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Case Study

Ischemic Posterior Circulation Stroke Christopher Lewandowski, M.D. Residency Program Director Department of Emergency Medicine Henry Ford Hospital, Detroit, MI Sunitha Santhakumar, M.D. Department of Emergency Medicine Henry Ford Hospital, Detroit, MI. Case Study. HPI:

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Case Study

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  1. Ischemic Posterior Circulation Stroke Christopher Lewandowski, M.D.Residency Program Director Department of Emergency Medicine Henry Ford Hospital, Detroit, MI Sunitha Santhakumar, M.D.Department of Emergency Medicine Henry Ford Hospital, Detroit, MI

  2. Case Study • HPI: The patient is 41 y.o. male, with a past history of alcohol abuse, hypertension who presents to the ED with a chief complaint of right -sided weakness, slurred speech, and loss of balance. The symptoms began 90 minutes prior to arrival.

  3. Case Study • PMHx: • Alcohol Abuse, quit for 3 years • Hypertension • Seizures, Generalized, none for past 7 years • Medications • Dyazide • Social Hx • Smoking- 2 pack per day • ROS: Mild dizzy spells for the past 2 weeks, each lasting 5-10 minutes

  4. Case Study • Physical Exam: • BP- 149/79, P-100, RR-18, T-36.9 • A&Ox3 on presentation, later became stuporous • CN: dysarthria, pupils: R 3.5/ L 3.0 reactive • L facial droop, gaze palsy to the L • Motor: R arm and R leg weakness (3/5) • Sensory: Decreased to light touch and pinprick on R • Coordination: dysmetria on R (not out of proportion to weakness) • NIH Stroke Scale score = 14

  5. What does this patient have? • Differential Diagnosis • Stroke • Intracerebral Hemorrhage • Tumor • VBI • Migraine • Seizure

  6. Epidemiology • Stroke - leading cause of adult disability in the USA • 20% of strokes involve the vertebrobasilar arteries 20% of global cerebral blood flow is vertebrobasilar • Vertebrobasilar ischemia ranges from intermittent vascular insufficiency (VBI) to total basilar artery occlusion (BAO) • 20% - 60% with unfavorable outcome • Overall mortality 4%, BAO - 90% mortality

  7. Risk Factors: Uncontrollable • Age • Stroke risk doubles for every decade over 55 • Gender, Males - 1.3 x • Males have a higher risk, but females live longer, therefore there are more female stroke survivors • Heredity • African Americans - 2x • Family History • Previous stroke or TIA - 10x • Diabetes - 3x (even if well controlled)

  8. Risk Factors: Controllable • Hypertension - 6x (consistently >140/90) • Atrial Fibrillation - 6x • Smoking - 2x • Hypercholesterolemia > 200 • Heart Disease - 2x • Alcohol, (> 4oz/day) • Obesity • BMI > 30 • 35 inch waist in women, 40 inches in men

  9. Risk Factors Vertebrobasilar Ischemia • Risk factors for the Posterior circulation are the same as for the anterior circulation • Hypertension, diabetes mellitus, hyperlipidemia, and tobacco are especially important for the posterior circulation

  10. Posterior Circulation Stroke: Anatomy

  11. Posterior Circulation Stroke: Anatomy

  12. Atherosclerosis In situ thrombosis Often complete occlusion 90% mortality Embolization (20%-50%) Heart or proximal vessels May cause VBI Good prognosis Subclavian steal syndrome Symptoms brought on by arm exercise Trauma Especially in the young Vertebral artery dissection Lacunar (small vessel disease) Pathology

  13. Emergency Department Presentation • Prodrome very common • 60 % of patients with Basilar artery thrombosis • Stuttering or progressive onset of symptoms • 2 weeks prior to ED presentation

  14. Emergency Department Presentation • Prodromal Symptoms (in order of frequency) • Vertigo and Nausea (30%) • Headache, Neckache (20%) • Hemiparesis (10%) • Dysarthria, Diplopia (10%) • Hemianopia ( 6%) Ferbert, Stroke 1990

  15. Emergency Department Presentation • Clinical Findings: Depends on the syndrome • Range: asymptomatic to comatose • The 5 Ds: Dizziness, Diplopia, Dysarthria, Dysphagia, Dystaxia • Hallmarks: Crossed findings • Cranial nerve deficits - Ipsilateral • Motor / Sensory deficits - Contralateral

