| Diabetes |
Complications |
|
|
Complications caused by diabetes may be divided into acute and chronic, as described below. Acute Diabetic ketoacidosis Diabetic hyperosmolar syndrome Hypoglycemia Chronic Diabetic retinopathy This complication occurs in the retina of the eye, resulting from damages to the tiny blood vessels in the retina. The disease develops slowly. First, these tiny blood vessels swell and weaken. Some blood vessels then become clogged and do not let enough blood through. At this stage, you might not have any loss of sight from these changes, but they can be detected by a dilated eye exam. As the problem gets worse, new blood vessels grow. These new blood vessels are weak. They break easily and leak blood into the vitreous of the eye. The leaking blood keeps light from reaching the retina. You may see floating spots or almost total darkness. Sometimes the blood will clear out by itself. But you might need surgery to remove it. Over the years, the swollen and weak blood vessels can form scar tissue and pull the retina away from the back of the eye. If the retina becomes detached, you may see floating spots or flashing lights. You may feel as if a curtain has been pulled over part of what you are looking at. A detached retina can cause loss of sight or blindness if you don't take care of it right away. This complication occurs in the kidney, resulting from damages to tiny blood vessels in nephrons (functional units of the kidney). The function of the kidney is to filter the blood, remove the wastes, and excrete the wastes in the urine. The kidney disease takes many years to develop. In some people, the filtering function of the kidneys is actually higher than normal in the first few years of their diabetes. This process has been called hyperfiltration. Over several years, people who are developing kidney disease will have small amount of the blood protein albumin begin to leak into their urine. At its first stage, this condition has been called microalbuminuria. The kidney’s filtration function usually remains normal during this period. As the disease progresses, more albumin leaks into the urine. This stage may be called overt diabetic nephropathy or macroalbuminuria. As the amount of albumin in the urine increases, filtering function usually begins to drop. The body retains various wastes as filtration falls. Creatinine is one such waste, and a blood test for creatinine can be used to estimate the decline in kidney filtration. As kidney damage develops, blood pressure often rises as well. Overall, kidney damage rarely occurs in the first 10 years of diabetes, and usually 15 to 25 years will pass before kidney failure occurs. For people who live with diabetes for more than 25 years without any signs of kidney failure, the risk of ever developing it decreases. Diabetic neuropathy Diabetic neuropathy is a group of nerve disorders caused by diabetes. It may have the following symptoms: (1) numbness, tingling, or pain in the toes, feet, legs, hands, arms, and fingers; (2) wasting of the muscles of the feet or hands; (3) indigestion, nausea, or vomiting; (4) diarrhea or constipation; (5) problems with urination; (6) erectile dysfunction (impotence) or vaginal dryness; (7) weakness. Accelerated atherosclerosis Diabetes can accelerate atherosclerosis, the hardening and narrowing of the arteries. Atherosclerosis may lead to heart attack and stroke. Two-thirds of people with diabetes die of heart diseases. Mechanisms of Chronic Complications Excessive glucose can be toxic to the body. Two possible mechanisms are given below. Advanced glycation end-products (AGEs) Glycation is a chemical reaction in which sugar molecules (such as glucose) bond to proteins, lipids, or nucleic acids without the need of an enzyme. AGEs are the molecules produced by a chain of chemical reactions after an initial glycation. High level of glucose in the blood will produce more AGEs, altering the structures and functions of proteins and lipids on the blood vessel walls. In addition, AGEs may interact with their receptors on the surface of many types of cells (such as endothelial cells which line the blood vessel walls), triggering inflammatory or toxic reactions. Sorbitol-Aldose Reductase Pathway This pathway is also called polyol pathway in which glucose is reduced to sorbitol by aldose reductase. When the glucose level is high, excessive activation of the polyol pathway increases the concentrations of sorbitol and reactive oxygen species while decreases the concentration of nitric oxide. The reactive oxygen species are toxic to cells while nitric oxide has several beneficial properties for blood vessels.
References:
|