1. Pathophysiology of Stroke Wanda Lovitz, APRN

2. Objectives: Stroke
Describe the risk factors, early identification and treatment associated with acute brain attack.
Differentiate the pathologies of ischemic stroke, hemorrhagic stroke, lacunar stroke, and transient ischemic attack.
Compare the arrhythmias atrial fibrillation and ventricular fibrillation.
Cite the most common causes of hemorrhagic stroke.
Describe the clinical manifestations associated with subarachnoid hemorrhage.
State the progression of sensory and motor deficits, and speech and language problems that occur as a result of stroke

3. Stroke (Brain Attack)
Definition
An acute focal neurologic deficit from a vascular disorder that injures brain tissue and results in deficits as well as causing motor & sensory, and language and speech problems
Also known as a cerebral vascular accident (CVA) or“ brain attack”
About 600 people admitted to UK yearly with stroke, 25% under the age of 55
3rd leading cause of death
#1 cause of nursing home admission

4. Primary Injury vs Secondary Injury
Primary Injury = SUDDEN cessation of blood flow to an area of brain tissue resulting in IRREVERSIBLE ISCHEMIA to some cells
Secondary Injury = development of further neurologic damage, may progress over days or weeks
TIME IS TISSUE!

5. Risk Factors Associated with Stroke
Age: Increases with age (increases 1%/year between 65-74)
Also can see stroke in infants & children
Gender: males > females
Race: African-Americans > Caucasians (60% greater risk) Also Asians have increased risk
Hx: Heart disease, HTN, smoking, high cholesterol levels, DM

6. What is a thrombus? Pathological thrombus = THROMBOSIS
Is NORMAL in cases of injury
ABNORMAL :
a blood clot that forms in a blood vessel
may be arterial or venous
Pathological thrombus = THROMBOSIS
May be caused by fatty deposits that build up in arteries
Damage to the endotheilum (often r/t poorly controlled HTN) fosters buildup of fatty deposits and cholesterol
Body responds to the vessel wall injury by forming plaque which can rupture and form clots

7. Atherosclerosis: Hyperlipidemia/High cholesterol

8. Common areas in the brain for stroke
Middle Cerebral Artery (MCA)
2. Basilar Artery
3. Posterior Cerebral Artery
The deficits the person experiences is determined by the LOCATION of the infarct

9. RIGHT sided stroke vs LEFT sided stroke
Hemiparesis vs Hemiplegia
weakness paralysis

10. Cerebral INFARCTION
Infarcted tissue is “DEAD” and the function of the organ is altered.
The tissue is not responsive to any treatment to restore its function.

11. Cerebral ISCHEMIA Ischemic tissue is POTENTIALLY ‘salvageable’
Current treatment is directed toward restoring blood flow to injured tissue
“TIME IS TISSUE”
Angiogram showing a
blocked cerebral artery

12. Main types of Stroke ISCHEMIC – HEMORRHAGIC –
caused by an INTERRUPTION in blood flow
HEMORRHAGIC –
caused BY BLEEDING into brain tissue from a ruptured cerebral vessel

13. Stroke Categories 1. Ischemic (slow event)
(70-80% of all strokes)
Thrombotic
Embolic
2.Hemorrhagic (fast, sudden event)
Usually occurs as result of rupture of blood vessel from HTN, aneurysm, or head injury

14. Think Supply and Demand Crisis!
Ischemic Stroke
Think Supply and Demand Crisis!
ISCHEMIA – results in greatly reduced or interrupted blood flow in a vessel
A THROMBUS OR EMBOLUS is PARTIALLY blocking the blood supply.

15. Ischemic Penumbra TIME IS TISSUE! Stroke (brain)= 3H “Bull’s Eye
Central core of dead or infarcted tissue
Ischemic Penumbra
Small blood flow
Cells maintain some integrity
?? Salvageable
Thrombolytics
Clot busting drugs may be effective during penumbra window
Coronary (heart) = 6H
Stroke (brain)= 3H
TIME IS TISSUE!

16. Ischemic Penumbra Ischemic zone = greatly 70-80% of all strokes are
ISCHEMIC strokes. And the
majority of ischemic strokes
are d/t a thrombus.
Ischemic zone = greatly
reduced blood flow
POTENTIAL to salvage tissue

17. Ischemic Penumbra Goal of tx
Cells in the penumbra receive a SMALL amount of blood flow allowing some metabolic function
The injured cells undergo ELECTRICAL FAILURE
Goal of tx
MINIMIZE damage to penumbra
Support cells –
Oxygen
Improved circulation with “clot busting” thrombolytics drugs

18. What is the Penumbra device?
The Penumbra is a recently approved device (2008) that can be used to “vacuum” out the cerebral blood clot
A tiny vacuum cleaner for the brain
Can be tried up to 8 hours after a stroke strikes or after failure of thrombolytic therapy
FDA approved 12/08

19. Infarction/Penumbra
If thrombus is large enough to completely occlude vessel
then INFARCTION occurs distal to the occlusion.
A partial occlusion would result in ISCHEMIA.

