Question

Briefly describe the biochemical mechanism behind Diabetic ketoacidosis

Answer 1

Diabetic ketoacidosis is caused by critically low insulin level and is usually triggered when a daibetic patient undergo further stress such as infection, inadequate insulin administration or cardiovascular diseases. Glucose is the major energy source of the body. It comes form the digestion of carbohydrates and is carried by blood streams to various organs. Insulin is a hormone produced by the beta cells of the pancreas and is responsible for driving glucose into cells. When insulin is deficient, glucose can not enter the cells. It stays in the blood causing high blood sugar levels while the cells are starved. In response to this metabolic starvation, the body increases the level of counter regulatory hormones which have two major effects. First they produce more glucose in order to supply energy to the cells by breaking down glycogen into glucose and synthesizing glucose form non-carbohydrate substrates such as proteins and lipids. However, as the cells still can not use this glucose, this response only results in more sugar in the blood. As the blood sugar levels exceeds the ability of the kidneys to reabsorb, it overflows into urine taking water and electrolytes along with it. In a process called osmotic diuresis, this results in large volume of urine, dehydration and excessive thrust. Second, they activate lypolysis and fatty acid metabolism for alternative fuel. In the liver, metabolism of the fatty acids as an alternative energy source produces ketone bodies. One of these is acetone. Ketone bodies unlike fatty acids can cross the blood brain barrier and therefore can serve as a fuel for the brain during glucose starvation. They are however acidic and when produced in large amounts overwhelm the buffering capacity of the blood plasma resulting in metabolic acidosis. As the body tries to reduce blood acidity by exhaling more carbon dioxide, a deep and laboured breathing known as Kussmaul breathing may result. Also the overall potassium level of the body goes down as potassium is constantly excreted into the urine during osmotic diuresis.