ADVANCEMENTS IN STROKE PREVENTION AND TREATMENT

Stroke is a medical condition that occurs when the blood supply to a part of the brain is interrupted or reduced, leading to the death of brain cells. This can happen due to a blood clot that blocks a blood vessel (ischemic stroke) or due to bleeding in the brain (hemorrhagic stroke).

There are also two less common subtypes of stroke:

Transient ischemic attack (TIA), also known as a “mini-stroke,” is a temporary blockage of blood flow to the brain that typically lasts less than 5 minutes. Symptoms may be similar to those of a stroke, but they usually disappear within a few minutes to hours.

Cryptogenic stroke is a type of stroke where the cause cannot be identified despite a thorough medical evaluation. It is estimated that 30% of all ischemic strokes are cryptogenic.

 

Stroke prevention and treatment have made significant advancements in recent years. Some of the major advancements in stroke prevention and treatment include:

• Prevention: One of the most significant advancements in stroke prevention is the development of anticoagulant medications such as warfarin and dabigatran that reduce the risk of blood clots, a major cause of strokes. In addition, lifestyle changes such as maintaining a healthy diet, exercising regularly, and quitting smoking have been shown to reduce the risk of stroke.
• Thrombectomy: Thrombectomy is a minimally invasive surgical procedure that can be used to remove blood clots from the brain. It is a highly effective treatment for ischemic strokes, which occur when a blood clot blocks blood flow to the brain.
• Telestroke: Telestroke is a telemedicine service that allows stroke specialists to remotely assess and treat stroke patients. Telestroke has been shown to significantly reduce the time it takes to diagnose and treat stroke patients, which can help prevent long-term disability and death.
• Mechanical Thrombectomy: Mechanical thrombectomy is a procedure where a catheter is inserted into the blocked artery in the brain and used to remove the clot. It is a highly effective treatment for acute ischemic strokes.
• Clot-busting medication: Clot-busting medications such as tissue plasminogen activator (tPA) can be used to dissolve blood clots that are causing an ischemic stroke. These medications are most effective when administered within a few hours of the onset of stroke symptoms.
• Neural stem cells: Neural stem cells are being studied as a potential treatment for stroke. These cells can differentiate into different types of brain cells and may be able to repair damaged brain tissue caused by a stroke.

Overall, these advancements in stroke prevention and treatment have greatly improved the prognosis for stroke patients and have reduced the number of deaths and disabilities caused by strokes. However, early recognition and treatment of stroke symptoms remain critical for a successful outcome.

 

Some of the risk factors for stroke include:

1. High blood pressure: Hypertension is the leading risk factor for stroke, as it damages the blood vessels in the brain and makes them more prone to rupture or blockage.
2. Smoking: Smoking increases the risk of stroke by damaging blood vessels and promoting the formation of blood clots.
3. High cholesterol: High levels of LDL (low-density lipoprotein) or “bad” cholesterol can lead to the formation of plaques in the blood vessels, which can increase the risk of blockages and stroke.
4. Diabetes: People with diabetes are at an increased risk of stroke due to damage to blood vessels caused by high blood sugar levels.
5. Obesity: Being overweight or obese can increase the risk of stroke, as it is often associated with other risk factors such as high blood pressure, high cholesterol, and diabetes.
6. Physical inactivity: Lack of exercise and physical activity can increase the risk of stroke by contributing to other risk factors such as obesity, high blood pressure, and high cholesterol.
7. Atrial fibrillation: This is an irregular heartbeat that can lead to the formation of blood clots in the heart, which can travel to the brain and cause a stroke.
8. Family history of stroke: People with a family history of stroke are at an increased risk of having a stroke themselves.
9. Age and gender: The risk of stroke increases with age, and men are more likely to have a stroke than women.
10. Previous stroke or TIA: People who have had a stroke or a transient ischemic attack (TIA) are at an increased risk of having another stroke.

 

Stroke clinical features by territory

The symptoms of stroke can vary depending on which part of the brain is affected. The main types of stroke include ischemic stroke, which is caused by a blockage in a blood vessel supplying the brain, and hemorrhagic stroke, which is caused by bleeding in the brain.

Here are the clinical features of stroke in different vascular territories:

1) Middle cerebral artery (MCA) territory:

The MCA is the most commonly affected artery in ischemic strokes. The clinical features of a stroke in this territory include:

• Contralateral hemiparesis (weakness or paralysis of one side of the body).
• Contralateral hemisensory loss (numbness or loss of sensation on one side of the body).
• Aphasia (difficulty speaking or understanding language) if the stroke occurs in the dominant hemisphere.
• Neglect or inattention to one side of the body if the stroke occurs in the non-dominant hemisphere.
• Homonymous hemianopsia (loss of vision in half of the visual field).

