Etiopathogenesis of Diabetes Mellitus

What are the complications? The basic phenomenon in diabetes mellitus is the destruction of the beta cell mass that leads to deficiency of insulin. There are three linked mechanisms in the Etiopathogenesis of diabetes mellitus. The first is genetic susceptibility; second is auto immune factors and the third is environmental factors. In genetic susceptibility, it has been observed in identical twins that if one twin has DM, there is more than half a chance of the second twin developing it. Studies on both animals and humans have shown various immunologic abnormalities as far as auto immune factors are concerned. There is presence of islet cell antibodies against glutamic acid decarboxylase and insulin. There is occurrence of lymphocytic infiltrate around the pancreatic islets and this is known as insulitis. Environmental factors include some viral infections that precede the onset of the disease like mumps and measles. Early exposure to bovine milk proteins leads to auto immune processes and chances of DM setting in. Obesity and hypertension and lack of physical activity play an important role in modulating the disease. Complications of Diabetes Mellitus The complications are less severe in people who have blood sugar levels that have been well controlled with medication. Wider health problems start creeping in with deleterious effects of diabetes including smoking, elevated cholesterol levels, obesity, hypertension and lack of regular exercise. Mechanisms of Chronic Complications Chronic elevation of blood glucose levels leads to damage of blood vessels and this is known as angiopathy. The endothelial cells that line the blood vessels take in more glucose than normal as they do not depend on insulin. They form more surface glycoproteins than normal and cause the basement membrane to grow thicker and weaker. These are related microvascular diseases when there is damage to the smaller blood vessels and macrovascular diseases when there is damage to the arteries. It has been recorded that forty per cent of all people suffering with diabetes mellitus develop neuropathy even after controlling their blood sugar levels. Auto immune relations destroy the beta cells of the pancreas and they may also cause retinopathy and nephropathy. Genetics also play a role in causing complications. Severe type of chronic complications may lead to diabetic cardiomyopathy, causing damage to the heart muscle. This leads to impaired relaxation and filling of the heart with blood. This is known as diastolic dysfunction. This is the eventual reason for heart failure. Diabetic nephropathy damages the kidney and leads to chronic renal failure. Diabetes mellitus is a common cause of kidney failure in adults in the developed world. Diabetic retinopathy results in growth of poor quality blood vessels in the retina and there is a mascular edema or a swelling of the macula, leading to loss of vision or blindness. Another complication is the diabetic foot which results out of a combination of sensory neuropathy and vascular damage. It also increases risk of skin ulcers and infection, leading in extreme case to necrosis and gangrene. This is the reason why diabetics are prone to more leg and feet infections and why it takes very long for them to heal from such wounds. Restrictive lung effect is known to be linked with diabetes mellitus. It could result from chronic low grade inflammation of tissue and micro-angiopathy.