Some Forms of Diabetes Don’t Play to Type
A look at LADA, MODY, cystic fibrosis–related diabetes, and more
Diabetes doesn’t always look exactly like the type 1, type 2, or gestational varieties. Read on to learn about five different kinds of diabetes that don’t play to type—and some people who are living with them.
Latent autoimmune diabetes in adults, or LADA, is slowly developing autoimmune type 1 diabetes that occurs in adulthood. While type 1 diabetes typically appears in children, has a rapid onset, and requires insulin use immediately, LADA appears in adults, is slow moving, and might not require insulin for months or years. “It is an autoimmune type of diabetes, but with LADA, the onset and progression are slower,” says Regina Castro, MD, an endocrinologist with the Mayo Clinic. “It’s a gradual destruction of the beta cells that make insulin.”
The slow death of insulin-producing cells and adult onset are the main differences between LADA and typical type 1. Because LADA is slow moving, people with the condition often are diagnosed at first with type 2 diabetes. LADA can also include insulin resistance as in type 2, in which the body isn’t able to properly use what insulin it does make and glucose levels rise. Some people refer to LADA as “type 1.5, to imply it’s somewhere between type 1 and type 2 in that it has symptoms that resemble both,” Castro says.
Anne Peters, MD, a professor of medicine and director of the University of Southern California Clinical Diabetes Programs, is very familiar with LADA but knows there’s more to learn. “The amount we don’t know exceeds the amount we know,” Peters says. For example, one LADA patient might need to start taking multiple daily insulin injections within a few months of diagnosis. For another patient, metformin pills may be enough to control blood glucose levels for a long time.
But in LADA, the person who doesn’t need insulin therapy (yet) still has a form of type 1 diabetes. “Twenty years ago, we couldn’t measure the antibodies [present in LADA patients],” Peters says. “We assumed type 2.” Those antibodies aresigns of the body’s immune response going haywire, destroying the insulin-producing beta cells in the pancreas. But now lab tests, such as for insulin antibodies or islet cell antibodies, can indicate if the autoimmune system is under attack, a hallmark of type 1.
Charli Guerin, 30, of Lenexa, Kansas, knows that story all too well. In August 2010, Guerin passed out due to high blood glucose. Her doctors diagnosed her with type 2 diabetes and prescribed metformin. Guerin, however, began losing weight without explanation, and says she was “feeling really crummy all the time and worn out.” In July 2012, she went to a new endocrinologist, who ran a panel of tests, including an antibody test. By the next morning, her endocrinologist had her rush to the hospital—Guerin’s lab tests were back, and she was in diabetic ketoacidosis (DKA) with a LADA diagnosis. She needed IV fluids and to start using insulin.
Like Guerin’s months-long journey to intensive insulin therapy, the development of LADA may follow a meandering route. “So many things don’t fit into the ‘type 1’ category,” she says.
That can be frustrating for patients, who often struggle to find specific information on LADA. That could be because many organizations, including the American Diabetes Association, don’t recognize LADA as being different from traditional type 1 diabetes, says Castro. Clinically, that makes sense because treatment should be individualized and, in the long run, people with LADA almost always need insulin.
Various genes contribute to type 1 and type 2 diabetes, but some forms of diabetes depend on a single gene. There are 12 known types of diabetes caused by the mutation of different single genes, all under the umbrella of MODY, maturity-onset diabetes of the young. MODY is typically diagnosed in adolescence or early adulthood and can look like type 1 or type 2 diabetes. Some people with MODY might be thin; others might be overweight. Some could be in DKA at diagnosis, while others might just have lifelong, slightly elevated blood glucose levels, with no developing need for insulin treatment. The types of MODY are as varied as the genes they’re caused by, says Louis Philipson, MD, PhD, FACP, professor of medicine at the University of Chicago and director of the Kovler Diabetes Center. Kovler is the leading MODY research center in the United States and host of the nation’s MODY registry.
