Abstract
Individuals with unmanaged diabetes have a much higher risk of developing peripheral neuropathy. With cases of diabetes continuing to spike around the world, more people are living with nerve damage that may progressively get worse. One of the strongest possibilities as to how diabetes may lead to peripheral neuropathy is related to any damage untreated diabetes may inflict on the blood vessels, resulting in a decreased flow of nutrients and oxygen to peripheral nerves. However, this is often mistaken for peripheral artery disease (PAD) due to their many similarities. Both these conditions are commonly associated with diabetes. Symptoms of diabetic neuropathy are plentiful, but the most common are numbness, muscle weakness, pain, and slow-healing foot or leg ulcers. These symptoms can be reduced by treating the diabetes causing it. Due to sedentary lifestyles becoming more prominent in recent years, controlling blood sugar levels plays an important role in the prevention of diabetic peripheral neuropathy.
Introduction
Peripheral neuropathy, or the damage of nerves outside of the spinal cord, is one of the most common types of neuropathy today. Though peripheral neuropathy in itself has many different subtypes as well as causes, diabetic neuropathy makes up the vast majority of diagnosed cases. Diabetes has been a much more prominent issue in the world as of late and the epidemic continues to worsen by the year. Because of this, diabetes has had a significant role in the prevalence of peripheral neuropathy in recent years. Diabetic peripheral neuropathy is considered one of the most common chronic complications of diabetes associated with both type 1 and type 2 diabetes(8) (4), often affecting primarily the lower extremities, the legs and feet, and occasionally the hands(3). Researchers have compiled plenty of information on diabetic peripheral neuropathy over the years, however, the exact cause varies per person and may remain unknown. In addition to this, how diabetes correlates to nerve damage outside of the spinal cord still has speculation surrounding it.
Background and Objectives
With over 100 different types, peripheral neuropathy is a highly studied condition that may affect people due to a wide variety of causes and risk factors, one of the most common causes being diabetic peripheral neuropathy(5). Each type has its own standard for diagnosis because of its unique symptoms and signs. As diabetes continues to be a pressing issue in the world, peripheral neuropathy is slowly growing alongside it. In 32 years, from 1990 to 2022, the number of people living with diabetes rose from 200 million to 830 million, with mortality rates progressively increasing since 2000(7). Peripheral neuropathy is a common condition as it often develops after a person’s blood sugar spikes for a prolonged period of time, and the effects of the nerve damage may be irreversible. Though it is currently unclear how exactly diabetes contributes to the development of peripheral neuropathy, this literature review will explore the most supported possibility as to how diabetes can lead to peripheral neuropathy and the effects it may have on the body as diabetic neuropathy becomes more and more of a prevalent issue in today’s society.
Research Question:
How does diabetes cause peripheral neuropathy and what are the effects associated with it?
A. The Ever-Growing Diabetes Epidemic
Diabetes, a type of endocrine disease, also referred to as diabetes mellitus, is the seventh leading cause of death in the US today and has maintained that position(5). With more sedentary lifestyles and such high availability of processed foods, especially in the West, diabetes is seen to have a drastic rise in numbers. The CDC predicts that by the year 2060, there will be a nearly 700% increase in type 2 diabetes and a 65% increase in type 1 diabetes diagnoses in young people(2). Many people, whether they are still in school or have a job, engage in a sedentary lifestyle. Office jobs are a prime example of this, providing little to no movement for employees throughout the workday. Because of this lack of full body movement and exercise, the human body ends up storing an excess of sugar in the bloodstream. If blood sugar levels remain high, a person may be diagnosed with diabetes, resulting in the numbers we see today. These numbers continue to climb each year as lifestyles shift away from focusing on health and activity.
B. Diabetes as a Cause of Peripheral Neuropathy
Due to there being over 100 subtypes of peripheral neuropathy, broken into these categories depending on a person’s symptoms: motor neuropathy, sensory neuropathy, and autonomic nerve neuropathy(4), and their nature of having no exact identifiable cause, diabetic peripheral neuropathy has no direct explanation as to how diabetes can lead to nerve damage, but there are some possibilities. One possibility is that when hyperglycemia, or high blood sugar, is left unmanaged for a long period of time, it can start to damage the blood vessels by breaking away at their inner linings(3)(1)(6). Arteries then respond by forming a layer of plaque along the inside of those pathways, in turn restricting the flow of oxygen-rich blood reaching the extremities(6). With this, nerve cells do not receive enough oxygen to function properly, leading to their damage and possibly death(3). Peripheral neuropathy should not be confused with peripheral artery disease, though they do share many characteristics. Both conditions are often caused by diabetes and are associated with damage to the blood vessels. Peripheral artery disease, or PAD, is the hardening of peripheral arteries while peripheral neuropathy is the damage of peripheral nerve cells. Because of their many similarities, both these conditions are often misdiagnosed or even completely overlooked.
