Intro to Stroke

• A stroke is a sudden onset of neurologic signs and symptoms, resulting from a disturbance of blood flow to the brain.
• Age over 55 is a non-modifiable risk factor for stroke.
• African-Americans have an increased risk of stroke.
• Males have an increased risk for stroke.
• Family history is a nonmodifiable risk factor for stroke.
• A prior stroke, transient ischemic attack, or MI is a non-modifiable risk factor for stroke.
• 80% of strokes are the result of a modifiable risk factor.
• The two types of strokes are hemorrhagic and ischemic.
• In a hemorrhagic stroke, blood leaks into brain tissue.
• In an ischemic stroke, a clot stops blood supply to an area of the brain.
• Ischemic strokes result in low perfusion pressure and a lack of cerebral blood flow.
• 87% of strokes are ischemic.
• Ischemic strokes are caused by thrombosis or embolus.
• Thrombotic clots are within the brain. The formation or development of the clot occurred within the cerebral arteries or branches.
• Thrombotic clots are typically the result of atherosclerosis.
• Embolic clots travel from elsewhere in the body. It formed somewhere, broke off, and traveled to the cerebral vasculature.
• Embolic clots are typically the result of cardiovascular disease.
• Hemorrhagic strokes are caused by intracerebral hemorrhages, subarachnoid hemorrhages, or arteriovenous malformation.
• Intracerebral hemorrhages occur within the brain tissue.
• Subarachnoid hemorrhages are primarily aneurysms that occur within the subarachnoid space.
• Arteriovenous malformation is a congenital pathology where the vessels in the brain do not form correctly at both. This commonly causes strokes in the pediatric population.
• The infarct core is the area of cell death.
• Penumbra is the area around the infarct core that may be killed depending on the quickness of medical intervention.
• A transient ischemic attack is a temporary disruption of blood flow.
• TIAs are a precursor to stroke and MI.
• 40% of people who have a TIA will have a stroke.
• The most common cause of TIA is reduced perfusion due to arrhythmias.
• NIHSS stroke scale

  A) no stroke

  B) minor stroke

  C) moderate stroke

  D) moderate to severe

  E) severe stroke

  
• The seven items tested in the NIHSS are level of consciousness, gaze/vision, motor, ataxia, sensory, language, and extinction.
• CT scans identify large structures. In the acute phase, bleeding and hemorrhagic transformation is visible.
• CT scans are used to rule of hemorrhagic strokes.
• CT scans detect in 3-5 days, and allow visualization of edema in 3 days.
• MRI is more sensitive, but typically done after a CT scan.
• MRI will detect infarct in 2-6 hours and ischemia within 30 minutes.
• MRI's are used to determine where an ischemic stroke damaged.
• Patients who arrive within 3 hours of symptom onset with an ischemic stroke are given tPA.
• Patients who recieve tPA are 33% more likely to recover from their stroke.
• In order to give tPA, you must have consent from the patient or a family member.
• The last known well time has to be within 3 hours of hospital arrival in order to receive tPA.
• The goals of medical management of a stroke acutely are to stop the bleeding, reperfuse areas, and identify the cause.