What is Middle Cerebral Artery Stroke (Stroke)?
The middle cerebral artery (MCA) is the artery that’s most commonly linked to acute strokes. This artery springs from the internal carotid artery and has four main branches – M1, M2, M3, and M4. These arteries provide blood to certain parts of the brain, specifically the frontal, temporal, and parietal areas, as well as deeper parts like the caudate, internal capsule, and thalamus. Since the MCA has such a wide reach, strokes affecting this area can result in many different symptoms. These symptoms depend on which branches and parts of the brain are impacted.
What Causes Middle Cerebral Artery Stroke (Stroke)?
There are various factors that increase the risk of strokes. These factors can either be changed (modifiable) or cannot be changed (nonmodifiable). It’s worth noting that many risk factors for hemorrhagic (bleeding in the brain) and ischemic (blocked blood supply to the brain) strokes are the same.
Sadly, some stroke risk factors are nonmodifiable, they include age, sex, race, and genes. Simply put, as you grow older, your stroke risk increases; men are at a higher risk at a younger age, but women are more likely to die from a stroke; African Americans are at a higher risk, followed by Hispanics and Native Americans compared to whites.
On the other hand, you can do something about modifiable risk factors such as high blood pressure, smoking, obesity, excessive alcohol intake, and diet, which contribute to both ischemic and hemorrhagic stroke. But high cholesterol, physical inactivity, diabetes and heart-related conditions like heart muscle disease, heart failure, and irregular heart rhythm are risk factors specific to ischemic stroke, not hemorrhagic stroke.
Hemorrhagic stroke is usually due to high blood pressure, especially in lesser developed countries where high blood pressure is a hidden problem because of infrequent health check-ups and diagnosis. Occasionally, hemorrhagic strokes can result from angiopathies, a disease of the blood vessels which can be detected with a brain angiogram.
Ischemic stroke can be grouped into several categories such as atherosclerotic, cardioembolic, lacunar, and cryptogenic. However, also it can be due to specific causes like inflammation of blood vessels, tearing of the inner layer of arteries, or genetic disorders. In the case of atherosclerosis, severe narrowing or blood clot formation can occur due to fat deposits that can block blood vessels leading to brain ischemia. While, cardioembolic strokes can happen in the presence of irregular heart rhythm or a hole in the heart in younger individuals, especially if they also have a clot in the deep veins. These clots can move from the heart, through the left ventricle, into the major artery that supplies the body, and get lodged in the main arteries that supply the brain. The smaller and deeper brain arteries that cause lacunar strokes are more often affected by high blood pressure and diabetes than by blood clots.
Risk Factors and Frequency for Middle Cerebral Artery Stroke (Stroke)
Stroke is one of the top causes of death both in the United States and globally. It is notably more common in adults over the age of 20 and is particularly prevalent as an ischemic stroke, which frequently occurs in a specific brain region called the MCA territory.
Generally, young and middle-aged men are at a higher risk of stroke, but women are more likely to experience stroke over their lifetime. The risk varies between races as well, where it is more common in Black and Hispanic individuals compared to White individuals.
The frequency of strokes and deaths from strokes have decreased in wealthy countries over recent years, possibly due to better steps taken to prevent strokes. However, this is not the case for middle and low-income countries; their stroke rates have remained the same, and the number of stroke-related deaths has even increased.
- Stroke is the fifth leading cause of death in the U.S. and the second worldwide.
- About 2.6% of U.S. adults over 20 years old have had a stroke.
- Around 85% of these strokes are ischemic strokes, with over half happening in the MCA territory of the brain.
- Young and middle-aged men have a higher stroke risk than women, but women have a higher lifetime risk – 20% to 21% for women compared to 14% to 17% for men.
- Stroke risk is higher in Black and Hispanic individuals than in White individuals.
- Stroke rates and deaths from stroke have dropped in high-income countries, probably thanks to improved prevention measures.
- In contrast, stroke rates haven’t changed in middle and low-income countries, and stroke-related deaths have increased.
Signs and Symptoms of Middle Cerebral Artery Stroke (Stroke)
When people come to the hospital with less than 24 hours of symptoms such as weakness, dizziness, numbness, speech problems, or changes in vision, they are usually treated for a potential stroke. This immediate action is critical because there are specific steps to follow to quickly gather important health history, conduct a targeted physical exam, get emergency lab tests, and schedule necessary imaging.
