Ver el código de «Ischemic stroke»

==Background==
*'''Acute ischemia of brain parenchyma''' due to arterial occlusion
*'''Most common type of stroke''' (~87% of all strokes)
*'''5th leading cause of death''' in the US; '''leading cause of long-term disability'''
*'''"Time is brain"''': ~1.9 million neurons lost per minute of untreated large vessel occlusion<ref>Saver JL. Time is brain — quantified. ''Stroke''. 2006;37(1):263-266. PMID 16339467</ref>
*'''IV tPA window: up to 4.5 hours from last known well'''
*'''Thrombectomy window: up to 24 hours''' in select patients with large vessel occlusion (LVO) and favorable imaging

===Etiology===
*'''Large artery atherosclerosis''' (~25%): carotid stenosis, intracranial atherosclerosis
*'''Cardioembolism''' (~25%): [[atrial fibrillation]] (most common), valvular disease, LV thrombus
*'''Small vessel disease''' (lacunar, ~20%): lipohyalinosis of penetrating arteries (hypertension)
*'''Other determined''' (~5%): dissection, [[hypercoagulable state]], vasculitis, sickle cell
*'''Cryptogenic/undetermined''' (~25%)

==Clinical Features==
*'''Sudden onset focal neurologic deficit''' (maximal at onset or rapidly progressive)
*'''Last known well (LKW) time''' is the most critical historical datapoint

===Anterior Circulation (Carotid Territory)===
*'''MCA stroke''' (most common): contralateral face/arm > leg weakness, hemisensory loss, aphasia (dominant hemisphere) or neglect (nondominant), gaze deviation toward lesion
*'''ACA stroke''': contralateral leg > arm weakness, urinary incontinence, abulia
*'''ICA occlusion''': entire MCA territory ± ACA territory

===Posterior Circulation (Vertebrobasilar)===
*'''PCA stroke''': homonymous hemianopia, memory deficits, alexia without agraphia
*'''Basilar occlusion''' ('''emergency'''): bilateral motor/sensory deficits, cranial nerve palsies, coma, locked-in syndrome
*'''Cerebellar stroke''': ataxia, vertigo, nystagmus, headache → '''can cause brainstem compression''' (surgical emergency)
*'''HINTS exam''' to distinguish cerebellar/brainstem stroke from peripheral vertigo

===Mimics (Important to Recognize)===
*[[Hypoglycemia]] ('''always check glucose'''), seizure with Todd paralysis, [[Bell palsy]], migraine with aura, conversion disorder, intracranial mass

==Differential Diagnosis==
*[[Hemorrhagic stroke]] (cannot distinguish clinically — '''MUST image''')
*[[Hypoglycemia]]
*Postictal (Todd) paralysis
*Complicated migraine
*[[Bell palsy]]
*Intracranial mass/abscess
*Psychogenic/conversion
*Drug toxicity

==Evaluation==
===Critical First Steps===
*'''Blood glucose''' ('''POC STAT''' — hypoglycemia mimics stroke and must be corrected)
*'''Non-contrast CT head''' (rule out hemorrhage — '''ONLY test required before tPA''')
*'''CT angiography (CTA) head and neck''': identify '''large vessel occlusion (LVO)''' for thrombectomy candidacy
*'''CT perfusion (CTP)''': '''ischemic penumbra''' assessment for extended-window cases

===NIHSS Score===
*Standardized neurologic exam scoring (0-42)
*Correlates with stroke severity and helps guide treatment decisions
*'''NIHSS ≥6''': consider LVO until proven otherwise; higher scores = worse prognosis
*Use the [[NIHSS calculator]] for scoring

===Additional Studies===
*'''ECG''': atrial fibrillation, MI
*'''CBC, BMP, coagulation studies''' (PT/INR, PTT)
*'''Troponin''' (concurrent cardiac events)
*'''A1c, lipid panel''' (risk factor assessment, not urgent)
*Echocardiography (identify cardioembolic source)

===Do NOT Delay tPA for:===
*Labs (except glucose)
*CTA/CTP
*Complete history
*'''Only glucose and NCCT are needed before tPA'''

