreased odds defcit, mortality, or both, infarction rate Slightly decreased mortality NNT to prevent 1 poor outcome: ~13 Treatment efect correlated w severity of SAH Sfx: hypotension, constipation Anti-seizure drugs: routine prophylaxis not recommended despite sz in up to 20% 16 / 22

17 Aneurysmal SAH: management Transcranial doppler ultrasound Detect vasospasm earlier Monitor Na closely If detect signifcant delayed ischemia w or w/o vasospasm: triple H therapy to improve perfusion Hypervolemia - IVF Hypertension - alpha-adrenergic agents (safer after clip/coil) But generally: MAP < 110 & SBP < 160 (& taking into account pre-bleed BPs) hemodilution May consider cerebral angioplasty and/or selective intraarterial vasodilator therapy Hydrocephalus - thought from blood blocking normal outfow of days to wks If causing encephalopathy - place EVD Lumbar drain w reduced vasospasm but contraindications: hydrocephalus + IPH 17 / 22

18 SAH: ruptured aneurysm Mortality ~25-50% Re-rupture risk: 1st 24 hrs: 4-15% 2 weeks ~20% Elevated for 30 days if untreated Prevent re-rupture: Medical: Goal normal: blood volume, temp, glc, lyte balance, ventilation DVT ppx: SCDs + after 24 hrs unfractionated heparin unless procedures Maybe antifbrinolytics (can increase DVT & delayed cerebral ischemia) procedural: Endovascular intervention - e.g. coiling - may be better 1 year functional outcomes based on ISAT & BRAT trials Open surgery - clipping w craniotomy (bone replaced) or craniectomy (not replaced) 18 / 22

19 Aneurysmal SAH: vasospasm Narrowing of imageable vessels post SAH ~70% of patients Course (from days post rupture): starts ~3-4 days peak ~7-10 days Resolves ~14-21 days 19 / 22

20 SAH: non-aneurysmal management Perimesencephalic Treat as if aneurysmal until followup imaging (including w nimodipine) Unclear if nimodipine benefts, but little data for harm Hemispheric - do not need to treat with nimodipine Traumatic: vasospasm not usually seen re nimodipine If severe TBI: 7 day course of anti-seizure drug recommended (along w consideration of EEG if coma) 20 / 22

21 SAH: prognosis ~25% patients estimated to die pre-hospital ~50% overall mortality srcs include: Blumenfeld 21 / 22

22 sources/refs UpToDate Clinical manifestations and diagnosis of aneurysmal subarachnoid hemorrhage Nonaneurysmal subarachnoid hemorrhage Perimesencephalic nonaneurysmal subarachnoid hemorrhage Subarachnoid hemorrhage grading scales Treatment of aneurysmal subarachnoid hemorrhage Management of acute severe traumatic brain injury Continuum 2015: Diagnosis and Management of Subarachnoid Hemorrhage Neuroanatomy through Clinical Cases by Hal Blumenfeld, second edition 2010 Other articles: NEJM 2017 Subarachnoid hemorrhage article by Lawton & Vates, DOI: /NEJMcp Sensitivity of Early Brain Computed Tomography to Exclude Aneurysmal Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis. Dubosh et al. Stroke DOI: /STROKEAHA Avoiding pitfalls in the diagnosis of subarachnoid hemorrhage. Edlow and Caplan. NEJM DOI: /NEJM Should spectrophotometry be used to identify xanthochromia in the cerebrospinal fuid of alert patients suspected of having subarachnoid hemorrhage? Perry et al Stroke. DOI: /01.STR SAH image source: 22 / 22