US Pharm. 2021;47(3):15.

Nerve Damage Due to Diabetes

Our bodies contain entire networks of nerves responsible for sending information from the brain to the rest of the body and back. The part of this network located within the brain and spinal cord is called the central nervous system. The remainder of the nerves and ganglia located outside of our brain and spinal cord are, collectively, the peripheral nervous system. Peripheral neuropathy is a term used to describe damage to nerves in the peripheral nervous system. It is common in those with diabetes. Although it is not entirely clear why diabetes causes nerve damage, it is thought to be a result of poorly controlled blood sugar over a long period of time.

Types of Nerve Damage

There are three general types of nerves that can be damaged in peripheral neuropathies—the sensory, autonomic, and motor nerves. Diabetic peripheral neuropathy (DPN) that affects the sensory nerves results in symptoms such as numbness, tingling, increased sensitivity to touch, and burning in the feet, legs, hands, and arms. When autonomic nerves are damaged, symptoms include problems with digestion, breathing, vision, heartbeat, sexual function, and bladder control. Motor nerve damage can be seen in patients with muscle weakness, cramping, or twitching.

High blood sugar can lead to damage of the sensory, autonomic, and motor nerves that play an important role in health. The risk of nerve damage increases with time, so most of the health consequences of long-term diabetes occur many years after diagnosis. Eventually, more than half of all  diabetics will have some degree of peripheral neuropathy, although not everyone will suffer from its symptoms. It is likely that high blood sugar, high cholesterol, hypertension, and obesity contribute to the damage of peripheral nerves.

Diagnosis of DPN is based on a thorough review of symptoms, as well as a physical examination and testing to determine the type of nerve damage and its severity.

Regular Foot Care Is Essential to Prevent Infection

A serious complication of DPN is infection. Regular foot care is very important in prevention and early treatment of infection, which may be missed due to lack of symptoms and poor peripheral circulation with advancing age. When a soft-tissue infection spreads to the bone, amputation of the toes or foot may be required. Prompt recognition of an infection and timely treatment can prevent many of these surgeries.

Patients with diabetes should have a foot examination at least once a year to check for neuropathy. If a sensory neuropathy is detected, more frequent foot examinations should be scheduled to assist in early detection of infections, as well as their prompt treatment.

Treatment and Prevention Options

The best treatment for DPN is prevention, and tightly controlling glucose levels is the key to success. It is important to maintain a healthy diet, exercise regularly, and limit alcohol. Proper foot care is essential to avoid infections. Nicotine constricts blood flow to peripheral nerves, so smoking cessation is very important to prevent the progression of diabetic nerve damage. Specific treatments are available for individual types of neuropathies, including oral and topical medications.

Treatment of DPN depends on the type and severity of nerve damage. Strict blood sugar control is the most important step toward limiting the progression of nerve damage and preventing future complications. Once blood sugar is in a normal range and diet, exercise (or physical therapy), and medications are adjusted to maintain good control over blood-sugar fluctuations, treatment to help relieve symptoms can begin.

Diabetic nerve pain is treated with antidepressant medications, antiseizure drugs, and OTC and prescription medications for pain. Drugs specifically approved to treat the pain of DPN include duloxetine (Cymbalta), pregabalin (Lyrica), and tapentadol (Nucynta). Skin creams and transdermal patches are also available. Medications are also used to improve stomach emptying, blood pressure, bladder control, and sexual function associated with DPN.

The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.

To comment on this article, contact rdavidson@uspharmacist.com.