Diabetic Foot Pain
Diabetes Affects the Nerves of the Foot
Involvement of nerves is probably the most common complication of diabetes, and 50% of diabetics will experience nerve damage (polyneuropathy) eventually. The approach to diabetes, what is called “pre-diabetes,” can cause the loss of the small nerve fibers in the feet that sense pain, touch, and temperature. By the time diabetes is diagnosed, 10-18% of patients already have nerve damage in their feet. It is most often symmetrical, in both feet, but with continued sensory loss, the nerve problems and the complications that arise from them are prone to rise higher to involve the legs.
Who Is at Risk for Diabetic Foot Pain?
Nerve damage due to diabetes is related to vascular damage. Every tissue in the body requires oxygenation and this requires an adequate blood supply. The vascular disease from diabetes injures the nerves by affecting the blood supply to them. Therefore, those diabetics with additional cardiovascular disease are at higher risk for diabetic foot pain, specifically:
- Those with high triglycerides
- Obese patients
- Older patients
- Those with hypertension
A Global Perspective
All of these risk factors should be addressed by the doctors who manage the diabetes, but since all of these put patients further at risk for the vascular disease that can complicate their diabetes, the greatest overriding risk–and the first and foremost risk to address–is the poor sugar control that partners negatively with the vascular disease. Seeing all of these contributions together is the proper way to evaluate and address diabetic foot pain.
Can Diabetic Foot Problems Be Diagnosed?
Just as in diagnosing any illness, diagnosing diabetic foot pain is accomplished by a healthcare professional observing for signs and symptoms of the foot problems associated with diabetes and testing for abnormalities in the sense of touch and the perception of vibration.
Signs and Symptoms of Diabetic Foot Pain
The signs and symptoms of nerve damage to the feet due to diabetes include:
- Loss of the ability to sense vibrations
- Loss of coordination
- Loss of the sense of pain, light touch, and temperature
- Later in the disease process, foot pain
Complications of Diabetic Nerve Damage in the Feet
Because of the vascular compromise to the nerves providing sensory input for the tissues of the feet in diabetics–and the resulting failure of those nerves to provide pain as a warning signal–the damage due to nerve deficiencies is insidious. Therefore, complications from this damage can sneak up on an unsuspecting patient.
When the nerves cannot warn a patient of harm or injury, the very loss of these sensations puts the patient at risk for even more damage since it continues unnoticed for some time. Eventually, the patient experiences the unmistakable problems of diabetic ulcers, infections, and inflammation not only can involving the feet, but affecting their deeper tissues and even joints.
Today, this relentless cascade of complications can even reach the point of requiring amputation, and today diabetes is one of the leading causes of amputations. This end-result is as unnecessary as it is serious, as it is completely preventable, and prevention is traditionally the safest, cheapest, and smartest way to maintain health.
Management of Diabetic Foot Problems
Management of any complication of an illness must initially involve the management of the illness itself. This prevents progressive damage while affording the opportunity to address the complications. In diabetes, this requires reigning in the hyperglycemia that is toxic to blood vessels.
Management of the diabetic illness itself is the crucial linchpin in management of complications from diabetes, such as diabetic foot pain. A simple blood test, the hemoglobin A1c, is done every three months as an important tool for doctors to follow their patients and ensure good diabetic control. Once the diabetes is under control, the healthcare professional is best equipped to treat its complications.
Secondarily, but important also, is evaluating for and managing other risk factors such as hypertension, triglyceride control, smoking, etc.
Treatment of Diabetic Foot Pain
Because of the sensory deficiencies in the nerves, not all diabetics develop foot pain. However, if it occurs, its management is via three approaches:
- Glycemic control: This means that since diabetic foot pain or neuropathy is caused by poor control of diabetes (higher sugar in the blood than what is optimal), then controlling sugars better will help lessen the problem and—more importantly—prevent further damage.
- Foot care: The feet should be inspected daily for any dry or cracking skin, splits, or infections. Foot care also includes frequent re-checks by one’s doctor who can pick up on warning signals or follow any problems over time.
- Pain management: Only a few people with diabetes have severe, debilitating pain, but of those who do, pain can be approached via a step-wise protocol of antidepressants, anticonvulsants, anti-inflammatories, and topical anesthetics, and if necessary, a combination that may or may not include opioids. The best management of the pain, however, is to prevent it from ever occurring by way of frequent doctor visits.
Prevention of Diabetic Foot Pain
The best strategy for prevention is frequent and routine foot evaluations for possible diabetic nerve disease (neuropathy). There are several screening tests that can be used, typically consisting of a history, a tuning-fork test for the ability to sense vibrations, and a check of skin integrity, sensitivity, and reflexes.
In diabetic care of the feet, there should be routine inspection of the toenails for evidence of fungal infection, and the feet should be examined for changes due to improper footwear, such as calluses and discoloration.
An annual comprehensive exam includes:
- A check of the skin for integrity, redness, calluses, and fissures, especially between the toes and at the pressure points involved in simple walking. Bony and joint deformities, as well as mobility, balance, and gait are part of a comprehensive exam
- Assessment of vascular disease by noting any history of circulation problems and by determining the quality of the pulses in the feet
- A test for loss of sensation using a thin filament to map areas that are suspicious for insensitivity. Additionally, tuning fork testing, pinprick sensitivity, and reflexes are checked
- Quitting smoking if a smoker
- Avoiding going barefoot, even at home
- Determining the water temperature before stepping into a bathtub
- How to trim toenails properly, i.e., to the shape of the toe, filing sharp edges, and avoiding cutting the cuticles
- Washing and checking one’s feet daily
- Advice on shoes, i.e., snug but not tight and, if necessary, customized for any ulcerations or deformities (calluses, bunions, etc.)
- Wearing socks at all times