Ischemic Stroke

Hey all,  today I've posted some notes on ischemic strokes. Enjoy!

Causes of stroke:

·       Embolic (75%): arterial, cardiac, paradoxical, cryptogenic (25 % may be paroxysmal a. fib)

·       Thrombotic (25%): large vessel and small vessel (lacunar)

·       Other causes: dissection, vasculitis, vasospasm

·       DDx: Seizure with todd’s paresis, hypoglycemia

Stroke Syndromes:

·       Opthalmic artery: amaurosis fugax

·       Anterior cerebral artery: hemiplegia (leg > arm), sensory deficits, primitive reflexes

·       MCA: hemiplegia (arm/face > leg), aphasia if dominant hemisphere, neglect if nondominant, gaze towards side of lesion

·       PCA: visual deficits, i.e contralateral homonymous hemianopsia

·       Cerebellar: vertigo, Nx+ Vx, diplopia, dysarthria, ataxia

·       Lacunar: pure sensory or motor loss

·       PICA (posterior inferior cerebellar artery): lateral medulla infarcted, loss of pain +temp contralateral body and ipsilateral face (spinothalamic tract)

Workup:

·       History + physical exam : NIHSS (Nat. institute of health stroke scale)

a.     LOC objective score - alert, response to stimuli

       LOC questions-- how old, what month

       LOC commands-- open then close eyes, grip and release hand

b.     Best gaze (follow my finger)

       Visual fields (confrontation)

       Facial palsy (show me your teeth, raise eyebrows)

c.     Arm motor (extended + palms down, score both)

       Leg motor (raise 30 degrees, score both)

       Limb ataxia (finger to nose, heal to shin);

d.     Sensory (use pinprick)

e.     Best language (describe, name, read)

       Dysarthria (read these words)

       Extinction/inattention (look for neglect)

·       15 items, each scored 0-3/4, > 25 = very severe

·       ABCs, IV, O₂, monitor, neurovitals

·       Screening bloodwork, CXR + ECG

·       Neuroimaging: CT/CTA or MR/MRA. If cannot get vascular imaging then get non-contrast CT

·       Neuroimaging findings: parenchymal hypodensity, swelling causing sulcal effacement + loss of grey/white matter differentiation, hyperdense MCA sign

tPA (tissue plasminogen activator)

·       For acute ischemic stroke within 4.5 hrs of symptom onset, NIHSS > 3 or aphasia

·       .9 mg/kg, to a maximum of 90 mg/kg, 10% bolus then the rest over an hour

·       ASPECTS score for CT scan (if less than 7, usually avoid tPA because of risk of hemorrhage)

·       Endovascular therapy may be an option for patients who do not qualify for tPA because of window, bleeding risk etc.

·       Many contraindications: ICH 6 mos, CVA 3 mos, major Sx, confounding dx, HTN (> 185/110), plts < 100, INR > 1.7

·       tPA can reduce disability in CVA

·       NINDS (1995): tPA within 3 hrs led to better outcome

·       ECAS III (2008): tPA between 3 and 4.5 hrs led to less disability (mRS, NIHSS), NNT 10

·       IST3 (2012): tPA up to 6 hrs- no difference in mortality/morbidity, but perhaps improvement in some risk groups such as older patients (>80), higher NIHSS scores, early Rx

Management:

·       Swallowing screen

·       Remember to think of seizures in periCVA period (10 %); Rx with benzos IV; if one off no other meds, if ongoing then load with anti Sz med

·       Blood pressure: If using tPA then target 185 / 110 to avoid risk of bleed; otherwise target < 220 /120 in order to allow perfusion of penumbra but avoid bleed. Drop by 25 % / 24 hrs, use labetolol or NTG

·       Anti-platelet: ASA 160 mg then daily 82 mg (if tPA wait 24 hrs), if already on ASA switch to Plavix leads to reduced CVA recurrence; can always start ASA, Plavix, or Aggrenox (ASA + dipyridamole)

·       Hemicraniectomy for ICP should be considered in massive MCA strokes where infarct size > 50% territory, GCS less than 8 at 24 hours, worsening imaging etc. to prevent death within 48 hrs

·       Remember for increased ICP: elevate HOB, hyperventilation, hypertonic solution

·       CVA cause workup:

a.     Vascular stenosis (i.e carotid): dopplers/CTA/MRA; endarterectomy if > 50 stenosis, NNT 6 if > 70 %

b.     Arrhythmia: telemetry

c.     ASD/PFO/thrombus: echo

d.     Coagulopathy: coag screen for ALPAs, ATIII, Protein C/S, prothrombin, homocysteine, PNH

e.     Vaculitis: esr, crp, ana, ancas, c3/c4

Long-term management (similar to all secondary CVD mgmt.):

Lifestyle-

·       Healthy diet low in sat. fats, cholesterol, and salt; fruit more than five servings / day

·       Exercise regularly, avoid obesity

·       Stick to safe drinking guidelines; stop smoking

·       Avoid HRTs or OCP in those with CVA

Risk Factors-

·       HTN: aim for less than 140/90; most important risk factor; ACE inhibitor/diuretic combo

·       Hypercholesterolemia: All CVA patients should be on statin, SPARCL study: atorvastatin 80 mg led to NNT 50 to prevent CVA; can target LDL of <2 or 50% reduction

·       Screen for DM, HBA1C > 6.5

·       Screen for OSA, as RF for CVA and consequence of CVA, severe if AHI (episodes/hr) >=30