Diagnosis and Management of acute ischemic stroke

1. Diagnosis and Management of acute ischemic stroke

2. Stroke-Definition • Acute loss of vascular perfusion to a region of the brain resulting in ischemia and loss of neurologic function and/or tissue destruction • Can be hemorrhagic or ischemic in etiology

3. Stroke definition continued • Neurologic dysfunction can take the form of a deficit in any neurologic domain including motor, sensory or cognitive. • Typical symptoms can include weakness, incoordination, visual loss, language (production or comprehension).

4. Stroke pathophysiology • Ischemic: embolic, thrombotic, vasculitic or hypoperfusion, arterial dissection. • Hemorrhagic: intraparenchymal or subarachnoid.

5. Epidemiology • In U.S. 795,000 strokes per year, 625,000 are ischemic • There are currently 4.4 million stroke survivors in the U.S. • 3rd leading cause of death in U.S. and in other industrialized countries.

6. Epidemiology continued • Number one cause of disability in the U.S. -26% will need assistance with ADLs. -30% will need walking assistance -26% will require admission to long term care facility

7. Epidemiology • Stroke occurs in all age groups including children • 75% of all stroke occur in the age 65 and older group • The age adjusted risk of death due to stroke in blacks is 1.49 compared with whites.

8. Clinical presentation • Acute neurologic deficit • Sudden hemiparesis/hemiplegia, loss of language function (receptive or expressive), dysarthria, loss of vision in one or both eyes, sudden ataxia, hemibody numbness, vertigo, diplopia, clumsiness, sudden onset headache (thunderclap)

9. Important history to obtain HPI: • Absolute onset of symptoms • Presence of progressing or “stuttering symptoms” • Attempt to localize with questions to isolate particular vascular territory: Anterior versus posterior, left or right

10. Pertinent PMH • Assessment of risk factors: DM, HTN, HLP, coagulopathies, A-fib, CHF, previous stroke, cardiac arrhythmias, cancer, pregnancy, recent surgeries, recent TIA, migraine or other HA hx • Medications: anticoagulants, antihypertensives, antiplatelet agents. • SHx: tobacco, ETOH, drug use, supplements

11. Pertinent family history • Stroke, coagulopathies, DM, rheumatologic conditions (young patients).

12. Ischemic Stroke classification • Anatomic: Anterior (carotid) versus posterior (vertebrobasilar) circulation, and dominent versus non-dominant hemisphere. • Large vessel versus small vessel (lacunar) • Embolic versus thrombotic.

13. MCA infarct

14. Lacunar strokes

15. Anatomy of a stroke

16. Anterior circulation

17. Anterior circulation symptoms • Monocular visual loss (Amaurosis fugax) • Language dysfunction: aphasia • Hemimotor: Face/arm>leg, leg>face/arm • Hemisensory symptoms • Apraxia • Hemivisual symptoms (also posterior circulation)

18. Localizing anterior circulation strokes

19. Posterior circulation symptoms • Vertigo • Ataxia • Isolated Hemimotor dysfunction: Arm=leg=face (Pontine stroke). • Diplopia • Dysarthria • Hiccups • Hearing loss

20. Diagnosis • Based on history of acute onset neurologic deficit in localizable vascular territory • Associated objective clinical neurologic exam findings • Supported with specific neuro-imaging CT and MRI findings

21. Diagnosis Must localize process before creating differential diagnosis and ordering imaging

22. Important neurologic exam findings • Level of consciousness, orientation **Usually preserved with most focal strokes** • Higher cortical functions: Language comprehension and fluency, naming, praxis, left-right orientation, calculation, neglect

23. Neurologic findings • Cranial nerves: Pupils and extraocular movements: affected by brainstem involvement • Vision: Monocular versus binocular, visual field testing. • Facial movement: upper versus lower face involvement: important in differentiating brainstem (nuclear 7th) versus central 7th palsy • Swallowing/gag

24. Neurologic Exam findings • Motor: weakness-pyramidal pattern tone: increased or decreased posturing, pronator drift • Sensory: negative sensory symptoms-central pattern • Reflexes: hyper-reflexia, Babinksi sign • Gait: hemiparetic, apraxic or ataxic

25. Initial management • ABCs • O2 • IV fluids

26. Initial Diagnostic testing • Vital signs including temperature • Labs: Glucose, coags, chemistry, CBC • EKG • Non contrast Head CT • Cardiac enzymes

27. Head CT pros and cons Pros • Can be obtained quickly • Sensitive to identifying intracranial acute blood Cons • Ischemic changes may not show for 6+ hours • Less sensitive to processes in posterior fossa

31. Ischemic stroke management • Determine level of impairment, NIH stroke scale can be helpful • Antiplatelet therapy or tPA • Blood pressure management, maintain MAP 100-130, SBP <220, DBP<120 use labetalol IVP, enalaprilat IVP or Nitroprusside gtt if needed.

32. Ischemic stroke management • Determine appropriateness for IV tPA or intravascular intervention (IA tPA, mechanical clot removal) • Recent recommendations made for expanding IV tPA window to 4.5 hours but tPA should still be administered ideally within 1 hour of patient presentation.

33. Additional stroke management • Admission to telemetry bed • Continued IV hydration • DVT prevention • NPO until speech pathology eval if indicated. • Evaluate for signs of co-existent infection • Statin therapy?

34. Additional Evaluations • MRI brain with DWI, MR angiography • Carotid duplex neck for anterior circulation strokes • MRA neck for posterior circulation strokes • CT angiography- sometimes indicated • Echocardiogram +/- bubble study (in young) • Conventional angiography rarely indicated

35. MRI-DWI

36. MRI-DWI

37. DWI and PWI (perfusion weighted)

38. Additional evaluations • RPR, homocysteine, fasting lipid profile, lipoprotein a, ESR or CRP • Rheumatologic studies and hypercoagulation panel if indicated (stroke in young)

39. Stroke complications • Aspiration/pneumonia • DVTs • Falls • Depression • Secondary hemorrhage • Increased intracranial pressure

40. Stroke prognosis • In Framingham and Rochester studies the 30 day mortality after stroke was 19%. The one year survival rate was 77% • In the Framingham heart study, 31% of stroke survivors needed help caring for themselves, 20% needed help ambulating and 71% had some impairment in vocational capacity.

41. What about TIAs • These represent transient focal interruptions in cerebral blood flow and can be embolic or thrombotic. • TIAs confer a 10% risk of stroke in 30 days. • Half of all strokes that follow a TIA occur within the first 48 hours.

42. Work-up of TIAs • The diagnosis of a TIA often rests on a clinical history of a localizable focal vascular event in the context of known stroke risk factors. • These should be evaluated aggressively with hospital admission, telemetry, and a search for a embolic source or other predisposition for an ischemic stroke.

43. Questions?