20. Alexa Eleanor Ehlers Went to school in Argyle, TX (North Texas)
Born in Glenwood Springs, CO (October 2, 1994) & my family lives there again now.
I live on and manage my family’s farm, Clear View Equestrian Center, behind Keeneland.
I have one dog, three cats, and 5 horses of my own.
I have represented the U.S. in international team competitions here in the States four times, winning team gold and bronze, and have represented the U.S. in international team competition once in Australia, winning team bronze.
Last, but not least, I’m blessed with an amazing family that loves to travel.
My mom, Stacy; father, Jeff; older sister, Kelsey (25); older brother, Robbie (24)

21. Types of Ischemic Stroke
Small Vessel (Lacunar)
small vessels deep in the brain affected
Large Vessel (Thrombotic)
r/t hyperlipidemia with unstable plaque
Cardiogenic (Embolic)
Clot moves from the heart and lodges in a vessel in the brain

22. Small Vessel (LACUNAR) Stroke (20% of strokes)
KEY CONCEPTS
TINY and in DEEP brain structures
basal ganglia or pons
Cause: occlusion of small branches of cerebral arteries
Form small cavities “lacunae”
Specific manifestations based on location of injury
Generally less deficits
Diagnosed: by symptomatology
Usually too small to be seen on CT scan

23. Large Vessel (THROMBOTIC) Stroke
Key Concepts:
Most common type of ischemic stroke
Location: arterial bifurcations
Affected part of brain: cortex
Common deficits:
Aphasia
Neglect
Visual problems
Event is NOT associated with activity
Effects: localized (focal) distal to blockage.

24. Cardiogenic (Embolic) Stroke
Key Concepts
Most common location: middle cerebral artery (MCA)
A MOVING blood clot travels from its origin (heart/cardiogenic) to the brain
Usual location
Lodge -- larger proximal cerebral vessels often at bifurcations
RAPID onset of symptoms.

25. Cardiogenic Embolic Stroke: Predisposing Conditions
Atrial Fibrillation (AF)
Rheumatic Heart Disease (RHD)
Recent Myocardial Infarction (MI)
Bacterial Endocarditis

26. Normal heart complex on EKG

27. What is Atrial Fibrillation?
Irregular heart rate
Atria are “quivering” instead of contracting regularly
fibrillation waves instead of a single “P” wave before each QRS
Results in IRREGULAR ventricular contraction
Is the most common cause of irregular heart beat

28. What is Ventricular Fibrillation?
The MOST SERIOUS cardiac arrhythmia
Ventricles are not contracting in a coordinated fashion, just ‘fibrillating’ rapidly
No cardiac output
The patient is clinically dead!
Must be ‘DEFIBRILLATED’ in order to restore cardiac rhythm

29. Atrial fibrillation rhythm strip
Fibrillation waves
Normal “P” wave
Note irregularity and absence of “P” waves. Instead have
“fibrillation” waves.
No “p” wave
Fibrillation waves
Irregular R – R interval
Normal sinus rhtthm

30. Atrial fibrillation vs ventricular fibrillation What does the person LOOK LIKE?
is NOT life threatening
when controlled (HR less than 100)
Will see CO, palpitations
 risk CHF,CVA
Generally is
treatable and not
deadly.
Ventricular fibrillation is
a LETHAL arrhythmia = cardiac arrest
Will see unresponsiveness
No pulse, no B/P
Person will die if
a normal rhythm is not
quickly restored

31. What is a TIA? TRANSIENT ischemic attack
Key concepts
Focal event, due to ischemia
TRANSIENT - Sx relieved by 24 hours post onset!
Think of it as “angina of the brain!”
A WARNING SIGN OF IMPENDING STROKE
Is A TEMPORARY disturbance and IS REVERSIBLE
Is a “mini-stroke”
Area of penumbra, but no infarcted tissue

32. What is a Hemorrhagic Stroke?
Key Concepts
Most common cause of FATAL STROKE, why?
Causes cerebral edema
Causes compression of brain contents
Causes spasm of adjacent blood vessels
Usually occurs with ACTIVITY
 BP and pressure in cerebral vessels

33. Hemorrhagic Stroke Most of the brain is affected here.
Worst headache of my life!!!
Most of the brain is
affected here.
Would see death or severe brain
dysfunction and have a sudden
onset

34. Underlying Causes of Hemorrhagic Stroke
Cerebral Aneurysms
Subarachnoid hemorrhage (SAH)
Trauma
Tumor-related erosions
Arteriovenous malformations (AVM) (2%)
Poorly controlled HTN (systolic  200)

35. Hemorrhagic stroke: Cerebral Aneurysms
BERRY aneurysms
Tend to enlarge over time, weakening vessel wall increasing chance of rupture
Rupture causes hemorrhagic stroke
If > 10 mm in size have 50% chance of bleeding per year.
Primary site is the
Circle of Willis

36. Cerebral Aneurysms Rupture is associated with acute increase in ICP
e.g., straining, sexual activity, etc.

37. Aneurysmal Subarachnoid Hemorrhage (SAH) – a common cause of hemorrhagic stroke
What is it?
Bleeding into the subarachnoid space caused by a cerebral aneurysm
An aneurysm is a bulge at the site of a localized weakness in the wall of an arterial vessel

