Nerve Disorders

Diabetic Peripheral Neuropathy

What Is Diabetic Peripheral Neuropathy?

Diabetic neuropathy is nerve damage caused by diabetes. When it affects the arms, hands, legs and feet, it is known as diabetic peripheral neuropathy. Diabetic peripheral neuropathy is different from peripheral arterial disease (poor circulation), which affects the blood vessels rather than the nerves.

Three different groups of nerves can be affected by diabetic neuropathy:

  • Sensory nerves, which enable people to feel pain, temperature and other sensations
  • Motor nerves, which control the muscles and give them their strength and tone
  • Autonomic nerves, which allow the body to perform certain involuntary functions, such as sweating

Diabetic peripheral neuropathy does not emerge overnight. Instead, it usually develops slowly and worsens over time. Some patients have this condition long before they are diagnosed with diabetes. Having diabetes for several years may increase the likelihood of having diabetic neuropathy. The loss of sensation and other problems associated with nerve damage make a patient prone to developing skin ulcers (open sores) that can become infected and may not heal. This serious complication of diabetes can lead to loss of a foot, a leg or even a life.

Causes

The nerve damage that characterizes diabetic peripheral neuropathy is more common in patients with poorly managed diabetes. However, even patients living with diabetes who have excellent blood sugar (glucose) control can develop diabetic neuropathy. There are several theories as to why this occurs, including the possibilities that high blood glucose or constricted blood vessels produce damage to the nerves.

As diabetic peripheral neuropathy progresses, various nerves are affected. These damaged nerves can cause problems that encourage development of ulcers. For example:

  • Deformities (such as bunions or hammertoes) resulting from motor neuropathy may cause shoes to rub against toes, creating a sore. The numbness caused by sensory neuropathy can make the patient unaware that this is happening.
  • Because of numbness, a patient may not realize that s/he has stepped on a small object and cut the skin.
  • Cracked skin caused by autonomic neuropathy, combined with sensory neuropathy’s numbness and problems associated with motor neuropathy, can lead to developing a sore.

Motor Neuropathy (Deformity) + Ill-Fitting Shoes + Sensory Neuropathy (numbness) = Ulcers (sores)

Symptoms

Depending on the type(s) of nerves involved, one or more symptoms may be present in diabetic peripheral neuropathy.

For sensory neuropathy:

  • Numbness or tingling in the feet
  • Pain or discomfort in the feet or legs, including prickly, sharp pain or burning feet

For motor neuropathy:

  • Muscle weakness and loss of muscle tone in the feet and lower legs
  • Loss of balance
  • Changes in foot shape that can lead to areas of increased pressure

For autonomic neuropathy:

  • Dry feet
  • Cracked skin

Diagnosis

To diagnose diabetic peripheral neuropathy, the foot and ankle surgeon will obtain the patient’s history of symptoms and will perform simple in-office tests on the feet and legs. This evaluation may include assessment of the patient’s reflexes, ability to feel light touch and ability to feel vibration. In some cases, additional neurologic tests may be ordered.

Treatment

First and foremost, treatment of diabetic peripheral neuropathy centers on control of the patient’s blood sugar level. In addition, various options are used to treat the painful symptoms.

Medications are available to help relieve specific symptoms, such as tingling or burning. Sometimes a combination of different medications is used.

In some cases, the patient may also undergo physical therapy to help reduce balance problems or other symptoms.

Prevention

The patient plays a vital role in minimizing the risk of developing diabetic peripheral neuropathy and in preventing its possible consequences. Some important preventive measures include:

  • Keep blood sugar levels under control.
  • Wear well-fitting shoes to avoid getting sores.
  • Inspect your feet every day. If you notice any cuts, redness, blisters or swelling, see your foot and ankle surgeon right away. This can prevent problems from becoming worse.
  • Visit your foot and ankle surgeon on a regular basis for an examination to help prevent the foot complications of diabetes.
  • Have periodic visits with your primary care physician or endocrinologist. The foot and ankle surgeon works together with these and other providers to prevent and treat complications from diabetes.

