Cerebral infarction can cause death and permanent disability. This article explains what a stroke is and its consequences.
Stroke is the fourth cause of death worldwide, the first cause of disability and the third cause of dementia. Despite efforts in prevention, the incidence of cerebrovascular disease rises every year in underdeveloped countries. Strokes are more frequent in those over the age of 55. However, strokes in younger persons are not unheard of.
There are many types of stroke, including ischemic stroke, cerebral hemorrhage, lacunar infarct, and many others. The different terms and definitions involved in the subject can be overwhelming. I am a medical doctor, and in this article, I will explain each of these terms clearly and simply. Keep reading to learn everything you need to know about strokes directly from the hands of an M.D.
What is a cerebral infarction?
The first step in understanding stroke is learning what an infarct is. The medical definition of an infarct is tissue necrosis due to prolonged ischemia. There are two words in that definition that you probably don’t understand. Still, their meaning is straightforward: necrosis means cell death and ischemia means inadequate blood flow. So, simply put, an infarction is the death of a tissue due to prolonged insufficient blood flow. This definition applies to all types of infarction, from myocardial infarction all the way to gut infarction.
A cerebral infarction is focal brain necrosis due to prolonged ischemia. Brain necrosis causes a loss of brain function that results in symptoms.
Is an infarction a stroke?
Yes, but not just any stroke.
There are two kinds of stroke: ischemic stroke and hemorrhagic stroke. A cerebral infarct is an ischemic stroke, a sudden loss of circulation to an area of the brain that results in an acute loss of cerebral function. A hemorrhagic stroke is a brain hemorrhage resulting from a weakened blood vessel that breaks and bleeds into the surrounding brain tissue. Blood compresses the tissue causing a loss of brain function.
Both types of stroke cause very similar symptoms. It is impossible to distinguish between the two without the help of a CT scan or an MRI (specialized imaging medical exams).
What is a hemorrhagic stroke?
A cerebral hemorrhage is an intracranial bleed caused by the leakage of small intracerebral arteries into the brain. Hemorrhagic strokes are far less frequent than ischemic strokes. According to research, hemorrhagic strokes only represent 13% of all strokes. However, they are more severe and have a higher mortality rate than ischemic strokes. Patients with ischemic and hemorrhagic strokes have similar symptoms, those with brain hemorrhage tend to be more clinically ill.
A hemorrhagic stroke can be an intracerebral hemorrhage or a subarachnoid hemorrhage. In an intracerebral hemorrhage, bleeding occurs directly inside the brain. In a subarachnoid hemorrhage, bleeding occurs on the surface of the brain.
What are the causes of a hemorrhagic stroke?
Ischemic and hemorrhagic strokes share many of the same risk factors. However, certain conditions tend to cause more bleeding than ischemia.
Common causes of hemorrhagic stroke include the following:
- Bleeding disorders: Persons with coagulation disorders such as hemophilia, liver cirrhosis, and von Willebrand disease have increased risk of bleeding into the brain.
- Anticoagulant medication: People who take anticoagulant drugs such as warfarin and heparin are more like to have an intracranial bleed than the common population.
- Hypertension: The majority of hypertension-induced strokes are ischemic, but most hemorrhagic strokes are due to hypertension. In fact, over two-thirds of hemorrhagic stroke patients suffer from preexisting or newly diagnosed hypertension. Chronic hypertension damages the small arteries of the brain. A diseased cerebral artery is more likely to break and cause an intracerebral hemorrhage.
- Arteriovenous malformations: In normal conditions, an artery carries blood from the heart to the tissue. A vein carries blood from the tissue from the heart. An arteriovenous malformation is an abnormal connection between an artery and a vein that bypasses the tissue. The blood vessels in an arteriovenous malformation are weaker than regular vessels. Over the years, these weak vessels dilate and eventually break. Arteriovenous malformations occur in less than 1 percent of the global population.
- Aneurysms: An aneurysm is an abnormal dilatation in the wall of an artery, which is likely to break and produce a hemorrhage. Broken aneurysms are the most common cause of subarachnoid hemorrhage.
What is an ischemic stroke?