One of the most critical pieces of information is the ‘last known normal,’ which is the last time the patient felt or seemed to be at their normal health. Knowing this helps doctors determine what treatments are available. If the ‘last known normal’ was within 4.5 hours of arriving at the hospital, the patient could be eligible for a clot-busting medication called tissue plasminogen activator (TPA). If it was within 24 hours, they might qualify for brain surgery.
Other key details include when the symptoms started, what symptoms they had, and whether these symptoms have changed, got better or worse. Also, whether the patient has any conditions that might prevent them from safely taking TPA. Things to consider include:
- History of bleeding in the brain
- A stroke in the past three months
- Recent surgery, especially on the spine or brain
- Recent internal bleeding
- Use of blood-thinning medications
- Having had certain types of procedures involving needles or IV lines
- Recent trauma or heart attack
The patient’s broader medical history is also important, as conditions like diabetes, high blood pressure, and high cholesterol can increase the risk of stroke.
The most important physical exam for a suspected stroke is the National Institute of Health Stroke Scale, a standard method of assessing stroke patients. This scale is especially helpful for identifying and locating strokes in the front part of the brain, such as in the middle cerebral artery. The scale assesses:
- Feeling, strength, and coordination in all four limbs
- Ability to speak and understand speech
- Field of vision
- Knowledge of oneself and time
- Symmetry and sensation in the face
Major strokes in the middle cerebral artery are usually easy to recognize because they often present with clear signs of a stroke, such as weakness on one side of the body, problems with gaze, visual field deficits, and speech issues, particularly in the dominant hemisphere. Chronic abnormalities, like lasting effects from previous strokes, should also be noted during this exam. Finally, the patient’s blood pressure must be taken, as both high and low blood pressure can cause neurological symptoms, and it must be under control (less than 180/110) before IV TPA can be given.
Testing for Middle Cerebral Artery Stroke (Stroke)
When dealing with a suspected acute stroke, two types of imaging methods, namely CT (computed tomography) scans and MRI (magnetic resonance imaging), can be used. Both should be completed without contrast, and vascular imaging should also take place. The CT scan can help identify things like past strokes, different kinds of bleeding, and signs that point towards a severe acute stroke. Meanwhile, the MRI, particularly the DWI type, can indicate similar things and can also detect an acute stroke swiftly, within minutes to hours.
The next stage involves a CT or MR angiogram, which captures images from the main artery (aorta) to the brain. It helps in identifying areas of narrowing or blockages that might be causing the stroke symptoms. An additional scan (perfusion scan) is carried out to measure how much tissue is already damaged versus the tissue at risk, which can play a significant role in determining if the patient is a good candidate for a procedure called mechanical thrombectomy.
There are also essential lab tests to be done. Some of these include a coagulation panel to evaluate blood clotting factors, complete blood count, and basic metabolic panels. Quick blood glucose testing helps rule out hypoglycemia, a condition that can mimic stroke symptoms. Testing for glycosylated hemoglobin levels and a lipid panel is crucial as well, as part of secondary stroke prevention involves managing these levels. Finally, cardiac enzymes should be checked to cross out any potential cardiac abnormalities.
Once stroke is confirmed, it is essential to monitor the patient’s heart health. An EKG test, transthoracic echocardiogram, and telemetry monitoring can identify any potential thrombus or cardiac abnormalities that could have caused the stroke. Some of these abnormalities that can increase stroke risk include atrial fibrillation, patent foramen ovale, or lack of movement of the cardiac walls. If no abnormalities are found, yet stroke possibility is high, the patient might need a transesophageal echocardiogram or cardiac MRI for a better evaluation. Lastly, a Holter monitor will be used to observe cardiac activities, usually for 30 days following discharge, to check if any noticeable irregular heartbeats are recorded.
Treatment Options for Middle Cerebral Artery Stroke (Stroke)
For people who suffer from an MCA stroke (a type of stroke that occurs in the middle cerebral artery), immediate treatments can include IV tissue plasminogen activator (TPA), which is a type of drug that dissolves blood clots, and a procedure known as a thrombectomy to remove the clot. These treatments are time-sensitive; the TPA must be administered within 4.5 hours of the stroke, and the thrombectomy must take place within 24 hours. If the window of opportunity for these interventions has passed, then treatment focuses on managing symptoms and preventing a second stroke.
