Foot problems are common in people with diabetes. They can happen because high blood sugar damages the nerves in your feet and reduces circulation. It can also cause ulcers (open sores) to form.
Foot infections and osteomyelitis require prompt diagnosis and treatment. Debridement, systemic antibiotics and “off-loading” (using special shoes or a brace or specialized casting to relieve pressure on the ulcerated area) are important.
Diabetic Neuropathy
Nerve damage caused by diabetes is called diabetic neuropathy (neur-OH-pathy). It can affect your feet, hands and legs. The condition is more likely to happen the longer you have diabetes and the higher your blood sugar levels are. It can also be caused by other things, like pinched nerves, nutrient deficiencies or vascular problems.
Diabetic neuropathy can lead to foot complications, like sores, ulcers and infections. The loss of sensation in the feet means that a cut or blister on your foot may go unnoticed, or you might not feel heat or cold. Infections can spread to the bones, causing osteomyelitis (in-muh-so-LEE-tis), and sometimes to the point where the foot must be amputated.
Keeping your blood glucose on target and regular foot exams help to prevent neuropathy. Your doctor will examine your feet with different tools and ask about your symptoms. They will check your sensitivity to touch and temperature, using nylon thread or a tuning fork, and do a nerve conduction study or electromyography — tests that measure the flow of electricity through your nerves or the movement of your muscles.
Other tests can show whether your autonomic nerves, which control involuntary functions like sweating, are working well. Medicines, such as the serotonin and norepinephrine reuptake inhibitor duloxetine (Cymbalta) or extended-release antidepressants desvenlafaxine (Effexor XR) and venlafaxine (Pristiq), might improve pain from peripheral neuropathy.
Poor Circulation
Poor circulation is another diabetes complication that can put you at risk for foot problems. It can reduce the amount of oxygen and nutrients that reach your feet, so wounds don’t heal well. You also might develop a condition called peripheral arterial disease, which narrows and hardens blood vessels in your legs and feet. This can lead to critical limb ischemia (CLI), which can have serious health consequences including amputation.
People with diabetes are also more likely to have nerve damage, which can make your feet less sensitive. This can make it hard to feel pain or temperature changes in your feet. It can also mean that you don’t notice minor cuts, blisters or sores on your feet. That can lead to infection and foot ulcers that won’t heal.
If you have diabetes, it is important to check your feet every day for swelling, redness and heat — these can be signs of infection. You should also wash your feet daily and dry them completely, especially between your toes. You can use a pumice stone or a plain petroleum jelly to keep calluses from building up. But don’t soak your feet or put cream on them.
It is also important to test your blood flow with foot pulse palpation. Your doctor can help you find the best way to do this.
Ulcers
Ulcers are open wounds that can take almost any shape. They are a serious problem that can cause infection and lead to the need for part of a foot or toe to be surgically removed (amputated). Foot ulcers occur in about 15% of people with diabetes.
They can be caused by a combination of factors such as lack of sensation (neuropathy), poor circulation, foot deformities, irritation or friction (such as rubbing from shoes) and high pressure on the wound bed from calluses or hammertoes. Ulcers can be hard to heal because of the damage done by diabetes to blood vessels and nerves.
If the ulcer gets infected, your doctor will clean and disinfect the area and prescribe antibiotics.
You can help your ulcer heal by not wearing tight shoes, and by putting a padded shoe insert or sock in your shoe to reduce the amount of pressure on the ulcer. You may need to use a walker or crutches while the ulcer heals, and you might have to wear a cast or brace that takes pressure off the affected foot or toe. You can also put a special dressing on the ulcer that helps it heal faster. It’s called a moist-to-dry dressing and it has ingredients that dissolve dead skin cells and keep the area clean.
Prevention
People with diabetes can avoid serious foot problems by keeping their blood sugar levels close to target and following a foot care routine. Getting regular care at home and going to all doctor’s appointments will help prevent serious problems from developing, such as damaged nerves or poor circulation.
Nerve damage (neuropathy) can affect the feet and legs, causing numbness or loss of feeling in these areas. This makes it difficult to know when you have a cut, blister or sore on your foot. If you lose the ability to feel pain, a minor problem might not be noticed and might become infected. If the infection spreads, it may lead to a foot ulcer that does not heal.
Fortunately, most foot ulcers can be prevented by wearing proper footwear that offloads high-stress areas of the feet. Unfortunately, there is a gap between evidence-based recommendations and practice.
Early detection and prompt treatment of infected diabetic foot wounds are critical to avoiding the disastrous progression to septic gangrene that may require lower-limb amputation. Proper surgical debridement, drainage and wound lavage are essential. Obtaining specimens from infected wounds for culture and antibiotic susceptibility testing helps guide appropriate therapy. In addition, identifying and counselling individuals at risk of foot complications can help prevent ulceration and infection.