==Management==
===IV Alteplase (tPA)===
*'''Indicated within 4.5 hours of last known well (LKW)'''<ref>Powers WJ, et al. Guidelines for the early management of patients with acute ischemic stroke: 2019 update to the 2018 guidelines. ''Stroke''. 2019;50(12):e344-e418. PMID 31662037</ref>
*'''Dose: 0.9 mg/kg IV''' (max 90 mg):
**'''10% as bolus''' over 1 minute
**'''Remaining 90% infused over 60 minutes'''
*'''Extended window (3-4.5 hours)''': additional exclusions apply (age >80, NIHSS >25, oral anticoagulant use, history of DM + prior stroke)
*'''Key contraindications''':
**Active internal bleeding, recent intracranial surgery/trauma (3 months)
**Intracranial hemorrhage on CT
**SBP >185 or DBP >110 (lower BP first)
**Platelets <100,000, INR >1.7, aPTT elevated
**Blood glucose <50 mg/dL
*'''Tenecteplase''' (0.25 mg/kg IV bolus, max 25 mg): emerging alternative, single-bolus dosing, favorable in LVO<ref>Campbell BCV, et al. Tenecteplase versus alteplase before thrombectomy for ischemic stroke (EXTEND-IA TNK). ''N Engl J Med''. 2018;378(17):1573-1582. PMID 29694815</ref>

===Endovascular Thrombectomy===
*'''Standard window: within 6 hours''' of LKW for anterior LVO
*'''Extended window: up to 24 hours''' with '''favorable perfusion imaging''' (DAWN and DEFUSE 3 trials)<ref>Nogueira RG, et al. Thrombectomy 6 to 24 hours after stroke with a mismatch between deficit and infarct (DAWN). ''N Engl J Med''. 2018;378(1):11-21. PMID 29129157</ref>
*'''Target vessels''': ICA, M1, and sometimes M2 MCA, basilar artery
*'''NNT = ~2.6''' for reduced disability (one of the most effective treatments in medicine)
*Thrombectomy is ADDITIVE to IV tPA — '''give tPA first, do not delay for thrombectomy'''

===Blood Pressure Management===
*'''If tPA candidate''': lower BP to '''<185/110 before tPA'''; maintain '''<180/105 for 24h after'''
*'''If NOT receiving tPA''': permissive hypertension '''up to 220/120''' (avoid aggressive lowering)
*'''Post-thrombectomy with successful recanalization''': target '''SBP <140''' (BP-TARGET trial)
*Preferred agents: labetalol, nicardipine

===General Management===
*'''NPO until swallow assessment''' (aspiration risk)
*'''Aspirin 325 mg PO/PR''' within 24-48 hours (if no tPA in past 24h)
*'''DVT prophylaxis''' (SCDs immediately; chemical prophylaxis after 24-48h)
*'''Glucose management''': target 140-180 mg/dL; treat hypoglycemia; avoid hyperglycemia
*'''Avoid fever''' (antipyretics for temp >38°C)
*'''Avoid hypotension''' (maintain adequate cerebral perfusion)

==Disposition==
*'''All acute stroke patients: admit to stroke unit/neuro ICU'''
*'''Transfer to comprehensive stroke center''' if LVO identified and thrombectomy capability unavailable
*'''Do NOT delay tPA for transfer''' — give tPA at presenting hospital then transfer ("drip and ship")
*Neurology and neurointerventional consultation
*Start workup for stroke etiology (echo, prolonged cardiac monitoring, vascular imaging)

==See Also==
*[[Hemorrhagic stroke]]
*[[Subarachnoid hemorrhage]]
*[[Transient ischemic attack]]
*[[NIHSS calculator]]
*[[Atrial fibrillation]]
*[[Stroke mimics]]

==References==
<references/>
*Goyal M, et al. Endovascular thrombectomy after large-vessel ischaemic stroke: a meta-analysis. ''Lancet''. 2016;387(10029):1723-1731. PMID 26898852
*Hacke W, et al. Thrombolysis with alteplase 3 to 4.5 hours after acute ischemic stroke (ECASS III). ''N Engl J Med''. 2008;359(13):1317-1329. PMID 18815396

[[Category:Neurology]]
[[Category:Critical Care]]