It's a little known fact, but most people who have a lower limb amputated in Bermuda are diabetic.

The disease accounted for 79 percent of those amputations carried out at King Edward VII Memorial Hospital between April, 2006 and March, 2007.

Hospital statistics show 29 people had some portion of their lower limb removed. It may have been a toe, a portion of the foot or leg, or the entire leg.

And of these 29 people, 23 were a result of diabetes. That's an average of two locals a month losing a limb because of the disease.

Director of Emergency Services at KEMH, Dr. Edward Schultz, said the Bermuda picture is similar to that seem in the US where diabetes accounts for about 60 percent of all lower limb amputations.

Why are diabetics more prone to this? According to Dr. Schultz, it's because diabetics are at increased risk for developing foot ulcers.

"This is because diabetes affects their nervous system resulting in a loss of normal sensation in their feet. This increases their risk for skin injury that may result in an ulcer," he said.

For example, when a healthy person stands for an extended period they will instinctively shift their weight periodically. These may be small adjustments but they come as a result of nerve signals from the feet to the brain alerting the brain that too much pressure is bearing down on a particular point in the foot.

The brain, in turn, signals the person to shift a bit. If the pressure becomes too great, the person perceives their feet are sore and will rest.

The common local vernacular? "I'm just taking a load off my feet." It is a scientifically accurate and a wise thing to do.

In the case of a diabetic, the messages from the nerves in the foot never make it to the brain. This is called neuropathy. Because the messages never reach the brain, the brain doesn't alert the person to adjust their weight. The constant pressure on the foot causes a blister or sore which again, due to the loss of sensation in the foot, is not felt and may go unnoticed. The unattended sore may develop into an ulcer.

"Once the ulcer develops, the wound is more likely to become infected because diabetes interferes with our ability to fight infections," said Dr. Schultz.

In order to fight infection the body increases its metabolic rate. An increase in metabolic rate requires an increase in oxygen but the bodies of many diabetic patients are unable to provide the necessary oxygen increases.

This compounding complication is called vascular peripheral arterial disease. It is illustrated in the Albert Cann article also found in this week's Body & Soul.

Like Mr. Cann, many diabetic patients suffer severe vascular peripheral arterial disease. In this condition arteries carrying blood to the leg either become blocked or break. (Arterial disease may also occur in patients who smoke, have high blood pressure, or high cholesterol. Diabetics who have one or more of these risk factors greatly increase their risk for this condition.) The blockages and/or breaks mean that blood does not reach certain body tissue. Since oxygen is dissolved in blood, when no blood flows to the tissues they are starved of oxygen and die.

The areas that do not get blood will vary from person to person but typically the areas farthest away from the heart will be the casualties. If a blockage in an artery has caused the problem, the area affected will be that serviced by the blocked artery.

In some cases bypass surgery may be performed on an artery to clear the blockage in others angioplasty (where a tube is inserted into the artery and inflated to widen the opening, then removed) or stents (small wire device that holding the artery open).

In all cases, the aim of clinicians is to increase the amount of oxygen in the blood so that cells do not die.

Once cells die they cannot be revived. Gangrene is dead tissue. Diabetic patients who have peripheral vascular arterial disease may have wounds that do not heal and then become either infected or gangrenous.

Dr. Schultz pointed out that there are different types of gangrene. Wet gangrene presents more of a problem to the patient than dry gangrene. This is because wet gangrene is more likely to become infected causing more cells to die and the more of the limb to be lost.

Clinicians in the Wound Care Clinic keep a close watch on all their diabetic patients and are proactive in attending to them. Dr. Schultz said screening includes:

• Examining the leg — a cold foot is an indication off decreased circulation;

• Decreased pulse in the foot;

• Loss of hair on the foot;

• The colour of the foot;

• Ankle brachial index — here the blood pressure in the arm is compared to the blood pressure at the ankle they should be equal, if the pressure in the ankle is more than the pressure in the arm, it indicates an artery in the lower limb is obstructed.

"We are very diligent in trying to assess people at risk and refer them appropriately," he said. "At one point in the US they discovered half the amputees had not been evaluated. That does not happen here."

While the best efforts are made to save limbs, Dr. Schultz said it is common for diabetics to have a series of amputations. Hospital figures that reveal 23 diabetics as having amputations last year also show them having a total of 39 amputations in the same time period. Clearly that's more than one amputation for some of those patients.

A patient may first lose a toe, then a portion of their foot then the whole foot, and so on. "Our goal is to limit amputation," said Dr. Schultz. "We go out of our way to save as much tissue as possible."