Welcome back to our continued discussion about neurological disorders. In this lecture, we will be focusing on types of stroke and stroke clinical manifestations. Cerebrovascular disorders are an umbrella term that refers to a functional abnormality of the central nervous system that occurs when the blood supply to the brain is disrupted.
Stroke is the primary cerebrovascular disorder in the United States and it is currently the fifth leading cause of death and it is still a leading cause of serious long-term disability hundreds of thousands of people each year experience experience a stroke in the United States about 7 million people who have survived a stroke are alive today and the financial impact of that is profound it is in the the billions. You may also hear stroke referred to as a cerebrovascular accident or a brain attack. So what is a stroke?
A stroke is inadequate blood flow to the brain resulting in death of brain cells. Depending on what part of the brain tissue is dead, those are the symptoms that will be seen in a stroke. Strokes can be divided into two major categories.
Ischemic, which are approximately 85% of all strokes, in which vascular occlusion and significant hypoperfusion occur. And hemorrhagic, which makes up approximately 15% of all strokes, in which there is an extravasation of blood into the brain or sub- arachnoid space. Although there are some similarities between the two types of stroke, differences exist in etiology, pathophysiology, medical and surgical management, and also nursing care.
There are different types of ischemic stroke. Remember, an ischemic stroke results from inadequate blood flow to the brain. from a partial or complete occlusion of an artery.
And these account for approximately 85% of all strokes. But they are further divided into thrombotic and embolic strokes. Thrombotic strokes are your more common. They account for about 60% of the ischemic strokes. These occur from injury to a blood vessel wall information of a blood clot.
They are the most common type of stroke. The lumen of the blood vessel becomes narrowed and if it becomes occluded infarction occurs. About 30 to 40 percent of these types of stroke have a warning sign and these are called a TIA.
What is a TIA? A TIA stands for transient. ischemic attack.
I think of this as chest pain of the brain. This is a transient episode of neurologic dysfunction caused by a focal brain's spinal cord or retinal ischemia, but without acute infarction of the brain. So this should sound very similar to you as chest pain. So chest pain was our warning sign of a myocardial infarction or heart attack.
A TIA, or chest pain of the brain, is our warning sign of an infarction of the brain, which is called a stroke. The time frame for a TIA is that the neurological dysfunction has to resolve within 24 hours. A third of patients will not experience another event, a third will have more TIAs, and a third will have a stroke.
80% of these TIA symptoms that last longer than an hour are permanent. What are the risk factors for a TIA and then stroke? Well, there are all the same ones that you learned about for cardiovascular disease. Because look at that vessel in the picture. This is peripheral vascular disease.
These are the carotid arteries, same arterial walls that line the cardiac arteries, the coronary arteries. So if the lifestyle and the genetic factors that affect the coronary arteries, same ones that are going to affect the carotid arteries. So of course, there's non-modifiable things like age, sex, race, ethnicity, but there are modifiable risk factors, as you guys know, like hypertension and diabetes and obesity and smoking.
So all of those same risk factors that were discussed with our cardiovascular disease apply here. Remember, this is a warning sign of a stroke, and so that's very important for patients to know. Because what do most patients do? They have these symptoms, they wait for them to go away, and then they go away, and they're excited they went away. But good education needs to be given that this is a warning sign of impending infarction.
Another type of ischemic stroke is an embolic or what's also known as a cardiogenic stroke. These strokes occur when an embolus lodges in and includes a cerebral artery resulting in infarction and edema of the area supplied by the involved vessel. Cardiogenic embolic strokes are associated with cardiac dysrhythmias, usually atrial fibrillation. Embolic strokes can also be associated with valvular heart disease and thrombi in the left ventricle. Emboli originate from the heart and circulate to the cerebral vasculature, most commonly the left middle cerebral artery, resulting in a stroke.
Embolic strokes may be prevented by the use of anticoagulation therapy in patients with atrial fibrillation. Remember 15% of total strokes are hemorrhagic. Hemorrhagic strokes result from bleeding into the brain tissue itself or into the subarachnoid space or ventricles.
Intracerebral hemorrhage is bleeding within the brain caused by a rupture of a vessel. Most often there is a sudden onset of symptoms with progression over minutes to hours because of the ongoing bleeding. The prognosis of intracerebral hemorrhage is poor.
