Lecture 10 - Stroke 1 Flashcards
Stroke is….
sudden loss of neurological function caused by vascular injury to the brain that lasts > 24hrs and is associated with neurological deficit
Transient ischemic attack…..
sudden focal loss of neurological function that lasts < 24hrs and is not associated with neurological deficit
risk factor for stroke
Ischemic vs Hemorrhagic Stroke
Ischemic = block
Hemorrhagic = most serious, cant give meds, vessel in brain burst
majority are ischemic (87% vs 13% hemorrhagic)
Collagen pathway for stroke
- adhesion
- activation of platelets
- aggregation of platelets
- platelet plug
Tissue Factor Pathway stroke
Thrombin activates Fibrinogen, causes Crosslinked fibrin leading to clot
Thrombin can also cause inflammation and activate platelets
Ischemic Penumbra
Normal Cerebral Blood flow = 50ml/100g/min
Core infarct = area of dead tissue, <8mL/100g/min
Penumbra is area around core = 8-35ml/100g/min…use therapy to hopefully reflow flow
Non-modifiable Risk Factors Stroke
Age
Gender (M>F)
FH
Race (AA>Hispanics> Asians)
Modifiable Risk Factors Stroke
HTN AFib/ CVD Hyperlipidemia Prior TIA/CVA DM Cartoid Stenosis CKD Lifestyle = Obesity, diety, heavy booze, smoking, inactivity
Single most modifiable risk factor for stroke?
HTN
Most important concept for determine if a patient is having a stroke?
History, When was the patient last seen normal
NIHSS scale
0 = no stroke 1-4 = minor stroke 5-15 = moderate stroke 15-20 =moderate/sever stroke 21-41 = severe stroke
Outcomes that NINDS study looked for?
Mortality
Safety
Neurologic deficit after 24hrs and 3 months
NINDS Study dosing
0.9mg/kg (90mg max) alteplase
10% bolus, 90% infusion
NINDS Study Inclusion Criteria for rt-PA
> 18 yr old
Clinical diagnosis of stroke with measurable defect
time of onset of stroke known and < 3hr
no evidence of intracranial hemorrhage on CT
Results of NINDS Study
Benefit:
No Difference in mortality/short term deficity
32% inc in # of pt returning to normal or minimal deficit in 90 days
Harm:
inc incidence of intracerebral hemorrhage (6.4% v 0.6%) in 1st 36hrs
Tenecteplase Vs Alteplase
Tenecteplase could be considered as an alternative in select patients with acute ischemic stroke with minor neurological I,pariment and no major intracranial occlusion
study shows tenecteplase is atleast non inferior, real world data shows the same…maybe some benefits
Tenecteplase Dose
0.25 mg/kg, max of 25 mg
same CI as alteplase
push over 5 seconds
Alteplase window extended to….
4.5hrs form originally 3 hrs
Heparin used for Ischemic Stroke?
Nah, no benefit shown
only in vertebrobasilar stroke
Heparin DVT prophylaxis after stroke
- Pt not receiving thrombolytics, usually started >24hr after stroke onset
- Pt receiving thrombolytics, wait 24hr after admin of it
Enoxaparin 40mg SubQ or Heparin 5000 unit SubQ TID
Is aspirin efficacious for acute treatment of stroke?
Overall, shows a small but significant benefit
Aspirin uses
should be started in 24-48hr after stroke onset in pt not receiving thrombolyics
Dose is 325mg po QD in acute setting
Blood pressure changes issues
Increasing too much can….
Inc brain edema
Inc hemorrhagic transformation
Inc vascular damage
If you go too low….may reduce perfusion to ischemic area and expand infarct size
1st line therapies for BP in stroke
Nicardipine
Labetalol
Clevidipine
Nitroprusside
