So Today we will discuss about stroke, it is one of the most common cause of disability worldwide. I will explain stroke in terms of its types, causes, risk factors, symptoms, how it can be prevented, how it is diagnosed and what are the treatment options. So do read the post till the end to get complete information about stroke.

Stroke is an abrupt interruption of blood flow to the brain due to which there is no oxygen and nutrient supply to that particular area of brain leading to the death of brain cells. Once brain cells die, they generally do not regenerate and devastating damage may occur, sometimes resulting in physical, cognitive and mental disabilities.

The interruption of blood flow can be caused either by a blockage, leading to the more common ischemic stroke, which constitutes approximately 87 percent of all stroke cases or by rupture of blood vessels in the brain, leading to the more deadly hemorrhagic stroke, which are approximately 13 percent of all stroke cases.

First we will discuss about Ischemic strokes. These often occur with little or no warning, and the results can be devastating. These are further categorized into Thrombotic type and Embolic type

• Thrombotic is the most common type of ischemic stroke. A blood clot forms inside a diseased or damaged artery in the brain resulting from atherosclerosis (cholesterol-containing deposits called plaque), blocking blood flow.
• Embolic is caused when a clot or a small piece of plaque formed in one of the arteries leading to the brain or in the heart, is pushed through the bloodstream and lodges in narrower brain arteries. The blood supply is cut off from the brain due to the clogged vessel.

There is one more entity which is called as TIA (transient ischemic attack). This is a warning sign of a possible future stroke and is treated as a neurological emergency. Common temporary symptoms include difficulty speaking or understanding others, loss or blurring of vision in one eye and loss of strength or numbness in an arm or leg.

The definition of a TIA has moved from time-based to tissue-based. A TIA typically lasts less than an hour, more often minutes. TIA can be considered as a serious warning for an impending ischemic stroke; the risk is highest in the first 48 hours following a transient ischemic attack. Even if all the symptoms resolve, it is very important that anyone experiencing these symptoms call emergency services and immediately be evaluated by a qualified physician.

Next in the list is Hemorrhagic strokes. It can also be classified into either intracerebral hemorrhage or subarachnoid hemorrhage.

• Intracerebral Hemorrhage:  Bleeding occurs from the blood vessels within the brain parenchyma. It is usually caused by hypertension (high blood pressure). In this, bleeding occurs suddenly and rapidly. There are usually no warning signs and bleeding can be severe enough to cause coma or death.

• Subarachnoid Hemorrhage bleeding occurs between the brain and the meninges (the membrane that covers the brain) in the subarachnoid space. This type of hemorrhage is often due to an aneurysm or an arteriovenous malformation (AVM). It often presents with severe headache associated with nausea & vomiting.

An aneurysm is a weakened, ballooned area on an artery wall and has a risk for rupturing. Aneurysms may be congenital (present at birth), or may develop later in life due to factors such as hypertension or atherosclerosis.

An AVM is a congenital disorder that consists of a disorderly tangled web of arteries and veins. The cause of AVM is unknown, but it is sometimes genetic or part of certain syndromes.

RISK FACTORS:

It is very essential to know the factors which increase the risk of strokes. You should try to reduce, control or even treat the risk factors so as to prevent its occurrence.

Controllable or treatable risk factors for stroke include:

• 1. High blood pressure: Blood pressure of 140/90 mm Hg or higher is the most important risk factor for stroke. It usually has no specific symptoms and no early warning signs. That is why it is important to have your blood pressure checked regularly. Controlling your blood pressure is crucial to stroke prevention.
• 2. Diabetes: Diabetes is a chronic condition in which the body is unable to utilise blood sugar. A person with diabetes is around twice as likely to have a stroke as someone of the same gender and age, who doesn’t have diabetes. This is because the high blood sugar levels contribute to the development of atherosclerosis (narrowing of arteries). It is very important that diabetes be kept under control.
• 3. High blood cholesterol: A high level of total cholesterol in the blood (240 mg/dL or higher) is a major risk factor for heart disease, which raises your risk of stroke. Low levels (less than 40 mg/dL) of HDL (good) cholesterol also may increase stroke risk

