Dr. S.M.Sadikot.
Hon. Endocrinologist,
Jaslok Hospital and Research Centre,
Mumbai 400026

In Greek mythology, there was once a great warrior called Achilles. When he was a small baby, the Gods told his mother to dip him in river Styx as this would make him completely safe from any harm or injury. The mother held him up by his heels and dipped him completely in the river. As Achilles grew up he became renowned as a fearless warrior and the fable grew that nobody could ever defeat him as nothing could ever injure him! Until one day, another famous warrior called Paris shot a poisoned arrow which hit Achilles in his heel. This was the part of the body that had been held in the mother's hand when she had dipped him in the river and therefore was not safe from harm. The poisoned arrow did kill Achilles. From that day onwards, any vulnerable aspect of a person, has been called as the "Achilles heel" of that person.

In my opinion, this could well be applied to the feet of any diabetic. We tend to pay so much attention to the long term complications of diabetes like eye, kidney and nerve problems that we overlook the importance of foot care in diabetes. In view of the morbidity, if not mortality, associated with foot problems, this attitude is quite unfortunate, as we shall soon see.

The importance of foot problems in a diabetic should NEVER be underestimated. It should be remembered that second highest cause of foot amputations in our country and this true of many developing countries also are diabetes induced foot problems. Moreover, if one were to see the number of indoor patients in any specialised diabetic clinic or hospital, one would find more than half are there because of some foot problem. These are also patients who need to stay in the hospital the longest and whilst with excellent management, we are able to save many feet, a significant number of these patients still require surgical intervention. The medical and socioeconomic cost to these patients and their families is mind boggling.

This is all the more unfortunate as the vast majority of foot problems occur in those with with insensitive feet, possibly without adequate circulation and are PRECIPITATED by infection, injury, or both. Due to the fact that there are usually definite precipitating factors, a vast number of the foot problems are preventable! Even if they do occur, it is possible to "catch" them at the earliest so that the management is simpler and the morbidity minimal, if any.

The tragedy is that many of us do not pay adequate attention to the feet of our patients. How often do we instruct patients to examine feet daily and even take the trouble to show them how this should be done? For that matter, how often do we insist that the feet of the patient be examined every time they comes to us? In fact, it has been said, possibly in a lighter vein, that the most important step in the prevention of foot problems is for the doctor to ask the patient to take off the shoes.

I would like to quote a passage from the ancient chronicles. "In the thirty ninth year of his reign Asa was diseased in his feet, and his disease became severe; he sought help from his physicians but died in the forty first year of his reign." (II Chronicles XVI, 12-14). Some authorities regard this quotation as one of the earliest reference to diabetic foot disease and many of the more sceptical ones feel that there is not much more that we can do today about diabetic foot problems as compared to what was done for Asa. This attitude is unfortunate as foot problems in diabetes are preventable provided a few basic instructions are followed and proper care taken. Unfortunately even in specialised institutions which may pay attention to foot problems, the patient either gets some rapid oral instructions about foot care or may even be given a small slip of paper detailing briefly the instructions. Whilst, this may be better than doing nothing, it still does not solve the problem, because more often than not, the oral instructions are forgotten by the time the patient reaches home and the small piece of paper is either filed or lost. Even if the patient were to remember his instructions to inspect the feet, does this really mean much to the patient? What is the patient supposed to look for? How is he supposed to look for any problem and how often? How can he care for his feet? What is he supposed to do in case of any problem (and possibly, more important, what is he NOT supposed to do)?

Before we discuss the "do's and don'ts" about foot care, it would be worthwhile to consider briefly some of the mechanisms which predispose the patient to foot problems. This would allow us to instruct the patient in a much more rational manner rather than just giving him some "commandments" to observe.

We all know that diabetic neuropathy is the commonest longterm complication associated with diabetes and I have discussed this separately in another chapter. Here, I will only discuss those aspects that have direct bearing on the foot problem.

Involvement of the sensory nerves going to the feet brings about many varied symptoms and signs but many patients have a marked reduction in the pain sensations and a significant number of the patients go on to have insensitive feet, and are incapable of feeling any type of sensation. The patient may not feel any pain or other uncomfortable sensations. Therefore, often they may not be aware of any the presence of any injury or infection until these may have progressed to a severe stage, or they are pointed out by a relative or the doctor. Thus it may not be possible to detect the presence of any injury or infection at a stage when management may be a lot easier.

Although diabetic neuropathy more commonly affects the sensory nerves, the motor nerves may also be involved. The motor nerves which innervate the small muscles of the feet help in maintaining the shape and the "arches" of the foot. When these nerves are affected, there is a wasting of the small muscles of the feet and this may change the configuration of the foot. The toes may become "cocked" up and the area of the sole near the heads of the metatarsals comes to bear most of the weight of the body. This is made worse by changes taking place in the small joints of the foot due to diabetic nerve and bone damage. The change in the normal architecture of the foot accompanied by a decrease in the sensitivity is one of the most important predisposing factor in diabetic foot disease.

