Pathophysiology

Ischemic

Ischemic strokes are either atherosclerotic or embolic. Athlerosclerotic strokes have vascular disease in cerebral vessels, which can rupture in a similar manner to an MI, occluding cerebral vessels. Embolic strokes result from an arterial clot (or in rare cases a DVT in pts with a septal malformation), most commonly the result of A-fib. These clots mobilize and enter the cerebral vasculature, occluding arterial blood supply. Both circumstances lead to anoxic brain injury. Ischemic strokes are much more common than hemorrhagic strokes

Hemorrhagic

Hemorrhagic strokes often result from a cerebral vasculature aneurism or from severe uncrontrolled HTN. This leads to the vessel rupturing and this rupture produces anoxic brain injury in the area supplied by the ruptured vessel, as well as some direct neuronal damage from the hematoma.

Risk Factors

• Age
• FHx
• Male
• AA, Asian, or Hispanic
• Low birth wt
• HLD
• HTN
• DM
• CVD, esp valvular and dysrhythmic diseases
  • Evaluate CHA₂D₂-VASc score in A-Fib
• Drug / EtOH use
• Smoking Hx
• Obesity
• Previous Stroke

Management

SSx

• Facial asymmetry
• Appendage weakness / Ataxia
• Speech alterations (slurring, aphasias, etc)
• Time is brain
• Diplopia
• HA (more common in hemorrhagic)

Initial Managment

Labs

• Conduct NIHSS (National Institutes of Health Stroke Scale)
• Head CT to r/o hemorrhagic stroke
• Monitor BP / O₂Sat
• BG
• BMP
• CBC
• INR / aPTT
• EKG
• Echo
• Pt is NPO until swallow study conducted

Initial Therapies

• Manage BG if abnormal
  • Hypoglycemia can result in stroke SSx
  • Hyperglycemia above 180 mg/dL can result in higher morbidity / mortality
• Consider thrombolytics for ischemic strokes (must r/o hemorrhagic)
• Manage HTN to < 220/120 for non-thrombolytic pts, < 180/105 for thrombolysis
  • IV antihypertensives warranted, do not lower BP excessively, as elevated BP may help perfuse partially occluded areas
  • Agressive BP control can limit stroke recurrence, long-term neuro deficits, an decrease risk of cerebral edema; however concern from above usually wins, attempt to balance (i.e 150s instead of 170s or 110s)

Thrombolysis

Dosing

• Must satisfy inclusion / exclusion criteria below
• 0.9 mg/kg NTE 90mg Total dose
  • 10% (0.09 mg/kg) IVPB over 1min
  • 90% (0.81 mg/kg) IV over 60min
• Give w/i 60min of arrival
• Keep BP < 180/105
  • Monitor q15min x2h then q30min x 6h then q1h x16hr
  • Can begin to lower to outpt goal after 24h
• Avoid all antiplatelets and anticoagulants for 24hr post-admin

SEs

• Bleeding
• Stroke Conversion
• Cerebral Edema

Inclusion Criteria

• Ischemic stroke confirmed by imaging
• < 3hrs from SSx onset
  • Extended interval available, see below
  • Some evidence for imaging-based determination of thrombolysis eligbility here, but not currently in guidelines
• ≥ 18yo

Exclusion Criteria

• Evidence of active internal bleed
• Hx of intracranial hemorrhage
• Previous stroke or head trauma in less than 3mo
• GI or GU hemorrhage in ≤ 21d
• Major surgery in ≤ 14d
• MI in ≤ 3mo
• BP > 185/110 at administration time
• BG < 50 mg/dL
• Plt < 100k
• Current anticoag w/ INR > 1.7 or aPTT > 45s
  • NOACs CI tPA Reversible exclusion criteria

Extended tPA Window

• 4.5hrs after SSx onset
• Add the following to the exclusion criteria
  • Age ≥ 80
  • Hx of Stroke w/ DM
  • Any recent anticoag use
  • NIHSS > 25

BP Control

• Use common IV antihypertensives discussed in HTN Crisis section
• Labetalol 10-20mg IVPB q10-20min NTE 300mg
• Nicardipine 5mg/hr IV titrated q5min NTE 15 mg/hr
• Nitroprusside 0.5-10 mcg/kg/min titrated (preferable if DBP > 140)

Prophylaxis

Modify risk factors appropriately and initiate pt on antiplatelet agent for Secondary Prevention. 81mg ASA PO QD may be useful in primary prevention in women, but not commonly recommended w/o high cardiovascular risk. Men should be initiated on 81mg ASA PO QD only if they have concomittent CVD (as indicated in CVD guidelines for the managment of MI secondary prevention or angina managment).

Secondary Prevention

• ASA 325 QD x2-4wks then 81mg PO QD
• Dipyridamole / ASA 200mg / 25mg PO BID for non-embolic ischemic strokes
  • HA and GI bleeding
• Clopidogrel 75mg PO QD
  • Primarily for use in ASA allergy
• ASA / Clopidogrel 81mg / 75mg PO QD x21d
  • Second line, no evidence better than ASA alone
• If cardioembolic stroke from A-Fib, provide anticoagulation appropriate for A-Fib

Hemorrhagic Stroke Management

• Reverse any anticoagulation if possible, then surgical interventions if possible
• Control BP to < 180/110 in 24hr, then < 160/90 in next 24hr, then < 140/90 outpt
• Nimodipine 60mg Q4H x21d after subarachnoid bleed can help prevent vasospams

Antidepressants

Pts who suffer a stroke frequently become depressed. Pts should be initiated on prophylactic antidepressants (SSRIs 1st) to allow time for therapeutic effect.