  16. Vertigo • Hallucination of movement of the patient or the environment, not associated with loss of consciousness • Visual, proprioceptive, and vestibular systems maintain position (Romberg test) • Semicircular canals connect to the vestibular nuclei in the brainstem via CN VIII • Vestibular nuclei connect to the cerebellum, MLF (eye movement) and the vestibulospinal tract

  17. Nystagmus • Nystagmus means “nodding” off (as in sleeping during this lecture, slow sleep phase with rapid correction) • Nystagmus is named for its fast component • Medial longitudinal fasciculus coordinates the ipsilateral medial rectus (CN III) and the contralateral lateral rectus (CN VI) • Inner ear provides symmetric resting discharge

  18. Nystagmus • Loss of input from one side leaves the other side unopposed • Unopposed stimulation causes a slow drift toward the diseased side • Cerebral cortex corrects for slow drift with a very rapid return toward a more normal position • The brainstem can compensate for asymmetric peripheral inputs leading to latency, fatigue, and habituation

  19. Vertebrobasilar Ischemia: Syndromes • VBI • Common term for TIAs of the vertebrobasilar system • Patients often asymptomatic in ED • Frequent episodes, especially as prodromal sx • Requires evaluation of etiology • Very rare to present as vertigo alone • Difficult to distinguish from other causes of dizziness

  20. Was this Patient’s Dizziness Central or Peripheral Central Peripheral Intensity Mild Severe Tinnitis Rare Common CN findings Frequent None Nystagmus: Visual fixation No inhibition Inhibits Horizontorotary Rare Common Latency None 3-40 sec Fatigue None yes

  21. Posterior Circulation Stroke: Syndromes • VBI, brainstem TIAs: • Occur over days-weeks • Intermittent fluctuating brainstem sx • Dizziness plus cranial nerve symptoms • Rarely dizziness alone

  22. Vertebrobasilar Ischemia: Syndromes • Branch artery occlusions • Produce a specific stroke syndrome for each artery • Longer and circumfrential arteries • Small penetrating branches supplying midline structures and causing lacunar syndromes • Characterized by the 5Ds and crossed findings • The severity of the stroke depends on the collateral blood flow and the location of the occlusion

  23. Posterior Circulation Stroke: Syndromes

  24. Vertebrobasilar Ischemia: Syndromes • Basilar artery occlusion • 75% with prodromal symptoms • 63% with gradual and progressive onset • Can produce a locked-in syndrome • Awake, quadriplegia, bilateral facial and oropharyngeal palsy, preserved vertical gaze • May present comatose if reticular activating system is involved

  25. Emergency Department Diagnosis • History • Prodrome • Dizziness • Physical Exam, • Blood pressure in both arms • Diagnostic Studies • Blood tests,CXR, EKG • Imaging

  26. Confirm the Diagnosis (Emergent) CT Scan MRI, MRA, DWI TCD Angiography (DSA) Evaluation of Stroke Etiology (Inpatient) MRA / Angiography Echo / TEE TCD Carotid Doppler Emergency Department Diagnosis

  27. Emergency Department Evaluation • CT scan - head, noncontrast • Necessary to rule out intracerebral hemorrhage • Most sensitive test for ICH • Poor for posterior fossa visualization • Bone artifact • Can pick up Basilar artery thrombosis • Highly specific sign, very low sensitivity • CT Angiography (spiral CT) • Reliably assesses basilar artery patency, inconclusive in patients with advanced arterial calcification

  28. Case Study: CT Scan

  29. Baseline CT scan

  30. Emergency Department Evaluation • MRI - long scan times, unavailable, access to patient is poor • Standard MRI, not reliable for ICH in first hours • Major advantage is Posterior Fossa imaging • MR Angiography -reliable evaluation of arteries for VBI, BAO • DWI - Diffusion weighted imaging demonstrates infarcted tissue, this is not a contraindication to thrombolysis

  31. MRI-DWI in the posterior fossa

  32. Emergency Department Evaluation • TCD • Assesses flow through Vertebrobasilar system • Limited in BAO • Patient anatomy, penetration to distal BA difficult • Brandt: TCD diagnostic in 7 of 19 patients with suspected BAO, 2 of 19 false negatives • Low sensitivity for BAO, not useful in ED

  33. Emergency Department Evaluation • Digital subtraction angiography • Gold Standard for diagnosis of BAO • Time consuming, expensive, invasive • Requires patient cooperation, anesthesia • Allows for intra-arterial intervention • Thrombolysis, angioplasty