An ischemic stroke is the sudden loss of circulation to an area of the brain that results in brain cell death and loss of neurological function. According to the centers for disease control and prevention, ischemic strokes account for 87% of all strokes.
An acute ischemic stroke results from the occlusion of one of the arteries that feed the brain. There are two types of ischemic stroke: thrombotic and ischemic
In a thrombotic stroke, the blood clot that obstructs the cerebral artery comes directly from that artery. In contrast, in an embolic stroke, the blood clot comes from somewhere else in the body (i.e., the heart).
The mechanisms involved in cerebral thrombotic infarction are very similar to those involved in acute myocardial infarction. Most acute cerebral infarction cases originate on ruptured atherosclerotic plaques that promote the production of an obstructive blood clot. However, in young patients who are unlikely to suffer from widespread atherosclerosis, other causes need to be considered. Causes such as:
- Substance abuse (particularly cocaine)
- Sickle cell disease
- Hypercoagulable states
- Arterial dissection
- Venous thrombosis
What happens in an embolic stroke?
In an embolic stroke, a blood clot travels from a distant part of the body. The most common sites are the heart and the arteries in the chest’s upper arteries (i.e., the carotid artery).
A Cardioembolic stroke is a consequence of a diseased heart, particularly in conditions where there is turbulent blood flow inside the heart, like in valvular heart disease, and situations where blood remains still for too long, like atrial fibrillation. Blood clots then travel from the heart to the brain. The arteries in the brain are smaller than those in the heart, so when the clot reaches a small enough artery, it gets stuck, causing cerebral embolism and acute infarction.
Where is the most common site of cerebral infarction?
The location of a cerebral infarction depends on the occluded artery. The brain has two hemispheres, right and left, each hemisphere is fed by three major arteries and their branches. The arteries are the anterior cerebral artery, the middle cerebral artery, and the posterior cerebral artery. The anterior and posterior arteries come from the internal carotid artery and form the anterior system. The posterior cerebral artery arises from the basilar artery and creates the posterior system.
The anterior cerebral artery irrigates the inner portion of the frontal lobe and parietal lobes and the basal ganglia. The middle cerebral artery supplies the outer parts of the parietal and frontal lobes and the temporal lobe, the basal ganglia, and the internal capsule. The posterior cerebral artery supplies the occipital lobe, the brainstem, and the thalamus. The middle cerebral artery provides most of the blood supply to the hemispheres.
The occlusion of the middle cerebral artery or its branches is the most common type of cerebral infarction. Middle cerebral artery infarction is responsible for over two-thirds of all cases of acute cerebral infarction. Most infarcts in the middle cerebral artery territory affect the somatosensory cortex than contains motor and sensory functions of the face and the upper extremity.
The classical clinical presentation consists of hemiparesis, facial paralysis, and sensory loss of the face and upper extremity. If the infarct happens in the dominant hemisphere symptoms might also include:
- Difficulty speaking.
- Inability to produce or remember words.
- Neglect of an entire side of the body because the patient cannot see that area.
What is the difference between ischemia and infarction?
The fundamental difference between ischemia and infarction is that ischemia is the cause, and infarction is the consequence. Ischemia is deficient in blood flow to the tissue, while infarction is the death of that tissue because of the poor blood flow.
If ischemia is reversed promptly, it won’t cause any permanent structural damage. Infarctions, on the other hand, are irreversible. Once the damage is there, it will stay there.
Ischemia does not cause permanent damage. It does, however, cause transitory symptoms. Transitory cerebral ischemia produces a mini-stroke or, as doctors like to call it, a transient ischemic attack. A transient ischemic attack (TIA) is an acute episode of neurological dysfunction consequence of focal cerebral ischemia without acute brain infarction. A TIA usually lasts for a few minutes and no more than 24 hours after symptom onset. In most cases, symptoms disappear before the patient reaches the emergency department. The symptoms can resemble those seen in an acute stroke. Usual symptoms include some of the following:
- Weakness or numbness in one side of the body (hemiparesis)
- Paralysis of one side of the face (facial paralysis)
- Blindness in one eye
- Difficulty speaking
- Incoherent words
- Balance issues
- Abnormal sense of smell or taste
- Passing out (in rare cases)
Despite the disappearance of symptoms, the physician should perform a CT scan to rule out cerebral infarction and brain hemorrhage. A TIA isn’t just a funny anecdote. It is also a warning sign. The risk of ischemic stroke is 4% after 48 hours of a TIA, 8% at 30 days, and 9% at 90 days. The probability of having a cerebral infarction in the five years following a TIA is 25%. Patients with a TIA are also at increased risk of suffering from coronary artery disease.
