Diabetic neuropathy is a type of nerve damage that can occur if you have diabetes. High blood sugar (glucose) can injure nerves throughout your body. Diabetic neuropathy most often damages nerves in your legs and feet.
Depending on the affected nerves, symptoms of diabetic neuropathy can range from pain and numbness in your legs and feet to problems with your digestive system, urinary tract, blood vessels and heart. Some people have mild symptoms. But for others, diabetic neuropathy can be quite painful and disabling.
Diabetic neuropathy is a common and serious complication of diabetes. But you can often prevent diabetic neuropathy or slow its progress with tight blood sugar control and a healthy lifestyle.
There are four main types of diabetic neuropathy. You can have one or more than one type of neuropathy. Your symptoms will depend on the type you have and which nerves are affected. Usually, symptoms develop gradually. You may not notice anything wrong until considerable nerve damage has occurred.
Peripheral neuropathy is the most common type of diabetic neuropathy. It affects the feet and legs first, followed by the hands and arms. Signs and symptoms of peripheral neuropathy are often worse at night, and may include:
- Numbness or reduced ability to feel pain or temperature changes
- Tingling or burning sensation
- Sharp pains or cramps
- Increased sensitivity to touch — for some people, even the weight of a bedsheet can be painful
- Muscle weakness
- Loss of reflexes, especially in the ankle
- Loss of balance and coordination
- Serious foot problems, such as ulcers, infections, and bone and joint pain
The autonomic nervous system controls your heart, bladder, stomach, intestines, sex organs and eyes. Diabetes can affect nerves in any of these areas, possibly causing:
- A lack of awareness that blood sugar levels are low (hypoglycemia unawareness)
- Bladder problems, including urinary tract infections or urinary retention or incontinence
- Constipation, uncontrolled diarrhea or both
- Slow stomach emptying (gastroparesis), causing nausea, vomiting, bloating and loss of appetite
- Difficulty swallowing
- Increased or decreased sweating
- Problems controlling body temperature
- Changes in the way your eyes adjust from light to dark
- Increased heart rate at rest
- Sharp drops in blood pressure after sitting or standing that may cause you to faint or feel lightheaded
- Erectile dysfunction
- Vaginal dryness
- Decreased sexual response
Radiculoplexus neuropathy (diabetic amyotrophy)
Radiculoplexus neuropathy affects nerves in the thighs, hips, buttocks or legs. It's more common in people with type 2 diabetes and older adults. Other names for this type are diabetic amyotrophy, femoral neuropathy or proximal neuropathy.
Symptoms are usually on one side of the body, but sometimes may spread to the other side. You may have:
- Severe pain in a hip and thigh or buttock that occurs in a day or more
- Eventual weak and shrinking thigh muscles
- Difficulty rising from a sitting position
- Abdominal swelling, if the abdomen is affected
- Weight loss
Most people improve at least partially over time, though symptoms may worsen before they get better.
Mononeuropathy, or focal neuropathy, is damage to a specific nerve in the face, middle of the body (torso) or leg. It's most common in older adults. Mononeuropathy often strikes suddenly and can cause severe pain. However, it usually doesn't cause any long-term problems.
Symptoms usually go away without treatment over a few weeks or months. Your specific signs and symptoms depend on which nerve is involved. You may have pain in the:
- Shin or foot
- Lower back or pelvis
- Front of thigh
- Chest or abdomen
Mononeuropathy may also cause nerve problems in the eyes and face, leading to:
- Difficulty focusing
- Double vision
- Aching behind one eye
- Paralysis on one side of your face (Bell's palsy)
Damage to nerves and blood vessels
The exact cause likely differs for each type of neuropathy. Researchers think that over time, uncontrolled high blood sugar damages nerves and interferes with their ability to send signals, leading to diabetic neuropathy. High blood sugar also weakens the walls of the small blood vessels (capillaries) that supply the nerves with oxygen and nutrients. However, a combination of factors may lead to nerve damage, including:
- Inflammation in the nerves caused by an autoimmune response. The immune system mistakes nerves as foreign and attacks them.
- Genetic factors unrelated to diabetes may make some people more likely to develop nerve damage.
- Smoking and alcohol abuse damage both nerves and blood vessels and significantly increase the risk of infection.
Diabetic neuropathy has no known cure. The goals of treatment are to:
- Slow progression of the disease
- Relieve pain
- Manage complications and restore function