Two years ago, 10-year-old Katie Rush was having frequent and unsettling episodes of hypoglycemia – low blood sugar.
“I’d just feel really sleepy and hungry,” says the active Nashville seventh grader, who’d had type 1 diabetes since she was 3. “I wouldn’t remember anything that happened before I got low. I just felt really bad.”
Fortunately, at that time, insulin pumps were beginning to be prescribed to children, and Katie was fitted with one in the summer of 2001. Since then, “we’ve only had five or six of the kind of spells we’d been having twice a week,” says her mother, Dr. Meg Rush, assistant professor of Pediatrics at Vanderbilt.
Insulin pumps are among the recent technological and pharmaceutical marvels that are improving the lives of people with type 1 diabetes.
The battery-powered device, which is a little larger than a pager, contains a cartridge of rapid-acting insulin that is pumped through a plastic tube and into a needle inserted under the skin. With the help of a miniature computer, the pump can deliver precise amounts of insulin throughout the day, even when the patient is asleep.
Rapid-acting forms of insulin help improve blood glucose control because they more closely mimic the body’s normal insulin response after eating a meal. There are also long-acting forms of the hormone, designed for people who can control their blood glucose with once-a-day injections.
Patients still must test their blood glucose frequently, but they can program their pump to deliver an additional dose of insulin before snacks and mealtimes to help avoid the “highs” and “lows” of blood glucose that can occur with traditional insulin therapy.
“You have to be aware of how you feel,” Katie Rush says. “You have to monitor it closely.”
Of all the complications of diabetes treatment, hypoglycemia is perhaps the most frightening. “Often (patients) will prefer to have their blood glucose values running a little bit high in order to prevent hypoglycemia,” says Dr. Steven N. Davis, chief of the Division of Diabetes, Endocrinology and Metabolism at Vanderbilt.
Davis is trying to figure out why the body doesn’t compensate for insulin-induced drops in blood glucose, for example, by boosting secretion of glucagon, another pancreatic hormone that can stimulate glucose release by the liver.
A clue is cortisol, a stress hormone that appears to blunt the body’s ability to compensate for low blood glucose. Drugs that may block this cortisol effect are now being tested in humans. “The initial studies are really exciting,” Davis says.
In the meantime, new forms of insulin are being tested, including a form that could be inhaled, and efforts are underway to develop an insulin “pill.” Also in the pipeline: devices that can “read” blood glucose levels by shining infrared light on the skin.
The “holy grail,” of course, is the restoration of normal beta cell function. Whether or not that day ever comes, “we have spent the last eight years really encouraging her to know she can live a normal life,” Meg Rush says of Katie.
“This does make her different, but it doesn’t have to change her dreams.”