What are the symptoms of cerebral infarction?
Each part of the brain has a different function. It’s fed by a different artery, so the symptoms of a cerebral infarction vary according to the affected area of the brain. The classic presentation of a stroke of a sudden loss of strength or paralysis on one side of the body doesn’t happen in all patients. Some may present with other neurological deficits depending on the location of the stroke. The one thing all these symptoms have in common, whatever the location, is their acute nature. Cerebral infarction occurs suddenly. One minute the person is perfectly fine, and one minute later he can’t move.
Common stroke symptoms include:
- Paralysis in one side of the body (rarely on both sides)
- Numbness in one side of the body
- Sudden slurring speech
- Sudden dizziness or loss of balance
- Blackened, blurry or double vision
- Facial paralysis.
- Sudden loss of consciousness
- Sudden severe headache
Although these symptoms may occur alone, they are more likely to appear in combination. Hemorrhagic strokes present in the same way as ischemic strokes. However, symptoms such as headaches decreased level of consciousness, nausea, and vomiting are more frequent in hemorrhagic strokes.
Conditions such as low blood sugar, low sodium levels, seizures, brain cancer, and complicated migraines might present with stroke-like symptoms.
If you have any of these symptoms, rush to your nearest medical facility or call 911—the earlier the treatment, the better the outcome and prognosis.
Is there such as thing as an asymptomatic stroke?
You can have a stroke and not notice it, it is a silent cerebral infarction. Conditions like carotid stenosis, hypertension, and atrial fibrillation are the most significant risk factors for having a silent stroke. Like symptomatic strokes, silent strokes occur because of a blood flow obstruction. The difference is that in asymptomatic strokes, the infarct occurs in an area that doesn’t control visible functions like talking or walking. The fact that you don’t notice the damage doesn’t mean that damage isn’t there. Silent strokes damage small parts of the brain. Still, if you have several asymptomatic strokes, damage cumulates, and eventually, you will start noticing some deficits. Symptoms of a silent cerebral infarction include:
- Difficulty concentrating
- Disorientation in familiar places
- Loss of bladder control
- Loss of memory
- Emotional issues
Having multiple silent strokes also increases the risk of suffering from an Alzheimer-like disease called vascular dementia or multi-infarct dementia.
The diagnosis of a silent stroke is commonly made after a routine CT or MRI. The damage produced by silent strokes isn’t reversible. However, patients may benefit from cognitive therapy and regain some degree of function.
Which side is worse for a stroke?
In most people, the left side of the brain controls the ability to use and understand language. So logically, a left cerebral infarction is more likely to produce slurred speech, use of incoherent words, inability to use and understand language, inability to write, and inability to read.
This is why most people think left-sided strokes are worse than right-sided strokes. However, the right side of the brain controls the ability to pay attention, recognize objects, and the capacity to be aware of our own body. So, in the end, a stroke in the right of the brain can be just as bad as on the left side.
What is carotid artery stenosis?
Carotid artery stenosis is a narrowing in the carotid artery due to atherosclerosis. The carotid artery is the most important source of blood to the brain, and complete blockage of the artery might lead to a stroke. Carotid artery stenosis can be diagnosed with a carotid ultrasound, CT angiogram, or magnetic resonance angiography.
Most of the time, carotid stenosis requires surgical care. Carotid endarterectomy is a procedure that removes the atheromatous plaque from the artery and restores blood flow. However, the plaque might grow again if you fail to control your risk factors.
The surgeon will make a small cut in your neck, exposing the blocked section of the artery, the surgeon will remove open the artery and remove the plaque. He will then repair the artery with stitches or a patch made with vein or artificial material.
How are brain lesions diagnosed?
