Diabetic Neuropathy: Cause, Risk Factors, Types and Symptoms
Having elevated blood sugar can damage our body’s nerves over time.
Diabetic neuropathy is the generic term for all diabetes-related nerve damage disorders. These disorders can affect our peripheral and autonomic nervous systems.
Peripheral nerves lie outside our brain and spinal cord. They extend through the limbs and to many sensory organs. Autonomic nerves control body movements that take place automatically such as heart beats, gland activity, and the workings of our intestines.
The most important thing to remember about diabetic neuropathy is that the best prevention, and primary means of slowing nerve damage progression, is good blood glucose control. However, about half of those who have diabetes develop neuropathy, and disciplined blood sugar monitoring does not guarantee immunity.
Cause and Risk Factors
There is constant interaction between our blood vessels and our nerves – the health of one affects the health of the other – and glucose levels affect the functioning of both. We know that blood carries oxygen and nutrients to our nerves, and high blood sugar weakens blood vessel walls, impairing blood circulation. Elevated glucose also diminishes our nerves’ capacity to transmit signals.
Some other factors influence the development of diabetic neuropathy:
- Genetics. Thanks to our genetic inheritance some of us are more susceptible to nerve damage than others.
- Inflammation. Our immune system can mistake parts of our body for foreign organisms and attack them. This is called an autoimmune response, and it can cause our nerves to become inflamed. Chronic inflammation leads to nerve damage.
- Years having diabetes. Symptoms of neuropathy are most common in individuals who have had diabetes 25 years or more.
- Kidney problems. One complication of diabetes is kidney damage. Less effective kidneys may mean more toxins in the bloodstream, and toxins contribute to nerve injury.
- Alcohol abuse and smoking. Alcohol can wreak havoc on blood sugar levels, increasing the risk of neuropathy. Smoking is known to reduce blood flow in our extremities by narrowing and hardening the arteries.
Four Types of Neuropathy and Symptoms
Not everyone with diabetic neuropathy experiences symptoms, and damage that occurs over time may not trigger symptoms until the injury is significant. Since physicians can observe signs of neuropathy before symptoms arise, regular doctor visits are important.
1. Peripheral neuropathy is the most common type of diabetic nerve damage. It may cause numbness or pain in the toes, feet, legs, hands, or arms. Other names for peripheral neuropathy are sensorimotor neuropathy and distal symmetric neuropathy. Symptoms include:
- Numbness, or lack of sensitivity to pain/temperature
- Burning, tingling, or prickling sensations
- Cramps and sharp pain
- High sensitivity to touch
- Reduced coordination and balance
2. Autonomic neuropathy damages nerves that regulate blood sugar, blood pressure, and heart rate, and may cause problems in several organs. Symptoms include:
- Hypoglycemia unawareness (not realizing your blood sugar levels are low)
- Drop in blood pressure after sitting or standing; increased heart rate
- Constipation; gastroparesis (stomach empties too slowly); trouble swallowing
- Bladder infections (bladder does not empty fully), incontinence, and sexual performance issues
- Sweat gland malfunction (no sweating, or profuse sweating)
- The eyes' pupils become less responsive to light changes; poor night vision
3. Proximal neuropathy, or diabetic amyotrophy, involves sudden pain in the hips, thighs, legs, or buttocks—typically felt on one side of the body. Proximal nerve damage is more common in diabetic seniors and those with type 2 diabetes. It is also called Radiculoplexus neuropathy. Symptoms may improve over time and include:
- Severe hip, leg, thigh, and buttock pain
- Weakened or atrophied thigh muscles
- Trouble standing from a seated position
- Possible abdominal swelling; weight loss
4. Focal or mononeuropathy affects certain nerves, usually in the head, leg, or torso. It is more common in older adults with diabetes, tends to appear suddenly, and is quite painful. However, focal neuropathy typically improves on its own—although improvement is slow—and seldom results in long-term damage. Symptoms include:
- Double vision, problems focusing, an ache behind one eye
- Bell’s palsy (paralysis on one side of the face)
- Severe pelvic or lower back pain
- Front thigh pain; pain at the inside of a foot or the outside of a shin
- Chest, stomach, or side pain
- Intense abdominal or chest pain (can be mistaken for appendicitis/heart attack)
When to See Your Doctor
See a doctor if you have a cut, sore, or infection on your foot that is not healing properly, or if you notice burning, pain, tingling, or weakness in hands or feet that disrupt sleep or daily routine. See a physician about dizziness, and changes in urination, digestion, or sexual function.
Foot sores and infections that do not heal properly and are left untreated can lead to tissue death or gangrene. This condition may require surgery and possibly amputation of the affected foot or limb. Early diagnosis and treatment can prevent this from occurring.