C. Symptoms, Treatments, and Prevention
Diabetic peripheral neuropathy has an extensive list of possible symptoms, though a person may not experience all of the listed symptoms. A person may experience a variety of sensations, some may feel mild tingling or numbness, while others may experience severe pain and even paralysis(4). Some symptoms of diabetic peripheral neuropathy include numbness and paresthesia, burning, stabbing, or shooting pain, muscle weakness, slow-healing leg or foot ulcers, and a total loss of sensation in the feet. Symptoms often progressively worsen over time if not treated properly. Treatments often depend on the severity of symptoms, but most treatments for diabetic peripheral neuropathy are those meant for managing hyperglycemia and diabetes itself. Controlling blood sugar levels can reduce or even completely eliminate symptoms of peripheral neuropathy(1). As diabetes-related peripheral neuropathy is often a result of poor lifestyle choices or unmanaged diabetes, prevention significantly reduces the likelihood of its development. Eating healthier foods, regularly exercising, and avoiding toxins such as smoking and alcohol can lessen the risk for diabetic peripheral neuropathy(4).
Closing
Diabetes has a significant impact on the body in multiple ways, one of which is the nerve damage that may be associated with it. Diabetic peripheral neuropathy is often the result of sedentary lifestyles and unmanaged diabetes. Due to the different types of peripheral neuropathy, as well as the differences in symptoms from person to person, diabetic peripheral neuropathy may be hard to diagnose. With the condition being so similar to peripheral artery disease and because of its variants, the connection between diabetes and peripheral neuropathy has not always been clear and is still under speculation. However, the strongest possibility is related to the damage of blood vessels because of hyperglycemia, then resulting in the damage of nerve cells due to a lack of oxygen-rich blood. By understanding the effects of diabetic peripheral neuropathy and its development, the drastically high numbers of diagnoses can slowly be brought back down and bring comfort back to the lives of those living with the condition.
Written By: Yassmine G. Mamane
Works Cited
1: Catanese L. Peripheral neuropathy: Causes, symptoms, treatment, and prevention - Harvard Health. Harvard Health. Published August 19, 2024. https://www.health.harvard.edu/diseases-and-conditions/peripheral-neuropathy-causes-symptoms-treatment-and-prevention
2: CDC. CDC Newsroom. CDC. Published January 1, 2016. https://www.cdc.gov/media/releases/2022/p1229-future-diabetes-surge.html
3: Diabetic Neuropathy: Peripheral Neuropathy, Symptoms, Treatment. Cleveland Clinic. Published August 28, 2024. https://my.clevelandclinic.org/health/diseases/21621-diabetic-neuropathy
4: John Hopkins Medicine. Peripheral Neuropathy. John Hopkins Medicine. Published 2019. https://www.hopkinsmedicine.org/health/conditions-and-diseases/peripheral-neuropathy
5: Sapra A, Bhandari P. Diabetes. PubMed. Published June 21, 2023. https://www.ncbi.nlm.nih.gov/books/NBK551501/
6: Why diabetes can damage your blood vessels, and how to know if you’re at risk | Society for Vascular Surgery. vascular.org. Published November 24, 2019. https://vascular.org/news-advocacy/articles-press-releases/why-diabetes-can-damage-your-blood-vessels-and-how-know-if
7: World Health Organization. Diabetes. World Health Organization. Published November 14, 2024. https://www.who.int/news-room/fact-sheets/detail/diabetes
8: Yang K, Wang Y, Li YW, et al. Progress in the treatment of diabetic peripheral neuropathy. Biomedicine & Pharmacotherapy = Biomedecine & Pharmacotherapie. 2022;148:112717. doi:https://doi.org/10.1016/j.biopha.2022.112717
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