Strokes are diagnosed through neuroimaging studies. Brain imaging is essential to discard mimics such as complicated migraine and to distinguish cerebral infarction from a cerebral hemorrhage. A non-contrast CT scan is the first step for diagnosis. This is a quick study that helps doctors differentiate between an ischemic stroke and a hemorrhagic stroke. This distinction is vital for the initiation of treatment. In the first hours after the onset of symptoms, signs of ischemia might be absent or be challenging to see. Still, the absence of a brain hemorrhage is enough to initiate treatment at this stage.
Magnetic resonance imaging (MRI) can detect ischemic changes earlier than CT scanning. Nowadays, many health centers include it in their basic stroke imaging protocol. However, MRI is an expensive test that requires patients to remain still in an uncomfortable position for minutes. And is contraindicated in those with pacemakers.
Your attending physician may also do an electrocardiogram to evaluate your heart and discard a cardioembolic stroke due to atrial fibrillation. An angiogram is another routine stroke test used to detect atherosclerosis and blockages in your cerebral arteries.
What is the treatment for brain infarction?
In cerebral infarction, the main objective is to save as much healthy brain tissue as possible. There is an area with decreased blood flow surrounding the dead tissue. That area can be saved with blood flow restoration. But to achieve it, doctors have to act soon.
Thrombolytic therapy is the mainstay of treatment for ischemic stroke patients. It consists of injecting a drug that breaks the obstructing clot restoring blood flow to the brain. The drug Alteplase is the gold standard of thrombolytic therapy. Still, it must be delivered within the first 3.5 hours after symptom onset for it to work. People who receive alteplase early after having a stroke are less likely to die and more likely to recover without permanent disability.
Alteplase can be deadly if administered in a hemorrhagic stroke, so previous imaging studies are a must. Other contraindications include:
- Age older than 80
- Use of anticoagulant medication such as heparin or warfarin
- History of stroke and diabetes
- History of prior intracranial bleeding
- Surgery in the last 14 days
- Systolic blood pressure over 185
- Low platelet count
Guidelines from the American Heart Association recommend using an antiplatelet such as aspirin within the first 24 to 48 hours.
Mechanical thrombectomy is an alternative to thrombolytic therapy for patients in which the procedure is ineffective or contraindicated. The procedure consists of inserting a catheter into a large blood vessel of the brain to pull out the obstructing clot. This surgery should be performed 6 to 24 hours after the onset of symptoms.
What happens if when alteplase is administered too late?
In the best-case scenario, alteplase won’t do anything if administered after four hours. In the worst-case scenario, thrombolytic therapy will produce a hemorrhage. Hemorrhagic transformation is a common complication of cerebral infarction, and the risk increases with alteplase administration. Severity ranges from a few blood spots to massive cerebral hemorrhage. After necrosis settles in, brain arteries lose their capacity to keep fluid from trespassing the brain. With blood flow restoration, blood leaks into the brain. Small hemorrhages do not alter the clinical outcome. Still, extensive hemorrhages can cause significant deterioration and an increase in the mortality rate.
What is the treatment for a hemorrhagic stroke?
Treating a hemorrhagic stroke is a bit more complicated than treating an ischemic stroke.
Hemorrhagic stroke treatment has four primary goals:
- Basic life support
- Seizure control
- Blood Pressure control
- Intracranial pressure control
The first step is stabilizing vital signs and intubation of patients with a decreased level of consciousness. Seizures are present in 28% of patients and require treatment with drugs like lorazepam, diazepam, and phenytoin. Significantly elevated blood pressure increases the risk of rebleeding and hematoma expansion. Ideally, systolic blood pressure should be under 140 mmHg, but aggressively reducing BP can lead to hypoperfusion and cerebral ischemia. The goal is to reduce 25% of the mean BP to avoid complications.
Bleeding inside the skull causes the pressure inside it to rise. Intracranial hypertension can cause permanent disability, blindness, and even death. Patients with elevated cranial pressure may require treatment with an osmotic diuretic, such as mannitol, to prevent complications.
Surgery may be required in some cases, particularly those with significant bleeding and those caused by arteriovenous malformations or aneurysms. In the case of an aneurism, the surgeon might choose to clip the aneurysm, installing a clamp to prevent it from bleeding further.