• 4. Smoking: Smoking can double or even quadruple your risk of stroke. Some of the chemicals in cigarette smoke (such as nicotine and carbon monoxide) accelerate the process of atherosclerosis (narrowing of arteries). Clots are more likely to form because smoking thickens the blood and makes clotting factors, such as platelets, much more ‘sticky’. Cigarette smoke forces arteries to constrict (get narrower), which makes it harder for the thickened blood to move through the vessels.
•  5. Carotid or other artery disease: The carotid arteries in your neck, supply blood to your brain. A carotid artery narrowed by fatty deposits from atherosclerosis may become blocked by a blood clot. Carotid arteries are treated by neurosurgeons through carotid endarterectomy, a procedure in which an incision is made in the neck and plaque is removed from the artery; or carotid artery angioplasty and stenting, an endovascular procedure that requires no surgical incision in the neck.
• 6. History of TIAs: About 30 percent of strokes are preceded by one or more TIAs that can occur days, weeks or even months before a stroke.

• 7. Physical inactivity and obesity: Being inactive, obese or both can increase the risk of stroke. Getting 30 minutes of moderate exercise, five days a week can help reduce your risk of stroke.
• 8. Atrial fibrillation: People with atrial fibrillation (AF), a particular type of irregular heartbeat, are at increased risk of ischaemic stroke. This is because the inefficient pumping of the atria allows blood to stagnate and ultimately form clots in the atria. Parts of these clots may then break off, travel in the blood to the brain and block an artery, causing a stroke.
• 9. Recent research shows evidence that people receiving hormone replacement therapy (HRT) have an overall 29 percent increased risk of stroke, in particular ischemic stroke.

Uncontrollable risk factors include:

• 1. Age: People of all ages, including children, have strokes. But the older you are, the greater your risk of stroke.
• 2. Gender: Stroke is more common in men than in women. In most age groups, more men than women will have a stroke in a given year.

• 3. Heredity and race: You have a greater risk of stroke if a parent, grandparent, sister or brother has had a stroke. African Americans are at increased risk of developing stroke
• 4. Prior stroke or heart attack: If you have had a stroke, you are at much higher risk of having another one. If you have had a heart attack, you are also at higher risk of having a stroke.

SIGNS & SYMPTOMS OF STROKE:

They may vary from person to person, but usually begin suddenly.

As different parts of your brain control different parts of your body, your symptoms will depend on the part of your brain affected and the extent of the damage.

The main stroke symptoms can be remembered with the mnemonic BE FAST:

• Balance: Sudden dizziness, loss of balance or coordination.
• Eyes: Sudden trouble seeing out of one or both eyes
• Face – the face may have dropped on 1 side, the person may not be able to smile, or their mouth or eye may have drooped.
• Arms – the person may not be able to lift both arms and keep them there because of weakness or numbness in 1 arm.
• Speech – their speech may be slurred or garbled, or the person may not be able to talk at all despite appearing to be awake; they may also have problems understanding what you’re saying to them.
• Time – it’s time to call emergency services immediately if you notice any of these signs or symptoms.

So just remember that while managing a patient of stroke, you have to BE FAST

Other sign and symptoms may include:

• Complete paralysis of 1 side of the body
• confusion
• difficulty swallowing (dysphagia)
• a sudden and very severe headache resulting in a blinding pain unlike anything experienced before
• loss of consciousness

But there may be other causes of these symptoms.

So that was all about the types, causes, risk factors and the symptoms of stroke. In my next video, I will discuss about the investigations needed for diagnosis of stroke and what are the treatment options. If you liked this blogpost, share this post with your friends and comment below to discuss any doubts or anything at all.

REFERENCES:

https://www.aans.org

https://www.nhlbi.nih.gov

https://ahajournals.org

https://www.acc.org