 

2) Anterior cerebral artery (ACA) territory:

The ACA supplies blood to the frontal lobes of the brain. The clinical features of a stroke in this territory include:

• Contralateral hemiparesis or hemisensory loss (usually affecting the leg more than the arm).
• Urinary incontinence or retention.
• Changes in personality, behavior or emotional control.
• Apraxia (inability to perform coordinated movements).

 

3) Posterior cerebral artery (PCA) territory:

The PCA supplies blood to the occipital lobes and part of the temporal lobes of the brain. The clinical features of a stroke in this territory include:

• Homonymous hemianopsia (loss of vision in half of the visual field).
• Visual hallucinations.
• Memory loss.
• Contralateral hemisensory loss.

 

4) Basilar artery territory:

The basilar artery supplies blood to the brainstem, cerebellum, and occipital lobes. The clinical features of a stroke in this territory include:

• Vertigo, nausea, vomiting, and difficulty with balance and coordination
• Cranial nerve abnormalities (e.g., facial weakness, difficulty swallowing or speaking, double vision)
• Hemiplegia or hemisensory loss affecting both sides of the body
• Coma or altered consciousness

 

5) Lacunar strokes:

Lacunar strokes are small, localized strokes that occur in the deep structures of the brain. The clinical features of a lacunar stroke depend on the specific area of the brain affected and may include:

• Pure motor hemiparesis (weakness or paralysis of one side of the body, without sensory or language deficits).
• Ataxic hemiparesis (weakness or paralysis of one side of the body, with difficulty with balance and coordination).
• Pure sensory stroke (loss of sensation on one side of the body).
• Dysarthria (difficulty speaking).
• Clumsy hand syndrome (weakness or clumsiness of the hand and arm).

It’s important to note that the clinical features of stroke can vary from person to person, and some people may not experience all of the symptoms listed above. If you or someone you know is experiencing symptoms of a stroke, seek medical attention immediately.

 

The circulatory system of the body is responsible for the transportation of blood, nutrients, oxygen, and waste products throughout the body. The system is divided into two parts: the systemic circulation and the pulmonary circulation.

The systemic circulation supplies blood to the body’s tissues and organs, and it is further divided into the anterior and posterior circulation. The anterior circulation refers to the blood vessels that supply blood to the front part of the brain, while the posterior circulation refers to the vessels that supply blood to the back part of the brain. Here are the major blood vessels in both anterior and posterior circulation and the territories they supply:

a) Anterior Circulation:

• Internal carotid artery: This artery supplies blood to the anterior part of the brain, including the frontal, temporal, and parietal lobes.
• Anterior cerebral artery: This artery supplies blood to the medial aspect of the frontal and parietal lobes, including the corpus callosum.
• Middle cerebral artery: This artery supplies blood to the lateral aspect of the frontal, parietal, and temporal lobes, including the primary motor and sensory cortices.

 

b) Posterior Circulation:

• Vertebral arteries: These arteries arise from the subclavian arteries and enter the skull through the foramen magnum, where they join to form the basilar artery. They supply blood to the medulla, pons, cerebellum, and posterior part of the cerebral hemispheres.
• Basilar artery: This artery is formed by the joining of the two vertebral arteries and supplies blood to the brainstem, cerebellum, and occipital lobes.
• Posterior cerebral artery: This artery supplies blood to the occipital lobe and the medial aspect of the temporal lobe, including the hippocampus.

It is worth noting that there are numerous smaller blood vessels that also play a significant role in supplying blood to various parts of the brain. Additionally, the brain is a highly complex and dynamic organ, and the blood supply can vary from person to person.

 

a) Ischemic stroke occurs when a blood clot or plaque buildup blocks a blood vessel in the brain, leading to decreased blood flow and oxygen supply to brain cells. The most common etiology of ischemic stroke is atherosclerosis, a condition where fatty deposits (plaque) accumulate on the walls of blood vessels.

Other etiologies of ischemic stroke include:

• Embolic stroke: Blood clots or debris that originate elsewhere in the body, such as the heart, break off and travel to the brain, blocking a blood vessel.
• Small vessel disease: Damage to the small blood vessels in the brain due to high blood pressure, diabetes, or other conditions.

 

b) Hemorrhagic stroke occurs when a blood vessel in the brain ruptures, causing bleeding into the brain tissue or the space around the brain. The most common etiology of hemorrhagic stroke is high blood pressure, which can weaken blood vessel walls and make them more prone to rupture.

