Diabetic feet need extra care. Even small foot problems can become serious for people with diabetes. Always check with your doctor before treating a foot issue at home.
The diabetic foot, also known as Charcot foot, is a complication that occurs in people suffering from diabetes mellitus. If left untreated, it can lead to a potentially crippling situation. High blood sugar levels in the body trigger a condition known as neuropathy or extreme nerve damage. The bones in the feet soften and may fracture easily. Since the nerves in the area are damaged, the patient experiences a loss of sensation in the feet, and is unable to feel pain or respond to stimuli. The nerve damage also causes the muscles in the region to be unable to function any further. With continued movement, the wobbly bone structure in the feet sustains trauma repeatedly until the joints collapse, twisting the foot into an abnormal shape. Due to the complete loss of sensation in the affected area, the patient is unaware of the gradual deformity of the foot until the entire arch collapses, making walking an impossible task.
The occurrence of diabetic foot ulceration is not as infrequent among patients as it was previously thought to be. New studies reveal that people afflicted with diabetes have a 25 percent risk of developing foot ulceration. The annual reported incidence of the condition has-been as high as 10 percent in recent years. There are two underlying causes that contribute to this condition, namely, peripheral neuropathy and ischemia, brought on as a result of peripheral vascular disease. Let us examine these causes below.
Peripheral Neuropathy
Peripheral neuropathy, or damage to the peripheral nervous system, is one of the leading causes of diabetic foot ulceration, responsible, as studies show, for more than 60 percent of all foot ulcers in diabetes. This condition is itself triggered by improper metabolism in the body resulting in hyperglycemia, or high blood sugar. So how does it happen" Scientists have identified a mechanism known as the polyol pathway where high blood sugar levels increase the action of two enzymes—aldose reductase and sorbitol dehydrogenase. This causes glucose in the cells to convert to the sugars fructose and sorbitol.
As a direct consequence of this conversion, excess glucose conversion products start to accumulate inside healthy nerve cells, impairing its functioning. Also, this conversion uses up and depletes the levels of a chemical known as nicotinamide adenine dinucleotide phosphate, which is essential in regenerating the critically important antioxidant molecule, reduced glutathione, inside the cell. Antioxidants are very important in detoxifying cells by protecting them from the oxidative actions of metabolic waste. This therefore leads to oxidative damage to nerves and cells. Hyperglycemia also results in the accumulation of other abnormal molecules in the cells, all of which lead to damage to the endothelial cells, which line the blood vessels. Over time, this leads to narrowing and reduction of the flow of blood through the arteries. Eventually, the nerves and cells in the feet begin to die as a result of ischemia and oxidative stress, causing severe ulceration and bone abnormalities.
Nerve damage in diabetic patients attacks the autonomic, motor, and sensory nervous systems. It impairs the distribution of nerves in the feet and also paralyzes major foot muscles, preventing extension and flexion. This leads to the formation of foot deformities where the bones jut out at crucial pressure points in the foot. With constant movement, the bony protrusions push through the skin causing ulceration and breakdown.
Neuropathy, or nerve damage, also reduces the functioning of oil and sweat glands in the feet. In time, the foot is unable to naturally moisturize the top layer of skin, causing it to become increasingly dry and cracked. This makes the skin on the feet highly susceptible to breaks and tears, eventually leading to severe infections. Diabetic patients who are afflicted with neuropathy also come to lose all sensation in their feet. As a result, festering wounds and foot deformities go unnoticed and worsen with time, leading to a gangrenous stage where amputation may be the only solution.
Peripheral Ischemia (Arterial Disease)
According to recent studies, arterial disease is a factor in nearly half of all foot ulceration cases, making it the second most significant contributing factor after neuropathy. In diabetes, this commonly affects the peroneal and tibial arteries that pass through the calf muscles. The build-up of high sugar levels impairs the function of the endothelial cells, and causes smooth cell abnormalities. The dysfunction of the endothelial cells prevents normal vasodilation, causing the arteries to constrict. Hyperglycemia also increases the production of a vasoconstrictor, called thromboxane A2, which leads to the formation of blood clots in the arteries of the heart. There are also alterations to the heart’s extracellular matrix causing stenosis or severe constriction of the main vascular arteries. Other contributing factors to peripheral ischemia include hypertension, smoking and hyperlipidemia. All these factors cumulatively result in ischemia, which is the inadequate supply of blood to the tissues of the foot, and increases the risk of ulceration in diabetic patients.
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