TOE-GETHERNESS
From cause factors, to diagnosis, to foot care, the diabetic foot's history
By Michelle Ciriacruz
DIABETES MELLITUS COULD EITHER COME IN AS SILENT AS A CAT OR AS RAGING AS A BULL. MANY DIABETICS DO NOT REALIZE THEIR CONDITION UNTIL SOME HEALTH CRISIS WOULD MAKE A SORRY END TO ALL THEIR DENIALS OF ILL HEALTH.
Like hypertension, which causes organ damage if left unchecked, the excessive levels of blood sugar is responsible for various cascades of reactions in the body that eventually lead to diabetic complications.
One of the most shattering is damage to the lower extremities. The diabetic patient is extremely vulnerable to foot ulcers, poor wound healing, and gangrene.
This is what what's commonly known as the diabetic foot. If neglected, or inappropriately managed, the diabetic foot might very well turn out to be the "amputated foot."
In My Foot
The rate of amputation among diabetics is very high. In the United States, diabetes mellitus is the leading cause of nontraumatic amputation. Because of the microvascular and neuropathic problems associated with diabetes, approximately 15 percent of diabetics will develop foot ulcers.
The symptoms usually involve damage to the motor and sensory nerves and poor blood circulation in the small blood vessels of the lower extremities.
Evidence points to chronic hyperglycemia as a progenitor to the cascade of symptoms. Three major studies have supported this link. The Diabetes Control and Complications Trial (DCCT), United Kingdom Prospective Diabetes Study (UKPDS), and the Kumamoto study in Japan all demonstrated that intensive glycemic control could reduce the risk of retinopathy, nephropathy, and neuropathy among diabetics. (The UKPDS also highlighted the importance of strict blood pressure control to reduce both macro- and microvascular complications.)
With sensory nerve functions impaired, the sense of pain that normally informs us of and protects us from further injury is diminished or absent. This paves the way for repeated major or minor trauma to the foot, often leading to infection despite preventive measures. And because wounds heal slowly and poorly (sometimes taking weeks or months), a blister can worsen to something that is already gangrenous.
Furthermore, as the skin of the diabetic foot could become very dry, it becomes prone to peeling and cracks-another potential path to infection.
Motor and sensory neuropathy also leads to abnormal foot biomechanics. The sense of how the feet fall and positioned on the ground while walking does not work very well anymore in diabetics with neuropathy. They tend to put too much weight on high-pressure areas under the foot, which causes the buildup of calluses.
As nerve damage also causes structural changes in the foot, like hammer toe, claw toe deformity, prominent metatarsal heads, acquiring proper fitting for the foot is often a problem. In the care and management of the diabetic foot, wearing proper footwear is very important.
In the 2001 annual convention of the Philippine Diabetes Association, Dr. Constancio de la Cruz, a consultant physiatrist at Dipolog Medical Center, stressed this. He explained that the appropriate footwear should have extra depth (roomy toe box), low heeled, is custom-modified fits the shape of the foot correctly), and the inside lined with fabric to provide cushioning and prevent the tougher outer shoe material from rubbing against the foot, which causes blisters or break open scar tissues.
In Circulation
Poor circulation in the foot and peripheral nerve deterioration normally go hand in hand, as the nerve cells need to be supplied with oxygen from the small blood vessels.
Smoking is one more serious threat to the feet, as it worsens the problem of poor blood circulation. The nicotine in tobacco constricts blood vessels and cuts the amount of oxygen reaching the tissues. When diabetologist Ricardo Fernando spoke about the diabetic foot's microcirculation dysfunction in the fifth Asian Congress for Microcirculation last February, he shed some light on the diabetic's already existing predisposition of the small blood vessels to narrow, and the presence of factors that hamper the flow of red blood cells through them.
He first pointed out why red blood cells are able to pass through capillaries with smaller diameters.
"The red blood cell is obligated to deliver oxygen and nutrition to the periphery, where the diameter of your capillary [could only be] three microns. How does it do it? Through the process of deformability. The red blood cell deforms, it is able to pass through capillaries that are even smaller than its diameter," he explained.
In a diabetic situation, the red blood cell loses some of its flexibility and the plasma through which it swims about becomes thickened. This then interferes with normal blood flow in the peripheral blood vessels.
Also, Fernando explained, the diabetic situation somehow upsets the balance between chemicals that regulate platelet aggregation. "There is a standing balance normally between prostacyclin and thromboxane A2 (natural compounds playing major roles in blood clotting)." When prostacyclin is inhibited compared with the generation of thromboxane A2, "there is tendency for [blood] clot formation in the diabetic patient," he continued.
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