Because the different types of MODY are so diverse—and because the only way to be sure a patient has MODY is to do genetic testing—it’s hard to know how many people actually have MODY. “The biggest problem is identifying [the patients],” Philipson says. “It does require some perseverance to get an answer, and way too many people are giving up due to barriers in getting to a diagnosis.” He notes that if doctors have only 10 or 11 minutes on average with a patient, they will try to find the most likely diagnosis first, which would be type 1 or type 2 diabetes. Genetic testing for MODY might be prohibitively expensive; it’s not typically covered by insurance. If one family member has had genetic testing and the specific mutation is known, however, other family members can have tests run for that specific mutation, making testing cheaper. And testing specific genes is worth it—a MODY diagnosis might mean a patient needs to take only a single pill a day for treatment, rather than starting insulin therapy, Philipson says.
Michael Eizenga, 31, of Chicago, has a typical MODY story. He was diagnosed with type 1 diabetes at 15 years old, during a routine physical for soccer. But he never showed the classic signs of diabetes, and his A1C always hovered around 5.5 percent. Nevertheless, Eizenga carried on with multiple insulin injections and blood glucose tests every day, until a colleague whose daughter saw Philipson suggested Eizenga get tested for MODY.
“We had the genetic testing done, a little cheek swab, and I didn’t hear back for several weeks,” Eizenga says. “The genetic test came back, and it was positive for the MODY-3 mutation. I didn’t know what that meant.” What it meant was, Eizenga no longer has to inject insulin: He takes one glyburide pill at each meal. He has to test his blood glucose only twice a day. “It’s been life-changing. I just feel so fortunate that they found it,” he says.
Insulin-Resistant Type 1
Type 1 but taking metformin? It sounds unlikely, but for some type 1 people, using this traditional type 2 medication helps them control insulin resistance in type 1 diabetes.
In most patients with insulin resistance and type 1 diabetes, doctors see the signs that are usually linked to a greater risk of developing type 2 diabetes, including abdominal obesity, low HDL (“good”) cholesterol, high triglycerides, and a family history of type 2. These people are at a higher risk for cardiovascular and renal disease. But in such patients, the beta cells of the pancreas have already stopped producing insulin, sometimes decades earlier.
“[Research has] led us to believe that there are a subgroup of type 1 individuals who would have developed type 2 and have the genetic background [for] ‘double diabetes,’ or insulin resistance,” says Trevor Orchard, MD, professor of epidemiology at the University of Pittsburgh Graduate School of Public Health. “They’re clearly a type 1 subgroup … but with risk factors that we normally see with insulin resistance and metabolic syndrome,” a cluster of risk factors for cardiovascular disease and type 2 diabetes.
Another risk factor for insulin-resistant type 1: polycystic ovarian syndrome, or PCOS. Dana Reeher, NP, 30, of Sharon, Pa., learned that upon her PCOS diagnosis in 2008. She had been diagnosed with type 1 diabetes in 1989. Insulin pump therapy, she says, worked for her, but over time she seemed to need much more insulin, she was gaining weight, and her blood glucose was still very high. PCOS patients have too much androgen, which can lead to insulin resistance and weight gain. More than half of all women diagnosed with PCOS will develop type 2 diabetes or prediabetes before age 40, according to the Office of Women’s Health. Because Reeher already had type 1 diabetes, her case is not typical.
Her treatment, however, has been pretty straightforward—she continues with insulin pump therapy, takes metformin, counts carbohydrate grams, and exercises more regularly than before. She’s also trying to find more answers on how to get better glucose control. “I’m really pleased with my weight loss and A1C,” she says.
There’s no one tried-and-true way to treat insulin resistance in type 1 patients. Several studies are under way on whether metformin (which reduces blood glucose levels by decreasing the liver’s glucose output and improving the muscles’ use of glucose) is the best treatment; so far it seems to be. Other traditional type 2 treatments, such as sulfonylureas, which help the beta cells make more insulin, won’t work because the type 1 pancreas no longer produces enough insulin or any insulin. Orchard says the best bet is making classic lifestyle modifications: controlling diet and increasing exercise (which can increase insulin sensitivity). “We should be as physicians more active in treating in the more traditional way: lifestyle, diet, and activity,” he says.
