Diabetic Neuropathy Symptoms

March 03, 2023

Overview

Diabetes can cause a type of nerve damage known as diabetic neuropathy. High blood sugar levels can harm nerves throughout the body, with the legs and feet being the most commonly affected areas. Symptoms of diabetic neuropathy vary depending on the nerves that are damaged, and may include pain and numbness in the hands, feet, and legs. This condition can also lead to complications with the digestive system, urinary tract, blood vessels, and heart. While some individuals may only experience mild symptoms, diabetic neuropathy can be extremely painful and debilitating for others.

It is estimated that up to 50% of people with diabetes may develop diabetic neuropathy, making it a serious complication of the disease. However, consistent management of blood sugar levels and a healthy lifestyle can often help prevent or slow the progression of diabetic neuropathy.

Symptoms

Diabetic neuropathy can be categorized into four main types, and it is possible to have one or more types of neuropathy. The symptoms that you experience will depend on the specific type and which nerves have been affected. Typically, symptoms will develop slowly, and it may be difficult to detect any problems until significant nerve damage has already occurred.

Peripheral neuropathy

Distal symmetric peripheral neuropathy, which is also known as this type of neuropathy, is the most prevalent form of diabetic neuropathy. The condition initially impacts the feet and legs, followed by the hands and arms. Symptoms of peripheral neuropathy typically worsen at night and may include:

Reduced ability to feel pain or temperature changes, resulting in numbness.
A burning or tingling sensation.
Cramps or sharp pains.
Muscle weakness.
Extreme sensitivity to touch, which can cause pain even from light pressure, such as from a bedsheet.
The potential for serious foot problems, such as infections, ulcers, and damage to bones and joints.

Autonomic neuropathy

The autonomic nervous system is responsible for regulating bodily functions such as blood pressure, heart rate, sweating, digestive system, bladder control, and sexual organs. Diabetes can damage nerves in any of these areas, resulting in a range of signs and symptoms, such as:

Hypoglycemia unawareness, which is a lack of awareness that blood sugar levels are low.
Orthostatic hypotension, which is a drop in blood pressure upon rising from a sitting or lying position, leading to dizziness or fainting.
Bladder or bowel dysfunction.
Gastroparesis, which is slow stomach emptying resulting in nausea, vomiting, feeling full, and loss of appetite.
Difficulty swallowing.
Changes in visual adjustments, such as from light to dark or near to far.
Excessive or insufficient sweating.
Sexual response problems, including vaginal dryness in women and erectile dysfunction in men.

Proximal neuropathy (diabetic polyradiculopathy)

Proximal neuropathy typically impacts nerves in the thighs, hips, buttocks, or legs, and can also affect the chest and abdominal area. While symptoms typically manifest on one side of the body, they may also spread to the other side. Signs and symptoms of proximal neuropathy may include:

Intense pain in the thigh, hip, or buttock region.
Weakening and atrophy of the thigh muscles.
Difficulty standing up from a seated position.
Pain in the chest or abdominal wall.

Mononeuropathy (focal neuropathy)

Mononeuropathy is characterized by damage to a single nerve, which may be located in the face, torso, arm, or leg. Symptoms of mononeuropathy may include:

Difficulty with concentration or double vision
Facial paralysis on one side of the face
Tingling or numbness in the hand or fingers
Hand weakness resulting in difficulty gripping or dropping objects
Pain in the foot or shin
Weakness causing difficulty lifting the front part of the foot (foot drop)
Pain in the front of the thigh.

When to see a doctor

If you experience any of the following symptoms, it is advisable to schedule an appointment with your healthcare provider:

An infected cut or sore on the foot that does not heal or is slow to heal.
Weakness, pain, tingling, or burning sensations in the feet or hands that interfere with daily activities or sleep.
Changes in digestion, urination, or sexual function.
Dizziness and fainting.

According to the American Diabetes Association (ADA), screening for diabetic neuropathy should commence immediately following a diagnosis of type 2 diabetes or five years after being diagnosed with type 1 diabetes. Thereafter, annual screening is recommended.

Causes

The specific cause of each type of neuropathy remains unclear. However, experts believe that diabetic neuropathy is the result of prolonged high blood sugar levels that harm nerves and disrupt their ability to transmit signals. This damage is thought to occur gradually over time. Additionally, high blood sugar weakens the walls of tiny blood vessels known as capillaries that provide nerves with oxygen and nutrients.

