Types Of Strokes, Complications And Risk Factors

Written by Oluwalana Toluwalope, MD | Published on September 08, 2021
Medically reviewed by Ajidahun Olusina, MD

Strokes have been the subject of intense medical study for decades. Health professionals have over the years, classified stroke into three main types. These are:

  • Ischemic stroke.
  • Haemorrhagic stroke.
  • Transient ischemic attack (TIA) also known as a mini-stroke

Ischemic stroke

An ischemic stroke occurs when a blood clot obstructs the flow of blood to the brain. Many factors contribute to this blood clot including a condition known as atherosclerosis (atherosclerosis occurs when there is a build-up of fatty deposits on the inner lining of a blood vessel). A portion of fatty deposits can break off and block blood flow to the brain.

Ischemic stroke is similar to a heart attack, where a blood clot blocks blood flow to a portion of the heart, however, unlike heart attack - blood flow to the brain is blocked. An ischemic stroke can be embolic (the blood clot can travel from another part of the body to the brain.

It should be noted that the blood clot that causes an ischemic stroke requires prompt medical attention to help get the blood clot out of the blocked blood vessel that transports blood to the brain. Although our body mechanisms will fight to eradicate the blood clot, urgent medical attention is needed.

Research has shown over the years that about 15 percent of embolic strokes are due to atrial fibrillation (a condition that occurs when the heart beats irregularly).

Types of Ischemic Stroke

There are two main types of ischemic stroke:

  • Thrombotic stroke. A thrombotic stroke is caused by a blood clot that forms in an artery that supplies blood to the brain.
  • Embolic stroke. An embolic stroke occurs when a clot forms somewhere else in the body and travels through the blood vessels to the brain. This blood clot gets stuck there and stops the flow of blood to the brain.

Risk Factors of Ischemic Stroke

An individual is more likely to have an ischemic stroke if they:

  • Adults over the age of 60
  • High blood pressure, heart disease, high cholesterol, or diabetes, are all risk factors
  • Irregular heartbeat
  • Lifestyles such as smoking
  • Family history of strokes (some genetic clotting factors)

Complications of Ischemic Stroke

A number of complications can arise from having an ischemic stroke. Studies show that stroke causes damage to the brain cells and the more the damage caused by the stroke, the more health complications for the patient. It is therefore important to get medical help as soon as possible as this can help to reduce the risk of complications such as:

  • Fluid build-up, swelling and bleeding in the brain
  • Seizures
  • Memory loss
  • Difficulty understanding certain things
  • Difficulty in swallowing

Haemorrhagic Stroke

A haemorrhagic stroke results when a blood vessel in the brain ruptures or breaks; thus, causing blood to spill into the surrounding tissues.

Causes of Haemorrhagic Stroke

There are two potential causes of haemorrhagic stroke:

Aneurysm: Aneurysms are balloon-like bulges in an artery that can stretch and burst. Haemorrhagic stroke can occur when an aneurysm ruptures, resulting in a bleed. Most aneurysms will appear after the age of 40. Many people with aneurysms do not observe symptoms. An aneurysm can be congenital or hereditary, or it can develop due to risk factors like:

  • High blood pressure
  • Smoking
  • Heavy alcohol intake
  • Head trauma

Arteriovenous malformation: This involves rupturing of an abnormally formed blood vessel. Most people with an arteriovenous malformation are born with it.

The misshapen blood vessel may rupture or bleed, causing a haemorrhagic stroke.

Occasionally, a haemorrhagic stroke can occur due to a sudden blood vessel injury which may be caused by:

  • Whiplash
  • Head trauma
  • Holding the head in an unusual position
  • Very high blood pressure levels can cause weakening of the small blood vessels in the brain and result in bleeding into the brain as well.


Risk Factors of Haemorrhagic Stroke

An individual is more likely to have a haemorrhagic stroke if they're:

  • Adults over the age of 65
  • Uncontrolled high cholesterol, high blood pressure, or diabetes
  • Obesity
  • Personal or family history of stroke
  • Smoking
  • Unhealthy eating habits

Complications of Haemorrhagic Stroke

Some of these complications have been known to occur in situations where patients suffering from haemorrhagic stroke do not get access to prompt healthcare:

  • Seizures
  • Memory and thinking problems
  • Heart problems
  • Swallowing problems and trouble eating and drinking
  • Permanent neurologic disability

While the aforementioned strokes are the main types of strokes, there are other types of strokes also. Let's take a look at them.