And while weight loss is often part of the treatment plan for people with type 2 diabetes, Orchard cautions that weight change in type 1 diabetes is complicated—a little weight gain with better blood glucose control is probably good, while weight loss with high blood glucose levels might mean a patient isn’t getting the right amount of insulin. It’s important to individualize the treatment plan.
Cystic Fibrosis–Related Diabetes
Sometimes diabetes is triggered by another malady. It’s increasingly common in people with cystic fibrosis, a genetic disease that causes abnormal composition of some of the body’s secretions. Cystic fibrosis’s most well-known symptom is a buildup of mucus in the lungs that must be physically expelled to clear the lungs for breathing (often with a special vest that vibrates and applies pressure to the chest, breaking up the mucus). But cystic fibrosis also affects the body’s secretions of digestive enzymes and insulin from the pancreas. That’s why more than half of the 30,000 Americans living with cystic fibrosis will also develop diabetes, says Antoinette Moran, MD, professor and division chief of pediatric endocrinology at the University of Minnesota.
“[Cystic fibrosis patients] make a little bit of insulin, but not enough insulin, and by the time they are adults, more than half of the patients have cystic fibrosis–related diabetes,” she says. “I think of them when I’m treating them almost like a type 1 diabetic in the honeymoon stage: They’re making a little bit of their own insulin.”
Cystic fibrosis patients who have diabetes must monitor their blood glucose levels and carbohydrate intake even more rigorously than other diabetes patients. Because of CF’s thick secretions that clog the lungs and digestive system, patients chronically fight inflammation and infection, and that can take many calories—3,000 or more each day. “It’s absolutely critical that they keep up their body weight and muscle mass,” Moran says. “I can’t tell you how many cystic fibrosis patients have gotten terrible advice, advice that could kill them, saying to avoid carbohydrates, avoid fat. We form our diabetes management around their cystic fibrosis needs.”
Diabetes treatment can help patients manage their CF, too. Lorraine Barnes of Nottinghamshire, England, found that to be the case with her son Joseph’s treatment. Joseph Barnes, 10, was diagnosed with CF-related diabetes in 2012. “[If] any other parents of children are worried about a CF-related diabetes diagnosis, I would say that any added complication of cystic fibrosis which is diagnosed and treated correctly is a good thing,” Barnes says. “Treatment [of diabetes] can improve lung function and improve weight gain.”
Life Without a Pancreas
What if you knew you were going to get diabetes before it happened? It might sound strange, but people who have planned pancreatectomies (the partial or complete removal of the pancreas) know ahead of time: A partial pancreatectomy increases your chances of developing diabetes. A total pancreatectomy guarantees it.
People have pancreatectomies for a variety of reasons, says Nancy Davidson, RN, MSN, CDE, of the Mayo Clinic. Accidents that damage the pancreas are one reason for removing the organ. Tumors, cancerous or benign, are another. Chronic pancreatitis, a condition in which the pancreas is inflamed and doesn’t get better, can lead to a host of problems, and pancreas removal may be necessary.
But of course, when you remove an organ, you remove the ability of the body to perform certain life-sustaining functions. With the pancreas, that includes secreting insulin and some digestive enzymes, says Davidson. When pancreatectomy results in diabetes, she says, treatment for it is not really different from treatment for traditional type 1 diabetes—in fact, knowing diabetes might be a result can lead to earlier and better education. Before surgery, a doctor counsels patients, and in the hospital they get diabetes education and learn how to inject insulin. “Later down the line we have them coming in for an intensive insulin program,” Davidson adds. These people also need to take digestive enzymes to help them process their food, which can also affect their blood glucose.
Paula McBride, 47, of Huntsville, Ala., opted to have a pancreatectomy in March 2012 after years of pain due to pancreatitis and pancreatic divisum, a congenital defect involving the pancreatic ducts, the passages that carry digestive enzymes from the pancreas to the intestines. She lives with diabetes as a result of the surgery. Before the surgery, McBride says, “I couldn’t eat or drink and had an IV. Now it’s better. I can eat and drink and do what I want to do. I’m living a much better quality of life, and I’m very happy that I did the surgery, even with the diabetes.” She manages her diabetes with diet, exercise, and insulin pens, and hopes to get an insulin pump within the next year.