Despite advances in treatment, the mortality rate of hemorrhagic strokes remains high. Some studies suggest that about 50% of patients with a hemorrhagic stroke die even when they receive adequate treatment.
What is a massive cerebral infarction?
A massive cerebral infarction is a catastrophic form of cerebral infarction that involves the entire middle cerebral artery territory. In most cases, a massive cerebral infarction causes coma and brain death within two days. Sufferers are severely disabled and have a poor quality of life. Massive cerebral infarctions represent 2% to 10 % off all ischemic strokes. Surgical management of these patients slightly increases the possibility of survival, but the prognosis is still bleak at best.
How can I prevent a cerebral Infarction?
- Stop smoking: Smoking increases the risk of coronary artery disease and cerebrovascular disease.
- Eat healthily: A diet rich in fat and complex carbohydrates is one of the most significant risk factors for cardiovascular disease. Also, try lowering your salt intake, too much salt a day increases your blood pressure.
- Keep your blood pressure in check: If you suffer from hypertension, be consistent with your medication. Uncontrolled blood pressure leads to complications such as kidney disease, heart attack, and stroke.
- Keep your diabetes in check: Along with high blood pressure, diabetes is one of the most critical risk factors for heart and cerebrovascular disease.
- Manage your weight: Obesity and overweight are associated with a higher risk of metabolic and cardiovascular diseases.
- Exercise: Research shows that 30 minutes a day of moderate aerobic exercise can reduce your risk of having a stroke by 40%.
- Cut down on alcohol: Alcohol increases your blood pressure and can cause atrial fibrillation. Alcoholic beverages are high in calories and cause weight gain. Frequent alcohol consumption makes a stroke three times more likely.
- Have a yearly medical check-up: An annual visit to the doctor will help detect underlying conditions such as internal carotid artery stenosis, hypertension, and diabetes early. Early detection and treatment prevent complications such as stroke.
Can you ever fully recover from a stroke?
Every patient reacts differently to a stroke. No doctor or physical therapist can promise a patient complete recovery after a stroke. Recovering from a stroke is a long process that requires a lot of hard work, commitment, and patience. According to the National Stroke Association, 10% of patients recover completely, 25% recover almost completely with minor deficits, 40% improve moderately and may require some degree of special care, 10% need long term care in a specialized facility.
Some factors that determine the degree of recovery include:
- The severity of the stroke: How much brain tissue was compromised.
- Age: Younger patients tend to recover better
- Other medical conditions: like hypertension, diabetes mellitus, and heart disease
- How soon you begin recovery
- The quality of the rehabilitation therapy
- Your motivation
Recovery requires rehabilitation therapy. The sooner you start, the better. Research shows that the fastest gains occur in the first 3 months after the stroke. The early beginning of this process increases the possibility of regaining neurological function.
Different stroke survivors benefit from different rehabilitation methods. Experts recommend that patients experiment with varying rehabilitation techniques to find the one that works best for them.
What is the life expectancy after a stroke?
Despite modern advances in treatment, life expectancy statistics remain somewhat grim. Having a stroke can significantly decrease a person’s life expectancy. A Swedish research project followed 2.051 first-ever stroke patients for 30 years. In the 65-72 year age group, 11% survived 15 years after the stroke, while in the under 65 years group, 28% survived after 15 years. The mortality in both age groups was higher than in the general population.
Several factors affect life-expectancy after a stroke:
- Recovery of function: Recovery of neurological function is a key prognosis factor for survival, particularly at older ages. The severity of disability following a stroke is one of the most critical elements of long-term survival.
- Age: The ages over 70 is associated with a lower life expectancy.
- The number of strokes: Those who have multiple strokes suffer from higher mortality rates.
Can a stroke be ischemic and hemorrhagic at the same time?
In some cases, an ischemic stroke transforms into a hemorrhagic stroke. Hemorrhagic transformation occurs in the case.
What can you do if you have risk factors or symptoms of it?
This tool is a stroke symptoms checker. It gathers the most important risk factors, signs, and symptoms to determine the likelihood of somebody developing this condition. Also, if someone has already had some sort of presentation, it will detect them too. It is free, and it would only take a few minutes.