Subarachnoid hemorrhage occurs when there is intracranial bleeding into the cerebral spinal fluid-filled space between the arachnoid and pia mater, on the surface of the brain. 80% of hemorrhagic strokes are caused by uncontrolled hypertension. Most of these are viewed as the silent killer because they do not have a warning sign of the aneurysm until the rupture has occurred.
One distinguished clinical manifestation of a hemorrhagic stroke is the patient may report the worst headache of their life. This is because of the rapid increase of intracranial pressure. And because of the increase in intracranial pressure, they may also have decreased level of consciousness, nausea and vomiting, and seizures. But what are some other clinical manifestations of a stroke?
Stroke clinical manifestations may not significantly differ between ischemic and hemorrhagic stroke. The reason for this is that destruction of neural tissue is the basis for neurologic dysfunction caused by both types. The clinical manifestations are related to the location of the stroke. So knowing what the different parts of the brain do is important to understanding how your patient will present. A stroke can have an effect on many body parts, including motor activity, bladder and bowel elimination, intellectual function, spatial perceptual alterations, personality, affect, sensation, swallowing.
and communication, just to name a few. Motor deficits include impairment of mobility, respiratory function, swallowing, and speech, gag reflex, and self-care abilities. There are some general stroke clinical manifestations seen in patients based on which side of the brain was damaged.
These are very important as a nurse to understand so you can plan the care of your patient. If your patient had a left-sided stroke, which means the brain is damaged on the left side, I just want to make that clear because I've had many nurses tell me that a patient has had a left-sided stroke because the left side of the body is affected or a right-sided stroke. because the right side of the body is affected.
But when we say the patient has had a left-sided stroke, it means the brain damage is on the left side. So a patient with a left-sided stroke, in general, what you will see as clinical manifestations, they will have right-sided hemiplegia or hemiparesis. And that's because the opposite side of the body's motor activity is affected. They will have impaired right and left discrimination.
So they have difficulty differentiating right from left. They have impaired speech aphasias. So their communication is affected.
Why is that true? Because our communication centers are predominantly on the left side of the brain. The left hemisphere is dominant.
for language skills in most persons. Wernicke's area, which is your receptive area, is responsible for all the information coming in, the sound, and integrating that. So when it's damaged, the patient will have receptive aphasia, when neither sounds of speech nor its meaning can be understood.
Also, Broca's area is in the left hemisphere for most patients, and when that is damaged, the patient will have expressive aphasia, which is difficulty speaking and writing. Left brain stroke is also more likely to result in memory problems related to language, reading, and writing. Now for a patient with a right-sided stroke, which means the brain damage is on the right side, their general stroke clinical manifestations involve left-sided hemiplegia hemiparesis. Remember, because the opposite side of body motor activity is affected. And they experience something that is a fascinating phenomena called left-side neglect.
Remember, the right side of their brain is damaged, so the left side of their body, which will have potentially hemiplegia, hemiparesis, they do not believe it exists. And this is fascinating when you have a patient that is exhibiting this, because they do not believe that left side is there at all. And what does this do?
It increases their potential for injury. Have you seen your stroke survivor leave food on half of their plate or forget to put their recovering arm into a shirt or sleeve or not turn their head in your direction when you speak? That could be part of left-sided neglect.
It is fascinating. They will only brush hair on half their head, put makeup on half of their face, brush half their teeth. It is really a fascinating phenomenon.
to witness. They also may experience perceptual sensory deficits, which is the ability to interpret sensation. They are unable to perceive relationships of two or more objects, to know the position of their body and motion, inability to interpret visual, tactile, or auditory stimuli.
A stroke on the right side of the brain is more likely to cause problems in spatial perceptual orientation. So these patients are at huge risk for injury because of all of these different clinical manifestations. Patients with right-sided stroke also tend to be more impulsive, have impaired judgment, move more quickly, and have impaired time concepts.
So a lot of safety issues with these patients. Here is just another picture showing those general stroke clinical manifestations by the side of the brain that is damaged. So that is the end of our discussion on types of stroke and clinical manifestations seen in stroke. I look forward to sharing with you the management of stroke patients. Take care.