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According to the Centers for Disease Control and Prevention (CDC), over 795,000 people in the United States have a stroke every year, and around 610,000 are first strokes.

In 2019, stroke was the second leading cause of mortality globally, accounting for 11% of deaths.

There are three main types of stroke. The first and most common, accounting for 87% of cases, is an ischemic stroke. It occurs when blood flow through the artery that supplies oxygen to the brain becomes blocked.

The second is a hemorrhagic stroke, caused by a rupture in an artery in the brain, which in turn damages surrounding tissues.

The third type of stroke is a transient ischemic attack (TIA), which is sometimes called a “ministroke.” It happens when blood flow is temporarily blocked to the brain, usually for no more than 5 minutes.

While stroke is very common, it is often misunderstood. To help us dispel myths on the topic and improve our understanding, we got in touch with Dr. Rafael Alexander Ortiz, chief of Neuro-Endovascular Surgery and Interventional Neuro-Radiology at Lenox Hill Hospital.

Although stroke risk is linked to cardiovascular risk factors, strokes happen in the brain, not the heart.

“Some people think that stroke is a problem of the heart,” Dr. Ortiz told MNT. “That is incorrect. A stroke is a problem of the brain, caused by the blockage or rupture of arteries or veins in the brain, and not the heart.”

Some people confuse stroke with a heart attack, which is caused by a blockage in blood flow to the heart, and not the brain.

“The most common risk factors [for stroke] include hypertension, smoking, high cholesterol, obesity, diabetes, trauma to the head or neck, and cardiac arrhythmias,” said Dr. Ortiz.

Many of these risk factors can be modified by lifestyle. Exercising regularly and eating a healthy diet can reduce risk factors such as hypertension, high cholesterol, obesity, and diabetes.

Other risk factors include alcohol consumption and stress. Working to reduce or remove these lifestyle factors may also reduce a person’s risk of stroke.

Single-gene disorders such as sickle cell disease increase a person’s risk for stroke.

Genetic factors including a higher risk for high blood pressure and other cardiovascular risk factors may also indirectly increase stroke risk.

As families are likely to share environments and lifestyles, unhealthy lifestyle factors are likely to increase stroke risk among family members, especially when coupled with genetic risk factors.

The most common symptoms for stroke form the acronym “F.A.S.T.“:

  • F: face dropping, when one side of the face becomes numb and produces an uneven “smile”
  • A: arm weakness, when one arm becomes weak or numb and, when raised, drifts slowly downward
  • S: speech difficulty, or slurred speech
  • T: time to call 911

Other symptoms of stroke include:

  • numbness or weakness in the face, arm, leg, or one side of the body
  • confusion and trouble speaking or understanding speech
  • difficulty seeing in one or both eyes
  • difficulty walking, including dizziness, loss of balance and coordination
  • severe headaches without a known cause

“There is an incorrect belief that strokes are irreversible and can’t be treated,” explained Dr. Ortiz.

“Emergency treatment of a stroke with injection of a clot busting drug, minimally invasive mechanical thrombectomy for clot removal, or surgery can reverse the symptoms of a stroke in many patients, especially if they arrive to the hospital early enough for the therapy (within minutes or hours since the onset of the symptoms),” he noted.

“The longer the symptoms last, the lower the likelihood of a good outcome. Therefore, it is critical that at the onset of stroke symptoms — ie. trouble speaking, double vision, paralysis or numbness, etc — an ambulance should be called (911) for transport to the nearest hospital,” he continued.

Research also shows that those who arrive within 3 hours of first experiencing symptoms typically have less disability 3 months afterward than those who arrived later.

Age is a significant risk factor for stroke. Stroke risk doubles every 10 years after age 55. However, strokes can occur at any age.

One study examining healthcare data found that 34% of stroke hospitalizations in 2009 were under age 65.

A review in 2013 points out that “approximately 15% of all ischemic strokes occur in young adults and adolescents.”

The researchers noted that stroke risk factors including hypertension, diabetes, obesity, lipid disorders, and tobacco use were among the most common co-existing conditions among this age group.

Not all strokes have symptoms, and some research suggests that symptom-free strokes are far more common than those with symptoms.

One study found that out of the over 11 million strokes in 1998, 770,000 presented symptoms, whereas close to 11 million were silent.

Evidence of these so-called silent strokes appears on MRI scans as white spots from scarred tissue following a blockage or ruptured blood vessel.

Often, silent strokes are identified when patients receive MRI scans for symptoms including headaches, cognitive issues, and dizziness.

Although they occur without symptoms, they should be treated similarly to strokes with symptoms. Silent strokes put people at risk of future symptomatic strokes, cognitive decline, and dementia.

“The term ministroke has been used incorrectly as some think that it is related to small strokes that carry low risk,” said Dr. Ortiz. “That statement is incorrect, as a ministroke is a transient ischemic attack (TIA).”

“It is not a small stroke, but a premonition that a large stroke can occur. Any symptom of acute stroke, transient or persistent, needs emergency workup and management to prevent a devastating large stroke,” he added.

Stroke is a leading cause of long-term disability, but not everyone who has a stroke will experience paralysis or weakness. Research shows that stroke leads to reduced mobility in over half of stroke survivors aged 65 and over.

However, the long-term impacts of stroke vary on many factors, such as the amount of brain tissue affected and the area affected. Damage to the left brain, for example, will affect the right side of the body and vice versa.

If the stroke occurs in the left side of the brain, effects may include:

  • paralysis on the right side of the body
  • speech and language problems
  • slow and cautious behavior
  • memory loss.

If it affects the right side of the brain, paralysis may also occur, this time on the left side of the body. Other effects may include:

  • vision problems
  • quick and inquisitive behavior
  • memory loss.

Recovery from stroke can take months, if not years. However, many may not fully recover. The American Stroke Association says that among stroke survivors:

  • 10% will make an almost complete recovery
  • another 10% will require care in a nursing home or another long-term facility
  • 25% will recover with minor impairments
  • 40% will experience moderate to severe impairments

Research suggests there is a critical time window between 2–3 months after stroke onset, during which intensive motor rehabilitation is more likely to lead to recovery. Some may also be able to spontaneously recover during this period.

Beyond this window, and beyond the 6-month mark, improvements are still possible although are likely to be significantly slower.