1. Stroke Syndromes
Dr. Gerrard Uy

2. Cerebrovascular Disease
ischemic stroke
hemorrhagic stroke
cerebrovascular anomalies such as intracranial aneurysms and arteriovenous malformations (AVMs)
Cause 200,000 deaths each year in the U.S.
Incidence increases with age

3. Stroke
Most strokes manifest by the abrupt onset of a focal neurologic deficit
Like patients were “struck by the hand of God”
Definition:
abrupt onset of a neurologic deficit that is attributable to a focal vascular cause

4. Definition of terms Thrombosis: inappropriate clotting
Embolism: migration of clots
Ischemia: loss of blood supply in a tissue due to impeded arterial flow or reduced venous drainage
Infarction: cell death

5. Definition of Terms
Cerebral ischemia is caused by a reduction in blood flow that lasts longer than several seconds
infarction - death of brain tissue
transient ischemic attack (TIA) - all neurologic signs and symptoms resolve within 24 h regardless of whether there is imaging evidence of new permanent brain injury

6. Hemorrhagic Stroke
Bleeding into subdural and epidural spaces is principally produced by trauma
SAHs are produced by trauma and rupture of intracranial aneurysms
Hemorrhage are classified by location
Often identified by CT scan

8. Approach to the patient
Rapid evaluation is essential for use of time sensitive treatments such as thrombolysis
Most patients with acute stroke do not seek medical attention because they are rarely in pain and they experience anosagnosia
Important clues pointing to stroke:
Hemiparesis
Changes in vision
Changes in gait
Disturbance in the ability to speak or understand
Sudden severe headache

9. Approach to the patient
Migraine can mimic stroke
The sensory and motor deficit tend to migrate slowly across a limb over minutes rather than seconds as with stroke
Once diagnosis of stroke is made, brain imaging study is necessary to determine the cause of the stroke whether ischemic or hemorrhagic
CT imaging is the standard imaging procedure

10. ISCHEMIC STROKE

11. Ischemic Stroke
Acute occlusion of an intracranial vessel causing reduction in blood flow to the brain region
The magnitude of flow reduction is a function of collateral blood flow
INFARCTION results when:
Cerebral blood flow of 0 (zero) in 4 – 10 mins
CBF <16-18 ml/ 100g tissue per min in 1 hour
CBF <20ml/100g tissue per min = ischemia
The tissue surrounding the infarction is ischemic and is called the ischemic penumbra

12. Pathophysiology
Ischemia produces necrosis by starving neurons of glucose
No glucose means no ATP production
No ATP, the neurons start to depolarize which in turn increases intracellular calcium levels to rise and glutamate to accumulate
Free radicals produced in this process will result in cellular dysfunction and death

13. Management of Acute Ischemic Stroke
First goal is to prevent or reverse brain injury
Check ABCs and treat hypoglycemia or hyperglycemia
Brain imaging to determine whether stroke is ischemic or hemorrhagic

14. Management of Acute Ischemic Stroke
6 categories to improve clinical outcome
Medical support
Intravenous thrombolysis
Endovascular techniques
Antithrombotic treatment
Neuroprotection
rehabilitation

15. Management of Acute Ischemic Stroke
Medical Support
Immediate goal is to optimize cerebral perfusion
Prevent complications such as infections, DVT, and bedsores
Maintain euglycemia
Treat fever
Manage hypertension
Use of IV Mannitol to raise serum osmolarity and prevent brain edema

16. Management of Acute Ischemic Stroke
Intravenous Thrombolysis:
NINDS rTPA stoke study showed benefit for IV rTPA in selected patients with acute stroke
Golden period is within 3 hrs of the onset of ischemic stroke (0.9 mg/kg – 10% as bolus and remainder over 1 hr)
The time of onset of stroke is defined as the time patient’s symptoms began or the time the patient was last seen normal

17. Management of Acute Ischemic Stroke
Indications for rTPA
Clinical diagnosis of stroke
Onset < 3 hrs
CT scan shows no hemorrhage or edema of > 1/3 of the MCA territory
Age > 18 yrs of age
consent

18. Management of Acute Ischemic Stroke
Contraindications
Sustained BP > 185/110 despite treatment
Plt < 100,000, hct < 25%, glucose <50 or >400 mg/dl
Use of heparin within 48 hrs, prolonged PTT, or elevated INR
Rapidly improving symptoms
Prior stroke or head injury within 3 months
Major surgery in preceding 14 days
Minor stroke symptoms
GI bleeding in preceding 21 days
Recent MI
Coma or Stupor

19. Management of Acute Ischemic Stroke
Endovascular Techniques
Usually done in occlusions of large vessels such as MCA, internal carotid artery, and basilar artery
Procedure is done intraarterially
Mechanical thrombectomy is an alternative

