Neural Conditions: Stroke

Written by: Caroline Kim

July 6, 2024

Our brain, the control center of our bodies, is very complex and powerful. Today, we begin a series focused on the topic of neural conditions. There are so many unique topics that we can cover, but we’ll start with one of the more common medical conditions known as a stroke. According to the CDC, “A stroke, sometimes called a brain attack, occurs when something blocks blood supply to part of the brain or when a blood vessel in the brain bursts… A stroke can cause lasting brain damage, long-term disability, or even death” (CDC. “About Stroke.”). 

There are two main types of strokes: an ischemic stroke and a hemorrhagic stroke. The ischemic stroke is the more common case, and occurs when there is a blockage in the brain's blood vessels due to something such as a blood clot. The latter occurs when arteries in the brain rupture, causing brain bleeds, pressuring the brain cells and ultimately damaging them (CDC. “About Stroke.”). Another notable condition is the TIA (transient ischemic attack/”mini stroke”), where blood flow in the brain is very temporarily blocked; over 33% of those who have a TIA and do not receive treatment subsequently experience a major stroke within a year (CDC. “About Stroke.”). In other words, a TIA is a key indicator that the individual may experience a major stroke in the near future. After experiencing a stroke, there are several complications that may ensue: paralysis, difficulty eating, difficulty talking, memory loss, impaired judgment/thinking, emotional/lifestyle changes, and bodily pain (Mayo Clinic Staff. “Stroke.”). 

As provided by Mayo Clinic, symptoms that are experienced during a stroke include difficulty speaking/understanding, numbness in the face/arms/legs, vision problems, headaches, and difficulty walking; immediate medical care should be sought if one side of the person droops (when smiling), paralysis, or slurred speech (Mayo Clinic Staff. “Stroke.”). In 2021, 1 in 6 deaths from cardiovascular disease was due to stroke, About 185,000 strokes—nearly 1 in 4—are in people who have had a previous stroke, and Stroke is a leading cause of serious long-term disability (CDC. “Stroke Facts.”). This being said, strokes are a very serious condition and preventative measures as well as being able to identify stroke symptoms are crucial.

As always, we will dive into the chemistry and biology behind strokes and what occurs in the body during a stroke. In ischemic strokes, “interrupted cerebral blood flow depletes the brain of oxygen and glucose, which leads to disrupted ATP synthesis and energy deficiency, as well as impaired ion homeostasis and acid-base imbalance… result in cerebral neuropathological changes, such as brain edema, neuroinflammation, and neural cell death, eventually underpinning severe neurological deficits” (Qin). Following an ischemic stroke, the reduction of cerebral blood flow limits the glucose and oxygen availability most notably in neurons; in conjunction, “may eventually lead to cellular excitotoxicity and mitochondrial dysfunctions, which serve as the initiating session of ischemia-induced damage and subsequently cause other cascade of injuries” (Qin). Excitotoxicity and signaling pathways are major factors accounting for the science of a stroke, and for more in depth reviews, please reference source (4) and the home page for helpful links. 

Certain factors that increase an individual’s risk for stroke such as people over the age of 55, Men, and those of African American/Hispanic background. More factors include the following: lack of exercise, obesity, drinking in excess, drugs, smoking, high blood pressure, diabetes, high cholesterol, heart disease, and family history of stroke (Mayo Clinic Staff. “Stroke.”). This being said, counteracting some of these variable factors such as being more active and reducing alcohol intake can help prevent stroke. Antiplatelet drugs and anticoagulants (blood thinning medications) may also be implemented to prevent stroke/more strokes (Mayo Clinic Staff. “Stroke.”). 

Sources:

1. CDC. “About Stroke.” Centers for Disease Control and Prevention, 15 May 2024, www.cdc.gov/stroke/about/index.html#:~:text=A%20stroke%2C%20sometimes%20called%20a,brain%20become%20damaged%20or%20die. Accessed 06 July 2024. 

2. Mayo Clinic Staff. “Stroke.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 30 Apr. 2024, www.mayoclinic.org/diseases-conditions/stroke/symptoms-causes/syc-20350113. Accessed 06 July 2024. 

3. CDC. “Stroke Facts.” Centers for Disease Control and Prevention, 14 May 2024, www.cdc.gov/stroke/data-research/facts-stats/index.html. Accessed 06 July 2024. 

4. Qin, Chuan, et al. “Signaling Pathways Involved in Ischemic Stroke: Molecular Mechanisms and Therapeutic Interventions.” Nature News, Nature Publishing Group, 6 July 2022, www.nature.com/articles/s41392-022-01064-1. Accessed 06 July 2024.