Transient Ischemic Attack

A Transient Ischemic Attack (TIA) is a medical emergency that occurs when blood flow to the brain is blocked, but only for a short time, usually not more than 5 minutes. TIA is sometimes referred to as a “mini-stroke” and it usually occurs as a warning sign of a future stroke.  

Most of the time, there is no way to know in the beginning whether symptoms are from a TIA or from a major type of stroke. Research shows that more than one-third of people who suffer from a TIA and do not have access to treatment may suffer a major stroke within a year as timely recognition and treatment of TIAs can lower the risk of having a major stroke.

Risk Factors For Transient Ischemic Attack

Risk factors for a Transient ischemic attack include:

  • High blood pressure
  • High cholesterol
  • Diabetes
  • Heart disease
  • Obesity
  • Smoking
  • Family history of strokes
  • Atrial fibrillation

Brain Stem Stroke

The effect of a stroke on the brain depends on which part of the brain suffers damage, and to what degree. The brain stem controls breathing, heartbeat, and blood pressure, speech, swallowing, hearing, and eye movements.

Impulses sent by other parts of the brain travel through the brain stem to various parts of the body. The human body is therefore dependent on the brain stem function for survival.

A brain stem stroke threatens vital bodily functions, making it a life-threatening condition.

Brain stem stroke can affect either one side or both sides of the body. However, both side of the body can be affected when there is bilateral stroke of the pons, not the midbrain and or medulla. Thus, leaving the patient in a “locked-in” state where they are unable to speak or move below the neck.

Symptoms of Brain Stem Stroke

Recognizing a brain stem stroke can be hard as patients may have some symptoms without the hallmark sign of weakness on one side of the body. Symptoms of brain stem stroke include:

  • Vertigo, dizziness and loss of balance
  • Double vision
  • Slurred speech
  • Passing out
  • Trouble with blood pressure and breathing
  • “Locked-in” syndrome (when patients can only move their eyes).

Causes of Brain Stem Stroke

  • Blood clots
  • Haemorrhages
  • Injury to an artery due to sudden head or neck movements (occurs on rare occasions)

Risk Factors of Brain Stem Stroke

  • Smoking
  • High blood pressure
  • Diabetes
  • Atrial fibrillation
  • Heart Disease

 Silent Stroke

A silent stroke can occur when blood supply to a part of the brain is suddenly cut off, depriving the brain of oxygen and damaging brain cells. Silent strokes[3] have no easy-to-recognize symptoms or are not remembered by the patients. They, however, cause permanent damage to the brains of the patient. An individual may have memory problems if more than one silent stroke has been experienced. They are also prone to more severe strokes over time.

A silent stroke is often hard to recognize because it disrupts blood supply to a part of the brain that does not control any visible functions like speaking or moving. The way most people find out they had a silent stroke is when they have an MRI or CT scan for another condition and doctors notice that small areas of the brain have been damaged. The scan image will show white spots or lesions where the brain cells have stopped functioning. Thus, confirming the occurrence of a silent stroke.

Signs of Silent Stroke

They are so subtle that they are often mistaken for signs of ageing. Some of these signs are:

  • balance problems
  • frequent falls
  • urine leakage
  • sudden mood swings
  • decreased ability to think

Damage done to brain cells because of silent stroke is permanent and cannot be reversed. However, healthy parts of your brain may take over the functions that used to be performed by the areas that have been damaged in some cases.

Complications of a Silent stroke

Silent strokes generally affect only a small area of the brain and symptoms are hardly noticeable. If an individual experiences several silent strokes, some neurological symptoms will be noticed (such as memory loss, or difficulty concentrating).

Research has shown over the years that silent strokes are fairly common. Also, a third of people over the age of 70 have had at least one silent stroke in their lifetime.

Recently, researchers have confirmed that having multiple silent strokes can put an individual at risk for vascular dementia (also known as multi-infarct dementia). This can cause symptoms like:

  • memory problems
  • emotional issues
  • changes to walking posture
  • indecisiveness
  • losing bowel and bladder control

Causes of silent stroke

  • blood clots
  • high blood pressure
  • narrowed arteries
  • high cholesterol
  • diabetes

Symptoms of Silent Stroke

A silent stroke often has no noticeable symptoms.


A stroke can be life-threatening if not detected on time. If you have symptoms and signs highlighted in this article – please consult your doctor. If detected, proper care and following the doctors’ guidelines and care will aid either the recovery and or management of the stroke.