One aspect of neuropathy that is rarely given its due is the autonomic nerve involvement. These are nerves that have many important functions in the body and of these many functions, the ones that are especially relevant to our discussion, are that they regulate the blood supply to the limbs, determine sweating and also maintain the normal texture of the skin. When these nerves are affected in diabetes, it may lead to a reduction or even a complete absence of sweating in the feet and the lower legs. A reduction in sweating causes the outer layers of the skin to become dry and this makes the skin of the feet, especially the skin on the soles of the feet, to become brittle, liable to develop cracks which may form entry points for infecting bacteria. The skin also loses its ability to stretch and therefore any change in the shape of the feet also tends to cause the development of breaks and cracks in the skin.

In some people, the clinical picture may be completely reversed. With the skin showing excessive sweating. This again leads to the skin becoming "soggy" and macerated, thus, making it more prone to injuries and allowing for easy entry of bacteria

The autonomic nerves are also responsible for regulating the blood supply to the feet and this supply is affected when the nerves are involved. Surprisingly, feet that are affected with autonomic neuropathy may appear warm and have been shown to have an increased blood supply. This increase in the warmth leads many to mistakenly feel that the circulation in the limb is adequate. This is definitely not the true situation. It is known that although the total blood going to the leg and feet may have increased, most of this blood is shunted directly from the small arteries to the veins, bypassing the capillaries. It should be remembered that it is at the capillary level that the real function of the blood circulation takes place. It is here that the metabolites (oxygen, nutrients, waste products, etc.) are exchanged. The white blood cells and the other body mechanisms to fight off infection come into play at the capillary level. Therefore, although the total quantity of blood flow to the feet may appear to increase in diabetic neuropathy, this is of no real use and one could say that in practical terms there is a lack of blood supply to the feet.

The inadequate blood supply to the limb may be further compromised by the presence of peripheral vascular disease, which is much more common amongst diabetics than in a non-diabetic. In this condition, the arteries supplying blood to the legs and the feet are narrowed down by the atheroma formation. The earliest symptom of this could pain in the legs whilst walking, Some patients get pain at night when they are lying down but this can be relieved by hanging the foot over the edge of the bed and is increased if the patient gets up and walks around. The feet may feel cold, skin appears dry and parched, the nails lose their lustre and the small amount of hair on the toes may be lost.

I have said previously that the feet of a diabetic with autonomic neuropathy appear warm whilst with peripheral vascular disease, the skin is cold. This may sound confusing but it should be realised that diabetics do not have a clear cut demarcation between those that have only a neuropathy and those that have only peripheral vascular problems. Most of them have varying degrees of both, and the clinical picture would depend upon the relative severity of the two conditions in any individual patient. In any case, neuropathy and vascular disease, in severe forms, presenting in the same patient is dangerous because the patient becomes prone to painless ulcers which are quite resistant to treatment.

Whilst the nerve involvement and the peripheral vascular disease predispose to foot problems, there is usually seen a "trigger" or precipitating factor. This can be trauma, or infection or both. Therefore, the focus in preventing serious foot complications would aim at efforts to avoid trauma and infection to the feet or in the least, diagnose their presence in the very early stages so that adequate measures can be taken at a time when management of the patient would be simpler. One could make a point that avoiding or minimising neuropathy and peripheral vascular disease would be the best way of prevent- ing foot complication. I would definitely agree with this and some of these aspects have been covered elsewhere, but often a certain degree of nerve involvement is usually present in most people with diabetes and efforts to correct this have not proved to be too successful.

I would now like to take the discussion further and discuss ways and means to avoid trauma and infection in a foot already prone to complications.

Before we discuss these methods, there is one small aspect that I would like to clear up. There are some who feel that rigorous foot care is only important for those patients who are at special risk for getting serious foot complications. I thoroughly disagree with such an attitude and feel that all people with diabetes should have an intensive schedule of foot care, as it is not possible to clearly predict which patient is prone to serious problems and importantly, at what point of symptoms do we say that this particular patient should now have a more intensive foot care. At the same time, there are patients who are more prone to this problem and would need a much more specialised care and attention.

1. patients who walk barefoot.
2. patients with diabetic neuropathy.
3. patients with significant peripheral vascular disease.
4. patients who smoke or use tobacco in any form.
5. those with a foot deformity such as claw toes and hallux valgus.
6. diabetics with a history of previous ulcers or foot infections.
7. patients with abnormal gait.
8. those with significant skin and nail infections or deformitoes.
9. blind/partially sighted persons.
10. elderly patients ; especially those living alone,
11. diabetics with chronic renal failure;
12. patients with a high alcohol intake.