Morton’s Neuroma (Intermetatarsal Neuroma)

What Is a Neuroma?

A neuroma is a thickening of nerve tissue that may develop in various parts of the body. The most common neuroma in the foot is a Morton’s neuroma, which occurs between the third and fourth toes. It is sometimes referred to as an intermetatarsal neuroma. “Intermetatarsal” describes its location in the ball of the foot between the metatarsal bones. Neuromas may also occur in other locations in the foot.

The thickening, or enlargement, of the nerve that defines a neuroma is the result of compression and irritation of the nerve. This compression creates enlargement of the nerve, eventually leading to permanent nerve damage.

Causes

Anything that causes compression or irritation of the nerve can lead to the development of a neuroma. One of the most common offenders is wearing shoes that have a tapered toe box, or high-heeled shoes that cause the toes to be forced into the toe box.

People with certain foot deformities – bunions, hammertoes, flatfeet, or more flexible feet – are at higher risk for developing a neuroma. Other potential causes are activities that involve repetitive irritation to the ball of the foot, such as running or court sports. An injury or other type of trauma to the area may also lead to a neuroma.

Symptoms

If you have a Morton’s neuroma, you may have one or more of these symptoms where the nerve damage is occurring:

  • Tingling, burning, or numbness
  • Pain
  • A feeling that something is inside the ball of the foot
  • A feeling that there’s something in the shoe or a sock is bunched up

The progression of a Morton’s neuroma often follows this pattern:

  • The symptoms begin gradually. At first they occur only occasionally, when wearing narrow-toed shoes or performing certain aggravating activities.
  • The symptoms may go away temporarily by removing the shoe, massaging the foot, or by avoiding aggravating shoes or activities.
  • Over time the symptoms progressively worsen and may persist for several days or weeks.
  • The symptoms become more intense as the neuroma enlarges and the temporary changes in the nerve become permanent.

Diagnosis

To arrive at a diagnosis, the foot and ankle surgeon will obtain a thorough history of your symptoms and examine your foot. During the physical examination, the doctor attempts to reproduce your symptoms by manipulating your foot. Other tests or imaging studies may be performed.

The best time to see your foot and ankle surgeon is early in the development of symptoms. Early diagnosis of a Morton’s neuroma greatly lessens the need for more invasive treatments and may avoid surgery.

Non-surgical Treatment

In developing a treatment plan, your foot and ankle surgeon will first determine how long you’ve had the neuroma and evaluate its stage of development. Treatment approaches vary according to the severity of the problem.

For mild to moderate neuromas, treatment options may include:

  • Padding. Padding techniques provide support for the metatarsal arch, thereby lessening the pressure on the nerve and decreasing the compression when walking.
  • Icing. Placing an icepack on the affected area helps reduce swelling.
  • Orthotic devices. Custom orthotic devices provided by your foot and ankle surgeon provide the support needed to reduce pressure and compression on the nerve.
  • Activity modifications. Activities that put repetitive pressure on the neuroma should be avoided until the condition improves.
  • Shoe modifications. Wear shoes with a wide toe box and avoid narrow-toed shoes or shoes with high heels.
  • Medications. Oral nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, may be recommended to reduce pain and inflammation.
  • Injection therapy. Treatment may include injections of cortisone, local anesthetics or other agents.

When Is Surgery Needed?

Surgery may be considered in patients who have not responded adequately to non-surgical treatments. Your foot and ankle surgeon will determine the approach that is best for your condition. The length of the recovery period will vary, depending on the procedure performed.

Regardless of whether you’ve undergone surgical or nonsurgical treatment, your surgeon will recommend long-term measures to help keep your symptoms from returning. These include appropriate footwear and modification of activities to reduce the repetitive pressure on the foot.