While anyone with diabetes can develop neuropathy, certain risk factors can increase the likelihood of nerve damage:

Poor blood sugar management. Uncontrolled blood sugar levels increase the risk of all diabetes-related complications, including nerve damage.
Duration of diabetes. The risk of diabetic neuropathy increases over time, particularly if blood sugar levels remain uncontrolled.
Kidney disease. Diabetes can harm the kidneys, leading to the release of toxins into the blood that may damage nerves.
Overweight or obesity. Individuals with a BMI of 25 or higher may have an increased risk of developing diabetic neuropathy.
Smoking. Smoking can narrow and harden arteries, decreasing blood flow to the legs and feet. This can make it difficult for wounds to heal and damage peripheral nerves.

Complications

Diabetic neuropathy can lead to several severe complications, which include:

Hypoglycemia unawareness: When blood sugar levels drop below 70 milligrams per deciliter (mg/dL) — 3.9 millimoles per liter (mmol/L), common symptoms like shakiness, sweating, and a fast heartbeat occur. However, people who have autonomic neuropathy may not experience these warning signs.
Amputation of a toe, foot, or leg: Nerve damage can cause loss of sensation in the feet, making minor cuts or injuries go unnoticed. In severe cases, infections can spread to the bone or lead to tissue death, making amputation of a toe, foot, or even a part of the leg necessary.
Urinary tract infections and urinary incontinence. When the nerves controlling the bladder are damaged, it can cause incomplete emptying of the bladder, leading to bacterial build-up and infections. Additionally, nerve damage can lead to loss of control over the muscles that release urine, causing leakage or incontinence.
Orthostatic hypotension. Damage to the nerves that regulate blood flow can disrupt the body's ability to adjust blood pressure, leading to sudden drops in blood pressure upon standing from sitting or lying down. This can result in dizziness or fainting.
Gastrointestinal issues. Diabetic neuropathy can affect the nerves in the digestive system, leading to constipation, diarrhea, or both. Gastroparesis, a condition in which the stomach empties slowly or not at all, can also occur, causing indigestion and bloating.
Sexual dysfunction. Autonomic neuropathy can damage the nerves that control sexual organs, leading to erectile dysfunction in men and difficulties with lubrication and arousal in women.
Sweating abnormalities. Nerve damage can interfere with the functioning of sweat glands, making it challenging for the body to regulate its temperature properly. This can cause excessive or decreased sweating.

Prevention

Effective management of blood sugar levels and proper foot care can help in preventing or delaying diabetic neuropathy and its associated complications.

Blood sugar management

According to the American Diabetes Association (ADA), individuals with diabetes should undergo a glycated hemoglobin (A1C) test at least two times a year. This test reflects the average blood sugar level for the preceding 2-3 months.

Although A1C goals may vary depending on the individual, for most adults, an A1C of less than 7.0% is recommended by the ADA. If your blood sugar levels exceed your goal, you may need to make modifications to your daily management, such as altering your diet or physical activity, or adjusting your medications.

Foot care

To avoid foot problems, such as sores, ulcers, and even amputation, which are common complications of diabetic neuropathy, it is recommended to have a comprehensive foot examination at least once a year. Additionally, have your health care provider examine your feet during each office visit and maintain proper foot care at home.

It is important to follow your health care provider's advice for good foot care. To ensure the health of your feet, you should:

Check your feet daily. Look for any signs of blisters, cuts, bruises, redness, swelling, cracked or peeling skin. Use a mirror or ask someone to help you examine areas that are hard to see.
Keep your feet clean and dry. Use lukewarm water and mild soap to wash your feet daily. Do not soak your feet, and dry them and the areas between your toes thoroughly.
Moisturize your feet to prevent cracking, but avoid applying lotion between your toes, which may encourage fungal growth.
Trim your toenails carefully by cutting them straight across and filing the edges smoothly. If needed, a podiatrist can assist you with this.
Wear clean and dry socks made of cotton or moisture-wicking fibers that do not have tight bands or thick seams.
Wear cushioned shoes that fit well and protect your feet, such as closed-toed shoes or slippers. Make sure your shoes fit correctly and allow your toes to move freely. A podiatrist can help you learn how to choose shoes that fit properly and prevent corns and calluses. Medicare may cover the cost of at least one pair of shoes per year if you qualify.