Uncommon Causes of Hypoglycemia
If your lows are baffling, consider these possible triggers
The shaky, sweaty, super-unpleasant symptoms of hypoglycemia may seem even worse if you can't pinpoint what caused the low blood glucose. You ate the same, you exercised the same, you took the same medication doses, so what could it be? Well, there are other possibilities. While these less common hypoglycemia triggers may not be on the tip of your tongue, they deserve consideration if you've gone down the list of usual suspects and still can't identify the culprit.
Tip No. 1, according to Belinda Childs, APRN, MN, BC-ADM, CDE, director of clinical and research services at Mid-America Diabetes Associates, is that "having a low isn't reason to panic." The key is to start doing some detective work to see if you can find the cause of a low. "If you can identify that common thing, then you try to prevent it next time," she says. "If you are having lots of lows, you are going to want to increase blood glucose monitoring. If you start developing patterns or notice an increase in the frequency of lows, that's when you've got to start looking at the less common triggers."
Lipohypertrophy and Scarring
Lipohypertrophy is a combination of fat and scar tissue, often caused by repeated insulin injections at one site. This tissue delays the body's absorption of insulin, so that blood glucose can go high right after a meal, before the medication has a chance to enter the bloodstream. Later, when the insulin is finally absorbed, blood glucose may go too low. Lipohypertrophy can usually be seen but sometimes can only be felt. It will feel smooth, round, and somewhat firmer than the surrounding tissue. Scarring can also be present without lipohypertrophy. The conditions are easily dealt with by switching injection sites. "The blood sugars will be more consistent because you've got out of that scar area," says Childs. She warns, though, that you may need to adjust your insulin dose when you make the move to sites with better absorption. Cameron Reimer, a 37-year-old with type 1 from Manhattan, Kan., says that where he puts his pump infusion set can affect how much insulin he needs. "Some areas of my body are more resistant," Reimer says, so he checks more frequently after switching sites and adjusts his insulin accordingly.
Having drinks can send blood glucose levels down overnight and into the next day. The effect can last "up to 24 hours after the alcohol," says Childs, who recommends a good bedtime snack and extra vigilance before going to bed and the next day in monitoring blood glucose levels. Alcohol consumption can lead to a dip in blood glucose because alcohol blocks the production of glucose in the liver. So once the liver's stores of glucose are depleted, a person who has had a lot of alcohol can't make more immediately. After imbibing, Reimer always checks his blood glucose. "If I'm 180 at night, I can wake up 100 points lower, which is scary for people who don't check," he says. "I'll eat something extra before bed."
"Kidney disease really plays havoc with the way the patient's insulin is utilized," says Davida Kruger, MSN, APRN-BC, BC-ADM, a nurse practitioner at the Henry Ford Medical Center. If the kidneys are damaged, they may not clear insulin effectively, leaving higher concentrations in the body. Plus, Childs says that kidney disease can lead to glucose lows because the kidneys can't make as much glucose as usual. "The kidney produces a third of the glucose the body makes," says Childs. "As the kidneys fail, the amount of glucose is reduced as well." The remedy is to adjust medications.
Thyroid and Adrenal Problems
People with diabetes are at an increased risk for hypothyroidism, a condition in which the thyroid gland produces too little thyroid hormone. Some studies estimate that close to 10 percent of people with diabetes develop hypothyroidism; it's much more common with type 1. The American Diabetes Association recommends that everyone with type 1 be checked at diagnosis for hypothyroidism with a simple blood test and, if the initial exam is normal, every year or two afterward. Thyroid hormone coordinates a variety of body functions; when there is too little, metabolism can slow down. The result is that medications tend to linger in the body, which can lead to overmedication and hypoglycemia. Childs suspects hypothyroidism when someone is having "consistent hypoglycemia." Hypothyroidism is treated with pills containing a synthetic version of thyroid hormone. Adrenal glands may also be damaged in type 1, leading to lower levels of glucose-raising hormones. Treatment involves replacing needed hormones.
Neuropathy can cause damage throughout the body, beyond the better-known nerve damage to feet and hands. The stomach contracts in response to signals from a special nerve; if that nerve is damaged, the stomach won't move digested food into the intestines for absorption with any regularity. This condition is called gastroparesis, which literally means stomach paralysis. "The thing about it is that patients may have it and not be diagnosed," says Kruger. "It's intermittent for some people. Sometimes it's on and sometimes it's off." Gastroparesis causes food and glucose to be absorbed into the body irregularly—so if you dose insulin with dinner, expecting normal absorption, you could go low because the meal may not be digested and absorbed until the next day. This can also lead to high blood glucose, so one clue that gastroparesis is causing lows is if there are unexplained highs as well. This condition can be managed with dietary changes, medications, and, in some cases, gastric pacing. This procedure involves putting a pacemaker in the stomach to facilitate digestion.
Because of changes in hormones, women with diabetes often experience a dip in blood glucose levels during the first 20 weeks of pregnancy. "You may need to lighten up on your meal dose and back off for a short period," says Childs. Women may tend to go low after delivery if insulin doses aren't scaled back.