Diabetic Peripheral Neuropathies

Doctor testing sensibility of foot
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Diabetes is one of the most common medical disorders in the United States. Briefly, diabetes leads to blood sugar levels being abnormally high, which can lead to a wide range of complications. In addition to increasing the risk of diseases like stroke and heart attack, diabetes can lead to kidney disease, eye problems, and disorders of the peripheral nervous system.

Diabetic Peripheral Neuropathy

Peripheral neuropathy is also very common, especially in older people, and is not uncommonly one of the first signs of diabetes.

For this reason, anyone with a newly discovered peripheral neuropathy should be tested for diabetes with a blood sugar level or a hemoglobin A1c (which assesses long-term glucose levels in the blood).

Diabetic neuropathy may just cause a subtle numbness, but other times is quite painful. The disorder impacts the longest nerves in the body first, meaning those that go from the spine to the feet. As a result, people may have numbness or a burning pain in the toes, which spreads slowly up the legs as the disease worsens. This can become very serious as people may not notice when their foot has a serious injury, which can lead to ulcers or infections. It’s a good idea for people with diabetes to visually inspect their feet routinely. This can involve avoiding activities that might injure feet, being careful when trimming nails, and washing the feet daily.

There’s no cure for diabetic peripheral neuropathy, though better control of blood glucose and pain control can improve symptoms.

Medications such as gabapentin or tricyclic antidepressants may be beneficial for reducing burning neuropathic pain.

Diabetic Autonomic Neuropathy

In addition to sensation changes, diabetes can impact the autonomic nervous system, which normally helps control blood pressure, heart rate, digestion and more.

As a result, people with diabetes can have orthostatic hypotension, constipation, bladder dysfunction, sweating abnormalities, and sexual dysfunction.

Orthostatic hypotension results from diminished ability to keep blood in the brain when standing up. Normally the blood vessels of the body contract and the heart rate increases slightly on standing, but if the peripheral nerves that normally signal for these changes are damaged, such adjustments may not occur, resulting in blood pooling in the legs instead of moving towards the head. Without blood bringing oxygen to the brain, the brain temporarily shuts down, leading to lightheadedness and passing out.

Loss of autonomic nerves to the digestive system can lead to slowing of food through the digestive tract. This may lead to people feeling full earlier than they previously would, and also can result in diarrhea or constipation. A change of dietary habits and sometimes specific medications may be helpful in treating this gastroparesis.

Diabetic Amyotrophy

Diabetes can also lead to weakness by damaging the lumbosacral nerves. Proximal neuropathy in diabetes mellitus involves severe aching and burning in the hip and the thigh, followed by weakness and wasting of thigh muscles.

This often occurs more in one leg than the other. The onset is usually after middle age, and it may go along with other forms of neuropathy, such as the distal, sensory neuropathy common in diabetes—those with such a neuropathy are more likely to have a more gradual onset impacting both legs.

The exact cause of this diabetic lumbosacral plexopathy is not known. Some suggest that it’s an immune-mediated vasculopathy, meaning a disease of the small blood vessels in the muscle. Immune modulating agents have been suggested to help, though the main mean of treatment is control of diabetes, though these are based off small retrospective studies.

A well-controlled study suggested that pulse methylprednisolone was not beneficial compared to placebo. Pain may be controlled with tricyclic antidepressants or antiepileptics such as gabapentin. Physical and occupational therapy is also useful.

The overall prevalence among people with diabetes is less than 1 percent. It is more common in type 2 than type 1 diabetes. It is most common in ages greater than 50. Proximal muscle wasting and weakness, including difficulty getting up from chairs or climbing stairs, is more difficult. In about 21 percent of cases, diabetic amyotrophy is the first sign of diabetes.

About 60% of patients recover somewhat within 12-24 months, though relapses can occur, and some mild weakness and discomfort can last for years. The diabetic lumbosacral plexopathy occurs with significant recent weight loss and poor glycemic control.

Other things to consider include hematoma, ischemic lumbar plexopathy, or lumbar radiculopathy. To ensure these things are not present, medical work-up may include an MRI of the lumbar plexus, mostly to rule out structural lesions rather than definitively visualize the associated pathology of the disease itself. Electromyography (EMG) may also be useful.


Ropper AH, Samuels MA. Chapter 41. Diseases of the Nervous System Caused by Nutritional Deficiency. In: Ropper AH, Samuels MA, eds. Adams and Victor's Principles of Neurology. 9th ed. New York: McGraw-Hill; 2009.

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