Neuropathy can affect any nerve in the body, but especially the nerves of the ganglia, the outside of the skull, the spinal cord, and those that impact the functioning of fundamental organs, such as the heart, bladder, intestines, and stomach.
Problems can occur in the nerves that control the periphery, or outside, of the body, such as the feet and hands, those that control the automatic functions of the body, such as heart rate and digestion, or just one or a small group of nerves. Different nerves are affected in different ways.
Around 60 percent to 70 percent of people with diabetes develop diabetic neuropathy, but symptoms may take 10 to 20 years to appear. The highest rates of neuropathy are found in patients who have been diagnosed with diabetes for 25 years or more.
Uncontrolled diabetes can lead to nerve damage.
There are four main types of neuropathy, and they are:
- Peripheral neuropathy, which affects the feet and hands, is the most common form of diabetic neuropathy
- Autonomic neuropathy, affecting the nerves that control the involuntary functions of the body, like digestion
- Proximal neuropathy, which affects the legs
- Focal neuropathy, in which damage can occur in any nerve or any group of nerves.
The symptoms of neuropathy depend on the nerves affected. A range of problems is associated with diabetic neuropathy. These include cardiovascular issues, intestinal problems such as constant diarrhea, nausea, and vomiting, weakness, muscle pain, and paralysis.
The signs and symptoms of diabetic neuropathy depend on which nerves are affected, and they usually take several years to appear.
Signs and symptoms of peripheral neuropathy include:
- Numbness, pain, tingling and (or) burning sensations starting in the extremities and continuing up the legs or arms
- Not being able to feel heat, cold or any injury
- Loss of balance
- Charcot's joint, in which a joint breaks down because of a problem with the nerves. This often affects the feet.
Signs and symptoms of autonomic neuropathy include:
- Heartburn and bloating
- Nausea, constipation or diarrhea
- Not feeling low blood sugar levels (hypoglycemic unawareness)
- Difficulty speaking or swallowing
- Feeling full when eating small amounts of food
- Vomiting a few hours after eating
- Orthostatic hypotension, or feeling light-headed and dizzy when standing up
- Faster heart rate than normal
- Excessive sweating, even when temperature is cool or the individual is at rest
- Bladder problems, for example, difficulty in emptying the bladder completely when urinating, leading to incontinence
- Sexual dysfunction in men
- Sexual problems in women with vaginal dryness and inability to experience orgasm
- Dysesthesia, when the patient's sense of touch is distorted
- Significant drooping of the face and eyelids
- Muscle contractions and weakness.
Proximal neuropathy can lead to pain in the lower body, often on one side, and weakness in the legs.
Symptoms of focal neuropathy vary widely, depending on the nerve affected.
People with diabetic neuropathy often do not realize they are affected until the symptoms are more advanced.
A physician will carry out a physical exam and do a foot exam to check for:
- Ankle reflexes
- Loss of sensation
- Changes in skin texture
- Changes in skin color
If the doctor suspects diabetic neuropathy, the patient may undergo some diagnostic tests, such as an electromyogram (EMG), which records the electrical activity in the muscles, or a nerve conduction velocity test (NCV), which records the speed at which induced signals pass through the nerves.
Diabetic neuropathy worsens over time. The first step for neuropathy is to get blood sugars under control and to manage high blood pressure and cholesterol levels.
Keeping blood sugar under control helps to prevent diabetic neuropathy.
If diabetes is well controlled, and glucose levels are kept within a healthy range throughout the day, the risks of diabetic neuropathy can be minimized. A very important part of treatment focuses on reducing pain and controlling some of the symptoms.
Some drugs and physical therapy, as well as other treatments, can help to control the pain caused by diabetic neuropathy.
Drug classes that can help control pain include opioids and opioid-like drugs, anticonvulsant drugs, and tricyclic antidepressants.
Other types of antidepressants, such as serotonin-norepinephrine inhibitors are commonly used to target the painful symptoms of diabetic neuropathy, and they may help patients with depression.
Physical therapy, used in combination with medications, can help relieve pain and reduce the risk of drug dependency. Some physical therapies can alleviate pain, burning, and tingling sensations in the legs and feet. Physical therapy may help patients with muscle cramps, muscle weakness, and sexual dysfunction.
Electrical nerve stimulation is painless, and it may help to relieve feelings of stiffness and enhance the healing of foot ulcers.
Gait training means relearning how to walk. It helps to prevent and stabilize foot complications, such as ulcers. Gait training is crucial for people who are using a prosthesis because they have lost limbs due to diabetic neuropathy. A good physical therapist will ensure that exercises for patients with diabetic neuropathy do not hurt their feet, which are usually sensitive.
Other therapies include devices that can be used to keep painful extremities from touching the bed or chair. Topical lotions and some supplements may also provide relief.
A chiropractor, massage therapist, or osteopath can carry out regular massages or manual therapy to stretch the muscles. Massage can inhibit muscle contractures, spasms, and atrophy due to poor blood supply. Specific exercises, such as swimming or aerobics can develop and maintain muscle strength and reduce muscle mass reduction.
Therapeutic ultrasound uses very high-frequency sound waves to stimulate the tissue beneath the skin's surface. This can help some patients to regain sensitivity in their feet.
A number of complications are linked to diabetic neuropathy, and patients should be aware of the risks of developing these.
Possible complications include:
- A lack of sensation in the feet and a resulting risk of not feeling cuts or sores, which can become infected, leading to a risk of amputation
- Bladder and kidney infections
- Muscle damage or loss of muscle mass
- Frequent nausea and vomiting will reduce blood sugar control.
To prevent the complications of diabetic peripheral neuropathy, good foot care is needed. People with the condition should inspect their feet every day for injuries or sores. Smoking increases the risk of foot problems. A podiatrist can help with foot care, and a health care provider can give advice on quitting smoking.