Other etiologies of hemorrhagic stroke include:

• Aneurysms: Weak spots in blood vessel walls that can bulge and eventually burst.
• Arteriovenous malformations (AVMs): Abnormal tangles of blood vessels that can rupture and bleed.
• Trauma: Head injury or other trauma that can cause bleeding in the brain.

 

Tissue plasminogen activator (t-PA) is a medication used in the management of acute stroke, particularly in ischemic stroke. It works by dissolving blood clots that cause the stroke, allowing blood to flow more freely to the affected area of the brain.

The use of t-PA is time-sensitive, and it is critical that the medication is administered as soon as possible after the onset of symptoms, typically within 3-4.5 hours. This is because the longer the time between the onset of symptoms and treatment, the greater the risk of complications, such as bleeding in the brain.

To use t-PA safely, it is necessary to first confirm the diagnosis of ischemic stroke through a brain scan, such as a CT or MRI. The patient must also meet specific criteria, including no evidence of bleeding or other contraindications to the medication.

Additionally, the administration of t-PA requires close monitoring by healthcare professionals, as there is a risk of bleeding and other side effects. Patients receiving t-PA may need to be hospitalized for several days and receive frequent monitoring of their vital signs, blood tests, and neurological status.

In summary, t-PA plays a crucial role in the management of acute stroke, but its use requires careful consideration and monitoring to ensure its safety and effectiveness.

 

Secondary prevention of stroke involves taking steps to prevent a second stroke from occurring in someone who has already had a stroke or transient ischemic attack (TIA). The major venues of secondary prevention of stroke include:

1. Medications: Medications are commonly used to help prevent a second stroke. This may include antiplatelet drugs (such as aspirin or clopidogrel), anticoagulants (such as warfarin or dabigatran), and cholesterol-lowering drugs (such as statins). Blood pressure-lowering medications are also important for reducing the risk of stroke.
2. Lifestyle modifications: Certain lifestyle modifications can help prevent a second stroke. These may include quitting smoking, maintaining a healthy weight, following a healthy diet, exercising regularly, and limiting alcohol intake.
3. Management of underlying medical conditions: Underlying medical conditions such as high blood pressure, diabetes, and atrial fibrillation should be effectively managed to reduce the risk of stroke. This may involve medication, lifestyle modifications, and regular monitoring.
4. Carotid endarterectomy: For people with significant narrowing of the carotid arteries in the neck, a surgical procedure called carotid endarterectomy may be recommended. This involves removing the plaque buildup from the carotid artery to improve blood flow and reduce the risk of stroke.
5. Transcatheter PFO closure: In some cases, a small hole in the heart known as a patent foramen ovale (PFO) may be present, which can increase the risk of stroke. Transcatheter PFO closure is a minimally invasive procedure that involves inserting a small device into the heart to close the hole and reduce the risk of stroke.

It’s important to note that the best approach to secondary prevention of stroke may vary depending on the individual’s specific medical history and risk factors. A healthcare professional can provide personalized recommendations for reducing the risk of a second stroke.

 

Here are some common complications associated with stroke and ways to prevent them:

1. Paralysis or Weakness: Stroke can cause paralysis or weakness on one side of the body. To prevent this, physical therapy and rehabilitation are important to help improve strength, flexibility, and range of motion.
2. Speech and Language Impairment: Stroke can cause difficulty in speaking or understanding language. Speech therapy can help improve communication and language skills.
3. Cognitive Impairment: Stroke can cause cognitive impairment such as memory loss, difficulty with problem-solving, and reduced attention span. Brain training exercises, memory games, and cognitive therapy can help improve cognitive function.
4. Swallowing Problems: Stroke can cause difficulty in swallowing, which can lead to malnutrition, dehydration, and aspiration pneumonia. To prevent this, a speech therapist can evaluate and provide therapy to improve swallowing function.
5. Emotional Distress: Stroke can cause emotional distress such as depression, anxiety, and mood swings. Counseling, medication, and support groups can help manage emotional distress.
6. Blood Clots: Stroke survivors are at an increased risk of developing blood clots, which can lead to another stroke. To prevent this, medications such as antiplatelet or anticoagulant drugs may be prescribed.
7. Pressure Sores: Stroke survivors who have difficulty moving or are bedridden are at an increased risk of developing pressure sores. To prevent this, frequent repositioning, proper nutrition, and skin care are important.

It is important to work closely with healthcare professionals to prevent and manage complications associated with stroke. Regular check-ups, medication compliance, and healthy lifestyle choices can also help reduce the risk of stroke and its complications.