Preventing a second stroke involves managing risk factors such as diabetes, high blood pressure, high cholesterol, and smoking. For diabetics, maintaining a blood sugar level measured by a test called glycosylated hemoglobin under 6.5% is vital. Regular checks of this value, a controlled diet, and diabetic medication can help achieve this.
In the first day after a stroke, it’s permissible for a patient’s blood pressure to be a bit high to help protect the brain from further damage due to poor blood flow. However, after the first 24 hours, a patient’s blood pressure should be kept below 140/90mmHg to reduce the chances of another stroke. This regulation requires adjusting medications and close monitoring of blood pressure levels.
Managing high cholesterol, or hyperlipidemia, can also help prevent a second stroke. This involves monitoring the patient’s low-density lipoprotein (LDL) levels, a type of cholesterol. It’s recommended that LDL levels stay below 70. If needed, medications like atorvastatin or rosuvastatin can be used to control cholesterol.
Smoking is also a significant risk factor that needs to be addressed. Smokers who have had a stroke should be strongly encouraged to quit.
A crucial part of stroke prevention involves the use of medications to prevent blood clots (antiplatelet or anticoagulant). The appropriate medication depends on the patient’s specific circumstances, such as the severity of the stroke and the cause. One common treatment includes aspirin and clopidogrel for 3 months, followed by a lower dose or a single medication afterwards. Those with certain conditions like a blood clot in the heart or abnormal heart rhythms may need to continue on anticoagulants instead.
It’s important to note that a stroke patient’s treatment plan needs to be closely monitored and possibly adjusted in the weeks and months following their stroke to mitigate the risk of subsequent strokes.
What else can Middle Cerebral Artery Stroke (Stroke) be?
When a patient presents with symptoms typical of a stroke, there are many other conditions that could cause similar symptoms and need to be ruled out. A stroke requires immediate medical attention, so it’s important to identify whether it’s a stroke or another condition quickly. Common signs of stroke include weakness or numbness on one side of the body, a drooping face, and difficulties with speech.
Various serious issues in the brain could cause symptoms similar to a stroke. These include bleeding in the brain (subdural hematomas), brain haemorrhages, or brain masses. These conditions can affect the same areas of the brain as strokes and may require urgent surgery. They can quickly be spotted through immediate medical imaging tests like a CT scan or MRI when probing for a stroke.
Seizures, particularly continuous seizures (status epilepticus), may look like a stroke as they can cause a loss of movement and conscious awareness. This is urgent and requires immediate treatment with anti-seizure medications.
Conditions where the body’s immune system mistakenly attacks the body’s cells, like multiple sclerosis, could confuse with the presentation of a stroke. Symptoms such as vision loss, numbness, or weakness that are more prevalent in a particular body part may be suggestive. Help differentiating will come from a detailed patient history and MRI scans. Unlike strokes, the symptoms of these conditions don’t usually occur suddenly and often come and go over time.
Various toxic, infectious, and metabolic disorders also need to be considered during diagnosis. Conditions like sepsis, imbalance of body salts, extremely high or low blood sugar, can all cause symptoms similar to a stroke. Unusual appearances caused by these conditions could resemble a stroke and present with difficulties speaking and apparent strength loss. This is why it’s important to distinguish whether symptoms affect one particular body side during the evaluation. When such symptoms are noticed, extra laboratory tests, including infection-related tests, are often required on top of those typically run in acute emergency situations.
Some migraines are so severe that they can imitate strokes by causing one-sided weakness or numbness. A regular headache would usually accompany these symptoms, and the patient typically has a previous history of migraines. Diagnosis requires a thorough collection of patient history and usually, treating the migraine results in symptom resolution.
Lastly, some psychological disorders, such as panic attacks or conversion disorders, can mimic stroke symptoms like one-sided numbness or weakness. However, these are usually considered less likely possibilities and are used as a last resort diagnosis considering other conditions that closely mimic a stroke can be dangerously fatal if misdiagnosed. A detailed patient history is crucial in diagnosing these cases.
What to expect with Middle Cerebral Artery Stroke (Stroke)
The recovery after a stroke in the middle cerebral artery can depend on several things. The most important factors are the size of the stroke, whether the patient was treated with clot-busting drugs or had a procedure to remove the clot, and their access to rehab therapy after the stroke. Predicting the recovery outcome after a stroke can be tough, especially right after it’s happened. It could take anywhere from weeks to a year for the patient to get back to a new normal level of activity.
