Medical and Neurobehavioral Variables

Question 1

What is a Stroke?

Answer 1

• Neurological changes lasting more than 24 hours
• Caused by an interruption in the blood supply to a part of the brain.
• If the blood flow ceases for an extended period of time, the cerebral tissues involved die causing permanent neurological deficits.

Question 2

Stroke Statistics

Answer 2

• No. 3 cause of death in the U.S.
• Stroke kills more than 160,000 Americans each year
• On average, every 53 seconds, someone in the US experiences a stroke
• Every 3.1 mintues someone dies of a stroke
• Stroke risk increases with age. For each decade after age 55, the risk of stroke doubles.
• 72% of all strokes occur in people over the age of 65.

Question 3

African Americans and Stroke

Answer 3

• Incidence is nearly double that of Caucasians
• AA suffer more extensive physical impairments
• High incidence of risk factors for stroke:
• Hypertension (high blood pressure)
• Diabetes
• Obesity
• Smoking
• sickle cell anemia

Question 4

Region of the brain and stroke

Answer 4

• Cerebellar Stroke: the cerebellum controls many of our reflexes and much of our balance and coordination.
• Brain Stem Stroke: The brain stem is the area of the brain that controls all of our involuntary “life support” functions as well as abilities such as eye movements, hearing, speech, and swallowing.

Question 5

Signs and Symptoms of Stroke

Answer 5

• Sudden numbness or weakeness of the face, arm, or leg, especially on one side of the body.
• Sudden confusion, trouble speaking, or understanding
• Sudden trouble seeing in one or both eyes
• Sudedn trouble walking, dizziness, loss of balance or coordination
• Sudden, severe headache with no known cause.

Question 6

Transient Ischemic Attacks (TIAs)

Answer 6

• A stroke-like event lasting mintues, or hours, that occurs when the brain is deprived of oxygen-rich blood temporarily, but in which the effects wear off completely after the blood-flow returns.
• TIA’s do not result in permanent brain damage
• TIA is serious and too often ignored.
• More than 1/3 of people will go on to have an actual stroke.
• 5% will occur within 1 month
• 12% will occur within 1 year
• 20% will occur within 2 years
• 25% will occur within 3 years

Question 7

Cerebral Circulation Review

Answer 7

• Brain derives its arterial supply from carotid and vertebral arteries.
• Carotid and vertebral arteries begin extracranially
• Internal carotid arteries and brances supply anterior 2/3 of cerebral hemispheres.
• Vertebral and basilar artiers supply porterior and medial regions of hemispheres, brainstem, cerebellum and cervical spinal cord.
• The two vertebral artiers and the basilar artery are sometimes together called the veretebrobasilar system, which supplies blood to the posterior part of circle of Willis.

Question 8

Ischemic vs. hemorrhagic

Answer 8

Ischemic: clot, occlusion (most common) 80-84%
-caused by blockage of atery resulting in reduction of blood flow and cell death.
CT scan negative until a few days post stroke then hypodense area- indicates infarction.
embolism- when a blood clot travels
thrombotic- build up of fatty subtances in arterial wall. provide a way of stopping the blood from getting to the brain.

Hemorrhagic: Bleed, rupture (bleeding around or into the brain)
blood in tissue of brain and bleeding around and into the brain. As blood gushes out it misplaces material.
AVM- congential genetic malformation. Twisting of vessicles, blows spontaneously causing a hemirrhagic stroke.

Question 9

Mechanisms that underlie stroke

Answer 9

Hemmorhage- intensive care

• Rupture
• Hypertension- high blood pressure is wear and tear of arteries over time. Arteries weaken and can produce vulnerability for a bleed.
• Aneurysm- ballooning or weakness on wall
• Medically more serious
• better recovery overall
• blood on the brain will make them disordered, but once it goes back the brain is okay.

Ischemia-
-Occlusion
-TIA
-Thrombosis- atherosclerosis in cerebral arteries is a process that occurs over decades. in thrombitc stroke artery narrows to point of obstruction.
-lacunar- occur in old age. they accummulate. not one single stroke. overtime small vessles occluding. looks like a dementia rather than a stroke.
-Embolus- a clot travels from source outside of brain. encounters vessle with lumen narrow enough to block its passage. clot lodges there, blocking blood flow. most common source-heart. common conditions, atrial fibrillation, valvular disease, ventricular thrombi, atherosclerosis of the proximal aorta.
-Thromboembolic
-Vasculitis- swelloing of vessle due to bacteria or inflammation.
-Key treatment for ischemic strokes is tissue plasminogen activator (tPA). tPA is a clost-busting agent that is injected into the blood stream to break up the blockage to blood flow. Must be given 3 hours post onset of symptoms. Patients must meet strict criteria to elimante risk fo hemirrhage.
Carotid endarterectomy- atery is surgerically open to remove bloackage, or catherter is used.