  34. Emergency Department Management • Stabilization • Ensure oxygenation and ventilation • Optimize cerebral blood flow by managing the blood pressure and hydration carefully, as autoregulation lost, ischemic areas become perfusion dependant • Avoid glucose, avoid hypotension, treat fevers aggressively • Evaluate for anticoagulation or thrombolysis

  35. Emergency Department Management • Conservative Treatment • Antiplatelet and Antithrombotic • Thrombolytic Treatment • Intravenous: within 3 hours symptom onset and the patient meets all treatment criteria • Intra-Arterial Therapy: infusion of thrombolytic agent into vessel or clot within 24 hours of onset of symptoms

  36. Posterior Circulation Stroke: Treatment • Conservative Treatment • Antiplatelet and Anti thrombotic Therapy • Uncontrolled, Retrospective Studies , 1950s & 1960s • Compared to historical controls, patients treated with heparin had lower mortality (8-15% vs. 40-60%) • Stopped progression of VBI to infarction • TOAST Trial • No evidence to support heparinization in acute stroke

  37. Posterior Circulation Stroke: Treatment • Intravenous Thrombolysis • NINDS rt-PA Acute Stroke Trial • t-PA approved within 3 hours of symptom onset • Few posterior circulation strokes

  38. Posterior Circulation Stroke: Treatment • Intra-arterial Thrombolysis • No randomized controlled trials completed • Multiple small series and reports • Results (Over 200 patients treated) • Mortality 20-60% , assoc. with lack of recanalization • Favorable outcomes in 25%-60% • ICH rate low, 0-15%

  39. Posterior Circulation Stroke Future Treatment • Intra-arterial Thrombolysis • Superselective approach, micro-catheters • Angioplasty • Angio-jet

  40. What is the prognosis for this patient ? • All Posterior Circulation Strokes • New England Medical Center Posterior Circulation Stroke Registry: • Mortality = 4% • Minor or no Disability = 79% • Locked In Syndrome (Basilar artery occlusion) • Mortality > 90% • How do you know if a patient will progress to locked-in syndrome ? Observation

  41. Case Study: Outcome • The patient mental status deteriorated, repeat NIH-SS score was 22 • He received intravenous thrombolysis • He had significant early improvement but without complete resolution of symptoms • On day 4, the NIH - SS score was 10 • MRA : L sup. cerebellar art. and R&L Ant-Inf cerebellar arteries were non-visualized, • Cardiac evaluation was negative • He was discharged on Coumadin to Rehab

  42. Case Study: MRI - DWI<12 Hours 4 Days

  43. Summary • Posterior Circulation Strokes are characterized by the 5D’s and crossed findings • Maintain a high index of suspicion for prodromal symptoms - vertigo with CN sx • The locked-in syndrome consists of quadriplegia, bilateral facial and oropharyngeal palsy; but preservation of cortical function and vertical gaze

  44. Summary • The prognosis for vertebrobasilar ischemia is generally good, except for locked-in syndrome (basilar artery occlusion) • Treatment consists of conservative therapy (aspirin and heparin) or IV thrombolysis (<3 hrs) or IA thrombolysis (up to 24 hours)

  45. Question 1 All of the following are posterior circulation syndromes except: • Ipsilateral CN III palsy with contralateral hemiplegia B) Ipsolateral facial palsy with contralateral hemiplegia C) Hemiaplegia and hemisensory loss of the face arm and leg on one side of the body D) Ipsilateral ataxia and Horner”s with contralateral loss of pain and temperature sensation

  46. Question 2 Locked-in Syndrome consists of: A) Coma with quadriplegia B) Bilateral upper extremity weakness greater than lower extremity weakness C) Quadriplegia, bilateral facial and oropharyngeal palsy but preservation of cortical function and vertical gaze D) cranial nerve findings contralateral to motor and sensory findings

  47. Question 3 Vertigo of central origin is: A)Generally severe and sudden in onset B) Is a very common isolated prodromal symptom of VBI C) Is often associated with tinnitus D) Fatigues easily E)Is generally associated with cranial nerve findings

  48. Question 4 Proven therapy for posterior circulation stroke includes: A) Heparin B) Low molecular weight heparin C) IV thrombolysis D) Intra-arterial regional thrombolysis E) Intra-arterial local thrombolysis

  49. Question 5 Overall mortality for posterior circulation strokes is: A) < 5% B) 20% C) 40% D) 70% E) > 90%

  50. Question 6 Mortality for Locked-in Syndrome is: A) < 5% B) 20% C) 40% D) 70% E) > 90%

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