Patients who had smaller strokes normally get better quickly within a couple of weeks followed by a slow and steady recovery over a few months. But for larger strokes, it’s difficult to predict the recovery even in the first three months due to individual differences. As for mental abilities, how a patient feels by day four often gives a good idea of what their mental state will be like in the future. That being said, it can take up to six months to adjust to daily living activities. It’s worth noting that physical therapy is equally beneficial for both older and younger patients when it comes to improving function.
Recovery estimation is more complex for severe strokes. These patients often struggle with brain swelling and altered consciousness. Survival is often based on whether crucial life-maintaining measures are followed. Many of these patients need procedures like a tracheostomy (inserting a tube into the windpipe to help with breathing) or percutaneous gastrostomy tube placement (inserting a feeding tube into the stomach). This can make hospital stays longer and raise the risk of infection. But, without these procedures, their lifespan can be significantly reduced because of their inability to protect their breathing passage or eat. For these patients, survival prospects are generally quite grim with a very low chance of recovery. Their survival time mainly depends on if they receive these life-sustaining procedures or not.
Possible Complications When Diagnosed with Middle Cerebral Artery Stroke (Stroke)
There are many complications that can occur after an MCA stroke. The majority of stroke patients experience some kind of issue during their recovery. Research shows that about 85% of patients experienced at least one complication just during their hospital stay and other experienced issues within 6 weeks of their stroke. This study followed patients for over two years.
The most common complications that occur in hospital include infections like pneumonia or urinary tract infections, falls, and pain. Some patients experience pressure sores, seizures, a second stroke, blockage of blood vessels (thromboembolism), and mood disorders such as depression. After being discharged from the hospital and over the next two years, the most common issues were still infections, falls, and pain, but the occurrence of mood disorders like depression and anxiety increased. The risk of seizures and suffering another stroke continued, and some patients had to be readmitted to the hospital.
The reasons why falls, pain, and infections are the major complications is due to the effects of MCA strokes. They often lead to decreased sensations and physical strength, making falls more likely. They can cause difficulty swallowing which can lead to choking or a decrease in movement can lead to the collapse of part of the lung (atelectasis) – both of these conditions can then enable the development of pneumonia. Limited movement also increases the chances of developing pressure sores and experiencing pain. This why a team of healthcare workers including doctors, nurses, and therapists is critical to improving the quality of life of stroke patients.
Those who have severe strokes often face more serious complications. Some of these could be life-threatening, such as the swelling of the brain (cerebral edema), altered level of consciousness, severe difficulty swallowing, and inability to protect their airway. Brain swelling typically worsens around 3 to 5 days after the stroke and can put pressure on the brain chambers (ventricles), leading to a change in the position of the brain structure, and in severe cases, brain herniation and death. Even if it doesn’t reach that extreme, it can severely affect a patient’s level of consciousness, making them unable to protect their airway or swallow safely. Doctors then face the difficult question of whether to insert air tubes into the windpipe (tracheostomy) or a feeding tube into the stomach (percutaneous gastric tube). Both of these procedures can also cause additional complications and infections. If doctors decide not to perform these procedures, it can also lead to death.
Preventing Middle Cerebral Artery Stroke (Stroke)
When it comes to dealing with stroke, the main focus for patients is learning how to reduce the chance of having another stroke and recognizing the warning signs of a stroke. In case of these signs, they should dial 911 and rush to the nearest stroke center.
Keeping another stroke at bay involves managing factors that can be changed, such as high blood pressure, elevated cholesterol levels, diabetes, diet, being overweight, and smoking. As part of the prevention strategy, quitting smoking is essential, and lifestyle and diet alterations are also advised. Patients are usually given aspirin if they weren’t taking it already. Their cholesterol and blood sugar levels are checked regularly. If a patient has high cholesterol levels or diabetes, the proper medication is prescribed. Patients are also guided to monitor their blood pressure regularly at home, and medication to control high blood pressure is fine-tuned as per individual needs.
For recognizing the signs of a potential stroke, the acronym BE FAST is used: balance, eyes, face, arms, speech, and time. ‘Balance’ signifies falling to one side or feeling dizzy; ‘eyes’ means a sudden loss of vision in one eye or seeing double unexpectedly; ‘face’ points to a droopy face; ‘arms’ refers to a weak arm or loss of feeling in the arm; ‘speech’ could mean slurring words, struggling to find words, or difficulty in speaking; and ‘time’ indicates that an immediate response is crucial- the sooner one reaches emergency care, the better the chances of recovery.