20. Management of Acute Ischemic Stroke
Antithrombotic Treatment
Platelet inhibition
Aspirin is the only antiplatelet agent that has been proven effective for the acute treatment of ischemic stroke
Usually given within 48 hrs of stroke onset
Anticoagulation
Has shown no benefit in the primary treatment of atherothrombotic cerebral ischemia

21. Management of Acute Ischemic Stroke
Neuroprotection
To provide a treatment that prolongs the brain’s tolerance to ischemia
Most common neuroprotective drug:
Citicoline – reduces the rate of death and disability

22. Management of Acute Ischemic Stroke
Rehabilitation
to improve neurologic outcomes and reduce mortality
Directed towards educating the patient and family about the patient’s neurologic deficit, preventing complications of immobility and providing encouragement and instruction in overcoming the deficit
Goal is to return the patient home and to maximize recovery

23. Causes of Ischemic Stroke
establishing a cause is essential in reducing the risk of recurrence
30% of strokes remain unexplained despite extensive evaluation
Focus on: atrial fibrillation and carotid atherosclerosis

24. Causes of Ischemic Stroke

25. Cardioembolic Stroke Responsible for 20% of all ischemic strokes
embolism of thrombotic material forming on the atrial or ventricular wall or the left heart valves
thrombi then detach and embolize into the arterial circulation
Embolic strokes tend to be sudden in onset, with maximum neurologic deficit at once

26. Cardioembolic Stroke
Emboli from the heart most often lodge in the MCA, PCA, and infrequently ACA
Nonrheumatic atrial fibrillation is the most common cause of cerebral embolism overall
Patient’s with atrial fibrillation have an average annual risk of 5%
Left atrial enlargement and CHF are additional risk factors for the formation of atrial thrombi

27. Cardioembolic Stroke causes:
nonrheumatic atrial fibrillation MI
prosthetic valves
rheumatic heart disease
ischemic cardiomyopathy

28. Carotid Atherosclerosis
10% of all ischemic strokes
frequently within the common carotid bifurcation and proximal internal carotid artery
RISK FACTORS:
Male gender, older age, smoking, hypertension, diabetes, and hypercholesterolemia

29. Other causes of stroke Intracranial Atherosclerosis
Dissection of Internal Carotid Artery
Hypercoagulability
Venous sinus thrombosis
Fibromuscular dysplasia
Vasculitis
Drugs (amphetamines, cocaine, phenylpropanolamine)

30. Transient Ischemic Attack (TIA)
Episodes of stroke symptoms that last briefly
Duration < 24 hrs
May arise from emboli to the brain or from in situ thrombosis
Amaurosis fugax – transient monocular blindness occurs from emboli to the central retinal artery of the eye

31. Transient Ischemic Attack (TIA)
Risk of stroke after a TIA is ~10-15% in the first 3 months with most events occurring in the first 2 days
Acute antiplatelet therapy is effective and recommended
Atherosclerotic risk factors:
Old age
Family history of thrombotic stroke DM
Tobacco smoking
dyslipidemia

32. Transient Ischemic Attack (TIA)
Other risk factors:
Prior stroke or TIA
Certain cardiac conditions
Oral contraceptives
Hypertension – most significant risk factor

33. Transient Ischemic Attack (TIA) Treatment
Antiplatelet agents
Aspirin:
Can prevent platelet aggregation
Acetylates cyclooxygenase whicg irreversibly inhibits the formation in platelets of thromboxane A2
Effect is permament and lasts for the usual 8-day life of the platelet
Also inhibits endothelial prostacyclin, and antiaggregating and vasodilating prostaglandin
mg/day is recommended for stroke prevention

34. Transient Ischemic Attack (TIA) Treatment
Antiplatelet agents
Clopidogrel:
Blocks the ADP receptor on platelets blocking the platelet aggregation
Dypiridamole:
Inhibits the uptake of adenosine by a variety of cells
Adenosine = inhibitor of aggregation
Also potentiates the anti aggregatory effects of prostacyclin and nitric oxide by inhibiting platelet phosphodiesterase
Prinicpal side effect is headache

35. Transient Ischemic Attack (TIA) Treatment
Anticoagulation therapies
The decision to use anticoagulation for primary prevention is based on risk factors (rheumatic heart disease, atrial fibrillation, and prosthetic valve implantation)

36. STROKE SYNDROMES

37. Middle Cerebral Artery

38. Middle Cerebral Artery
entire MCA is occluded at its origin :
contralateral hemiplegia, hemianesthesia, homonymous hemianopia, and a day or two of gaze preference to the ipsilateral side
Dysarthria is common because of facial weakness
global aphasia
anosognosia, constructional apraxia, and neglect