What are diabetic complications?

Diabetes Mellitus is a medical syndrome of the endocrinology speciality. It is characterized by abnormal glucose metabolism in the blood. Diabetes Mellitus is divided into two types. These are: Insulin dependent diabetes Mellitus or IDDM and insulin independent diabetes Mellitus or IIDM.

Insulin is a small protein that is required for the transport of glucose inside the liver cells in order to be metabolized there to generate energy rich molecules in the form of ATP molecules or adenosine triphosphate. Glucose stimulates the release of insulin from the beta islet cells of the pancreas. Amino acids and sulphonylurea drugs also stimulate the release of insulin from the beta cells of the pancreas.
Diabetes Mellitus is thought to be of genetic origin but also autoimmunity has been suspected as a cause to diabetes. Calcium also induces the release of insulin by the beta cells of the pancreas.

The pancreas secretes two types of endocrine hormones. These are: Glucagon and insulin. Glucagon stimulates the degradation of the biopolymer glycogen into glucose units. Tumours of the islet cells of the pancreas are rare, but if they occur such as in the case of insulinoma. Insulinoma is manifested by oversecretion of the hormone insulin. This leads to hypoglycemia symptoms.

Glucagonoma is a tumour of the islet cells of the pancreas which is manifested as oversecretion of the hormone glucagon into the blood. The symptoms of this disorder are those of hyperglycemia and its associated diabetic symptoms.

Diabetic complications are divided into acute and chronic complications. Hyperosmolar nonketotic coma is one acute complication of diabetes that arise due to the high concentration of glucose in the blood or hyperglycemia. The high concentration of glucose in the blood renders an osmotic diuresis in which large amount of water is lost in the urine leading to dehydration. This in turn leads to higher osmolality of the blood plasma. This condition can lead to coma if left untreated. The treatment to this condition is the administration of supplementary amount of water to substitute for the water that was lost in the urine.

Another acute complication of diabetes mellitus which occurs in type I diabetes is the accumulation of ketone bodies in the blood and urine. This complication is called diabetic ketoacidosis. It occurs when the insulin level in the blood is greatly diminished. When the glucose cannot enter the cell for metabolism due to the lack of insulin another mechanism for the generation of energy starts to work.

This mechanism is the oxidation of fatty acids to generate energy rich molecules in the form of ATP molecules. Lipolysis or lipids degradation is stimulated in diabetes. Lipolysis of lipids form fatty acids and glycerol molecules. Fatty acids are then metabolized in the liver by an oxidation process which forms acetyl-coenzyme A. This species cannot enter the citric acid cycle in diabetic patients. Instead it is converted to ketones, especially acetoacetate and beta-hydroxy butyrate in addition to acetone.
Ketones can be carcinogenic when present in high concentration due to the formation of shiff bases with the amino groups of DNA bases. In the case of diabetic ketoacidosis the concentration of ketones in the blood and the urine is not significant to cause mutation.

Ketones form a source of energy for skeletal muscles and neurons of the brain which substitute for glucose as a source of energy in cases of diabetes or starvation. In diabetics ketones are also secreted in the urine giving it an acetone like smell.

Hypoglycemia is another acute complication of diabetes which occurs as a result of insulin which brings the concentration of glucose down in the blood causing hypoglycemia.

There are three chronic complications of diabetes mellitus. These are: first, diabetic microangiopathy or small blood vessels disease. It is manifested as thickening of the basement membrane of the capillaries. The organs most affected in this disorder are the kidney and retina of the eye and the skin and skeletal muscles.

The thickening of the basement membrane is associated with increasing the permeability of the blood capillaries which leads proteins in the urine in the case of the kidney. Another chronic complication of diabetes invloves the nerves of the body. This condition is called diabetic neuropathy. The lens of the eye is affected in diabetes causing cataract. It results from the accumulation of sorbitol in the lens tissue.

In addition to the acute and chronic complications of diabetes, there is also a general trend in diabetic patients to be susceptible to infection in addition to wound healing problems.