38. SAH Factoids Usual age: 30-60 years Mortality/morbidity = high
About 50% die within 3 months
½ of survivors have serious disabilities
Bleeding follows along CSF channels, so SAH extends rapidly over a large area

39. “Classic” Manifestations of SAH
Sudden onset of SEVERE headache
“Worse headache ever!”
Deteriorating LOC – Rapid
Meningeal irritation
Nuchal rigidity
Photophobia
Cranial nerve deficits (CN II & III most often –optic& oculomotor)
Visual disturbances, photophobia, cardinal fields of gage affected
Increased ICP

40. Complications of SAH Rebleeding Vasospasm Watch 1st 24 hours! Seizures
Watch for in 3 to 10 days post bleed
Vasospasm with ischemia
Intracranial hemorrhage

41. Diagnositic tests: SAH
Lumbar Puncture shows:
Blood in the CSF

42. Other causes of hemorrhagic stroke
Brain tumor
AV Malformation

43. Arteriovenous malformations (AVM)
A tangle of abnormal arteries and veins linked by one or more fistulas
Lack a capillary bed and have a deficient muscular layer
Predisposed to rupture and hemorrhage

44. You Tube Video
ACT “FAST”

45. Diagnosis of Stroke Hx, PE Imaging Lumbar Puncture CT MRI Angiography
CT scan
Hx, PE
Lumbar Puncture
Imaging CT
Shows hemorrhage or large infarct
Does not pick up new ischemic damage
MRI
Best for new ischemic problems or small infarcts
Angiography
Locates exact site of abnormality – involves use of contrast dye
MRI

46. CT is less sensitive than an MRI in detecting stroke

47. Key Concepts: Clinical Manifestations of Acute Stroke (most common with ischemic)
Symptoms depend on affected cerebral artery
Symptoms occur:
Relatively rapidly, and are usually focal and unilateral
Most common Sx:
Weakness of face, arm & possibly one leg (hemiparesis) = motor deficits
Weakness may be replaced by hyperflexion & spasticity

48. Courtney Watson

49. Clinical Manifestations Common with Stroke
Watch the You Tube Video “ Effects of Stroke”

50. Functional effect of stroke

51. Stroke Presentation Affected Artery Signs Internal carotid artery
Unilateral blindness
Contralateral hemiplegia, hemianopia
Aphasia with left hemisphere
Middle cerebral artery
Communication, cognition difficulties
Contralateral hemiplegia or hemiparesis
Anterior cerebral artery
Emotional lability, confusion, amnesia, personality changes
Urinary incontinence
Posterior cerebral artery
Cortical blindness
Memory deficts
Hemianopia – bilaterally symmetric loss of vision in half of the visual fields

52. Effects of Stroke: Movement Issues (motor impairment)
Movement Problems
Hemiparesis/hemiplegia
Mild-profound weakness on CONTRALATERAL side
Clumsiness in fine motor skills
Facial droop
Apraxia (inability to carry out learned activity)
Verbal apraxia….person cannot say words they intend to say
Foot drop
Outward rotation of leg
Initial flaccidity followed by spasticity

53. Effects of Stroke: PERCEPTION issues
Perception Problems
Unilateral neglect (d/t inability to analyze/interpret incoming sensory information
May deny illness or deny one half of body and environment on affected side)
Flat affect
Hemianopsia/visual problems
 awareness of one side of the body
Inability to distinguish directional concepts (up/down)

54. Effects of Stroke: SENSATION issues
Sensation Problems
 awareness of touch/temperature
 proprioception
Balance problems
Vertigo

55. Effects of Stroke: LANGUAGE problems
Aphasia/dysphasia (some degree of inability to speak or to comprehend)
Dysphasia (impairment of speech)
Dysarthria (imperfect speech sounds)
Word finding problems
Incorrect use of verbs or nouns
Expressive aphasia (comprehension intact but cannot express)
Receptive aphasia (can communicate but cannot comprehend what is being said ”can’t receive”

56. Consequences
Aphasia

57. Effects of Stroke: VISUAL problems
Visual disturbances
Contralateral field blindness
Homonymous
Hemianopsia

58. Effects of Stroke: Movement Issues
Flaccidity – contralateral side
Spasticity – within 6 weeks
What will happen to the muscles?

59. Effects of Stroke: MEMORY and BEHAVIORAL Issues
Memory problems
Most memory problems are with remembering names, words, objects
Behavioral problems
 emotional response
Judgment is usually intact
May underestimate own abilities
Slow reaction times
Hesitant and cautious
May be apathetic, confused, disoriented

60. FAST……. Recognizing the symptoms of a stroke

61. Treatment

62. Be a good nurse…. Know how to recognize a stroke
Act FAST….Know how to assess for stroke
80% of strokes are preventable
500 thousand Americans will have their first stroke this year
There is a 4 times greater risk of stroke for women who smoke and take the Pill

63. The End