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FOOT COMPLICATIONS - DIABETES

What are they ?

Everyone’s feet are prone to minor injury. People with diabetes are particularly liable to develop complications of such injury. To begin with, you may be quite unaware that you have damaged your foot or toes. This is because of the reduced sensation of pain and pressure, which results from diabetic nerve damage. This is called neuropathy. A cut during toenail care, or a blister from ill-fitting shoes can become infected quite easily. This can result in an ulcer, which may be very slow to heal. In some people, neuropathy results in muscle weakness within the foot. The arches then drop and the toes become deformed. This produces unnatural pressure points on the sole and toes and leads to excessive hard skin or callus, under which ulcers are more likely to develop.

Poor blood circulation (called peripheral vascular disease) is present in many people with long-standing diabetes. This often plays a part in causing foot infection and its consequences. If an ulcer or other infection becomes chronic, the underlying bone may become infected as well. This condition, called osteomyelitis sometimes makes the infection difficult to treat, even with modern, powerful antibiotics. The bone may even fracture at the site of infection. Osteomyelitis may be resistant to treatment. There is also a risk of infection spreading through the bloodstream to other organs. Amputation of part of the leg may then have to be considered. Loss of nerve sensation in the joints occasionally leads to a particular type of swelling of the feet, with distortion and destruction of the foot bones. This is called Charcot’s neuro-arthropathy.

How do they occur ?

If hard skin on the ball of the foot becomes excessive, the underlying tissue may break down and form fluid, which leads to ulcers. In other cases, it is some minor carelessness or accident which causes the injury. Self care of the toenails particularly risks injury, if your eyesight is impaired by retinal damage (retinopathy) or by cataract. Similarly, applying corn plasters or other damaging medication to the skin can cause a problem. Even barefoot walking is a hazard. New shoes may be a cause: you may not appreciate that they are too small for you because of nerve damage. Remember, it is unusual for a foot infection to develop without some physical damage to the foot, caused either by you or your circumstances

Why do they occur ?

After many years, some degree of nerve damage occurs in most people with diabetes. It is likely to occur earlier and more severely if blood glucose control is not ideal. Neuropathy reduces the ability to feel minor injury. and hard skin under the foot. Hardening and narrowing of the arteries is also common in longstanding diabetes, particularly in older age and in smokers. The resulting poor circulation to the feet results in poor oxygen delivery to your tissues. This in turn hinders both the response to infection as well as healing of wounds. Poor control of your blood glucose levels also interferes with the body’s defence against infection as well as the process of wound healing.

Treatment Involved

PREVENTION is the most important element of care. This is achieved firstly by examining your feet carefully every day for minor injury or blister. Washing and carefully drying your feet every day is also important. Dry, cracked skin, especially on the heels are a possible point of entry for germs: keep these areas soft with E45 cream or similar preparations, Build up of hard skin on the sole of the foot should be removed by a qualified podiatrist (chiropodist). You must also find out whether your nerves and blood circulation have been affected by diabetes. So, ask your doctor at the annual examination whether his or her tests show you to have circulatory or neuropathy problems, which might put your feet "at risk". You should also find out if your eyesight is good enough to cut your own toenails safely. It is important to avoid cutting nails too short, especially at the sides. It may be better and safer to file them, or have your foot care undertaken only by a qualified podiatrist (chiropodist). Avoid all proprietary corn cures and let your doctor, diabetes nurse or podiatrist know as soon as you notice anything unusual in your feet, including a change in the colour of the skin: this may indicate circulation problems. Avoid barefoot walking, even in your own home - it is surprising what can lurk even in a carpet. Get expert help when buying new shoes, to be sure that you are not buying ones which are too small for you.

Make sure that you keep your diabetes as well controlled as possible all the time, by regularly checking your own glucose tests. Your doctor will also assess the long term control by a blood test (usually called HbA1c). This tells him (and you) what your control has been over the preceding 10 weeks or so. An HbA1c level below 7% is likely to reduce your risk of nerve damage and may ensure better healing of wounds and infections. Above all, do not smoke! This a major cause of artery damage. TREATMENT. Once an infection occurs, assessment and treatment are urgent. Do not wait for the next routine appointment, in the hope that healing will occur on its own. A swab will be taken of any infected area, and perhaps an x-ray too, to see whether the underlying bone has been affected. If circulation problems are thought to be playing a part in your problem, you may have a blood vessel x-ray called an angiogram. This will confirm if there is any narrowing or blockage of a key artery. If so, angioplasty (balloon stretching of the artery) or bypass surgery may be considered. Antibiotics are often prescribed, and you must take the full course, even if you believe that the infection has healed. Simple dry dressings may be used on infected areas, although some medicated dressings and other preparations may be used to speed up healing in chronic ulcers. You may be advised to have the dressings carried out by a nurse, rather than doing them yourself. You will be advised to avoid pressure on an infected area. This may require wearing a temporary protective boot or plaster cast, If the infected area is large. Enclosing the foot in a plaster cast is also used in some cases of Charcot’s neuroarthropathy. There is also some evidence to support the use of drugs called bisphosphonates in the treatment of this disorder. These drugs can be given by mouth, or more effectively by an intravenous drip. In some people, there is a place for customised shoes to avoid pressure points and provide arch support.

During Treatment

It is important to complete any course of antibiotics, even though this may take several weeks. Rest and the avoidance of pressure on ulcers are both important, and it may be necessary to take time away from your normal duties to ensure that full healing occurs. Do try and get your diabetes under the best possible control. Keeping your blood glucose levels below 10mmol/litre (180mg/100ml) is an important goal. If you are on tablet treatment, you may need to change temporarily to insulin: if already on insulin, a bigger dose or a different regimen may be needed.

After Treatment

Do make sure that you follow immaculate foot care. To be on the safe side, have all your foot care done by your podiatrist (chiropodist). Ulcers are liable to break down again. If you have had one infection, you now know that your risk of having a further one is quite high. Try and keep your diabetic control as good as possible, even once healing has occurred. This may help to reduce the risk of further problems.

If Left Untreated

You would be at risk of spreading infection. This could cause blood poisoning as well as involving other organs. You would also increase the likelihood of needing amputation of a toe or part of the leg.

Effects on Family

They must understand that you may not be able to carry out your normal responsibilities for some time. People often rally around to help in these situations: do not be afraid to ask.