Autopilot Lost

Friday, March 23, 2007

We live in a very narrow range of normal. In that range, the body performs well, but slip outside those norms and the body spirals slowly out of whack. We take most of the internal controls for granted since they are on autopilot, but many people need to fly manually.

The body’s cells need two energy requirements to function. The blood stream delivers both oxygen and glucose to the front door of the cell, but while the oxygen is invited in, the glucose needs a key to open the door. The insulin molecule is that key. When we eat, the body senses the levels of glucose in the blood stream and secretes just the right amount of insulin from the pancreas to let cells and he body function.

Diabetics don’t have the luxury of that autosensing. They need to balance the amount of glucose their body takes in with the amount of insulin that needs to be injected. Not enough insulin and the glucose levels in the blood stream start to rise; too much and they plummet.

The hypoglycemia (hypo=low, glycemia=glucose in the blood) consequences are easy to understand. No energy source, no function and the first organ to go is the brain. It needs power to run and without glucose, the brain turns off quickly. Confusion, lethargy, coma occur in short order. It’s interesting that brain cells don’t need insulin to open their doors to glucose, so when people develop low blood sugars, they waken almost instantaneously to treatment. Blood sugar is one of the first things checked on scene of a comatose patient, because it’s so easy to fix and very embarrassing for a paramedic to miss.

And sometimes, too much is too much. High blood glucose levels, or hyperglycemia , cause a cascade of effects that are damaging to the body in the short and long term. Long term, abnormally high sugars cause damage to blood vessels leading to a variety of badness including but not limited to anything that needs a blood supply: heart attack, stroke, kidney failure, blindness and amputations. Add increased risk of infection and there is great incentive to keep sugars tightly under control.

Rise in glucose because of lack of insulin has short term consequence as well. Cells can’t get at the sugar floating in the blood stream, so they turn to alternative fuel sources to function, but the waste products, ketones, make the body more acidic. At the same time, the kidneys sense too much glucose and start spilling it into the urine. Unfortunately, water follows and dehydration quickly occurs. The body says drink more, but the kidneys rid the body of the water faster. Now comes the downward spiral. The body becomes more acidic and dehydrated, electrolytes get messed up and all hell breaks loose. The technical term: diabetic ketoacidosis. The treatment: fluids and insulin and education for prevention.

People with diabetes live in their narrow range of normal. Tight control with multiple daily glucose testing and using insulin more frequently during the day to mimic normal body function allows those with diabetes to live routine lives. Autopilot treatemtns are getting better. How good should diabetic therapy be? When we no longer marvel at elite athletes who are diabetic and when they don’t they don’t become a story.

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