Anybody can get sick from time to time, and people with type 1 diabetes (T1D) are no exception, even when they do their best to avoid it. For them, sick days are harder to manage due to their impact on blood sugar levels.
On sick days, the body can also become temporarily more resistant to insulin (i.e., the body doesn’t use insulin effectively and therefore requires higher doses). Certain types of infections (e.g., pneumonia, urinary tract infection) or treatments (e.g., cortisone) can also significantly increase the amount of insulin the body needs until the infection has cleared up. It is important not to overlook these impacts; in some cases, insulin needs can double in just a few days.
It’s hard to anticipate how your blood sugar will be impacted on sick days. That’s why you should make sure to check your blood sugar more often than you normally would (at least once every four hours, especially when you have blood ketone bodies).
Continuous glucose monitoring (CGM) systems make it easier to watch your blood sugar levels closely. However, some can be less accurate if you are dehydrated (e.g., vomiting, diarrhea, high fever) or if you take an interfering substance (e.g., acetaminophen, vitamin C supplements). If you have any doubts about the blood sugar measurement, it is recommended that you double check with a capillary blood sugar meter (finger prick).
In addition to monitoring your blood sugar levels, you should also watch your blood ketone level closely. Blood ketone bodies are released into your bloodstream when your blood sugar is high and your body doesn’t have enough insulin. Due to the associated risk of diabetic ketoacidosis, it is crucial that you keep an eye on your blood ketone body level.
You can measure your blood ketone level either with urine test strips or blood test strips used with a meter that looks just like a capillary blood sugar meter. The Freestyle Libre 1 and 2 CGMs can also measure blood ketone body levels, but only with the appropriate test strips.
If you are sick and your blood sugar remains high (above 14 mmol/L) or if you have symptoms such as nausea or vomiting, you should measure your blood ketone body levels regularly (once every two to four hours). The presence of blood ketone bodies means that your body needs more insulin.
Here are some examples of snacks with carbs that are easy to digest: fruit sauce, rehydration drink (e.g., Gastrolyte), regular popsicle, regular fruit gelatin (e.g., Jell-O®), juice, bread with or without jam.
To help avoid dehydration and to help your kidneys flush out the excess sugar through your urine, it’s important that you drink a lot of water (approx. 250 ml or 1 cup per hour).
- Long-acting insulin or basal rate (insulin pump): Keep taking your usual doses, but you might have to gradually increase your doses or basal rates (if using an insulin pump) if your blood sugar remains high.
- Mealtime rapid-acting insulin: Adjust your dose according to your carb intake. If you have symptoms such as nausea or vomiting, it might be better to take your insulin after your meal, exceptionally.
- Rapid-acting insulin to correct high blood sugar (correction bolus): Correction boluses are usually calculated according to a correction factor that indicates the impact (in mmol/L) of one insulin unit on your blood sugar. Since you may be more resistant to insulin when you’re sick, you might have to inject a higher bolus to bring your blood sugar down. However, be careful not to take correction boluses too close together; this could cause insulin stacking and lead to the reverse situation (hypoglycemia).
Insulin needs vary from person to person. It is very important that you watch your blood sugar carefully before taking any action, and if you have to increase your insulin doses because your blood sugar remains high (in spite of your usual insulin doses and correction boluses), that you do so gradually.
- Blood sugar above 20 mmol/L and blood ketone body level remaining higher than 1.5 mmol/L with symptoms (e.g., nausea, vomiting) even after taking insulin.
- Blood sugar above 20 mmol/L and blood ketone body level remaining higher than 3.0 mmol/L.
- Ongoing vomiting and difficulty drinking.
- Fever remaining higher than 38.5°C (101.3°F) for more than 48 hours.
Make sure you have all the supplies you need: ketone body test strips, syringes and insulin pens in case of a pump malfunction, insulin back-up (vials, cartridges, pens), etc.
The BETTER project focuses on people with type 1 diabetes in Quebec. We aim to provide a better voice for type 1 diabetes and to improve access to treatments and new technology with the BETTER registry (a kind of census). If you or your child live with type 1 diabetes in Quebec, we invite you to sign up and help us make a difference. This will also give you access to our monthly webinars. The next one will be on Financial aspects and type 1 diabetes. Learn more »