Diabetic neuropathy describes the nerve damage that is caused by the persistently raised blood sugar found in diabetic individuals. The risk of developing diabetic neuropathy increases the longer a person has diabetes and neuropathy affects up to 50% of individuals with the condition.

In some diabetics, the onset of neuropathy does not cause any symptoms. Some, however, may develop pain, tingling, or numbing across the extremities such as the fingers, hands, arms, legs and feet. These symptoms may be mild at first and not cause concern until the condition has progressed to a more advanced stage. However, with some types of neuropathy the onset of pain may be sudden and severe. Nerve damage may also affect other organs such as the heart, digestive tract and sex organs.

Causes

The persistently high levels of glucose in the blood seen in diabetes eventually leads to a narrowing of the small blood vessels that supply nerve endings with vital nutrients and oxygen. Without this supply of nutrients and oxygen, nerve fibres become damaged or even disappear.

Types of diabetic neuropathy

Peripheral diabetic neuropathy is the most common type of diabetic neuropathy and causes pain and numbness in peripheries such as the toes, feet and hands.

Autonomic neuropathy affects systems that are regulated by the autonomic nervous system, causing changes in bowel movement, bladder control, sexual function and blood pressure, for example.

Proximal neuropathy causes pain in the thighs, hips or buttocks and leads to leg weakness.

Focal neuropathy or mononeuropathy describes damage to a specific nerve. This type of neuropathy often comes on suddenly and usually causes pain in the face, leg or torso.

Diagnosis and treatment

An examination of symptoms and certain tests may help to diagnose diabetic neuropathy. One main check that is performed is examination of the feet to check for sores and ulcers that a person may not necessarily be aware of if their feet have become numb through nerve damage. Other tests include the monofilament test, nerve conduction tests and electromyography.

Treatment involves keeping blood sugar levels under strict control, with regular monitoring of blood glucose, adherence to an antidiabetic diet, physical activity and blood pressure checks.

Medications used to treat diabetic neuropathy include tricyclic antidepressants such as amitriptyline, imipramine, and desipramine, and antiseizure medications such as pregabalin, gabapentin, carbamazepine and lamotrigine. For painful neuropathy, pain relieving opioids such as oxycodone and tramadol may be used.