Managing Diabetes When You’re Sick

Let's face it ̶ nobody enjoys being sick.  When you have diabetes, illness adds an unwelcome layer of complexity to your day-to-day management.  You may be feeling miserable and want nothing more than to sleep, but you still need to stay on top of things by checking blood glucose (BG) and ketone levels, staying hydrated, and navigating food/fluids and medication.  It's a tall order, but with a few tricks and your handy insulin pump, you can make it through an illness much easier.   

Just having diabetes makes us a bit more vulnerable to infections, since elevated glucose levels provide an environment which allows bacteria and viruses to thrive.  Elevated BG levels hinder the ability of our white blood cells to fight infection, which makes it harder to overcome the illness.  That's why it's so important to keep BG levels in the target zone as best we can. 

Bacterial illnesses such as bladder or respiratory infections can cause your insulin requirements to rise, especially when they are accompanied by a high fever.  These types of infections tend to cause a major increase in insulin resistance, so basal insulin rates may need to be adjusted to compensate.  On the other hand, viruses like the common cold usually have less of an effect on BG levels and an increase in basal rate may not be needed or correction boluses alone might do the trick to keep BG levels in range.   Remember, ketones indicate that you are "lacking" in your insulin.  If your ketones are more than a small amount, this indicates that you do not have sufficient insulin to meet your body's basic needs for energy.   If BGs are elevated but ketones are negative, the problem may be resolved with extra bolus insulin.  Your doctor or diabetes educator can provide guidance on the amount of basal or bolus adjustment that's right for you. 

Some illnesses cause nausea, vomiting or diarrhea, and they may prevent you from eating.  Your first thought might be to suspend basal insulin on your pump, but doing so may put you into diabetic ketoacidosis (DKA).  Even when you aren't eating, your liver is still producing glucose, and insulin is needed to offset this effect.  In this situation, covering carbs may not be necessary, but correction boluses and basal insulin are still appropriate.   

(For those who use a pump, the extended bolus feature can be helpful when it is uncertain whether food eaten will stay down, because it can always be cancelled before the full amount of insulin is delivered.) During illness, it is important to stay well hydrated, and to regularly check for ketones ̶ ̶ particularly with nausea and vomiting.  You need extra fluids to compensate for vomiting, perspiration, and diarrhea.  If you become dehydrated, your insulin will not absorb properly below the skin, which can result in much higher blood sugar levels and, possibly, ketoacidosis.  If your urine is the color of light lemonade, you’re probably doing a good job of keeping yourself hydrated.  Dark yellow urine is often a sign of dehydration.  Your healthcare provider can advise you on what kinds of liquids are appropriate.   

Sometimes illness causes BG levels to drop.  This often happens with the “stomach flu” (viral gastroenteritis).  Low BGs can be a real challenge when you can't keep anything down. A reduced basal rate, but not complete basal suspension, may reduce the risk of hypoglycemia during such illness.   Discuss strategies to treat hypoglycemia ahead of time with your physician or educator.    

Make sure you have a plan for sick days, and follow your guidelines.  This plan should include how often to check BG, ketone levels and when to bolus for elevated BG.  The great thing about a pump is that it will track your insulin on board (IOB), giving you one less thing to worry about!  And the ketone checks will help you to gauge the amount of extra insulin that may be necessary.  Stay in touch with your healthcare team, and ask for their advice on how to eat, stay hydrated and rested. Bananas, rice, applesauce, and toast are easy to digest and are often recommended when patients are sick. And as always, have a source of fast acting carbohydrates such as glucose tablets on hand.  

It's also important to know when to say "uncle!"   If ketones are elevated for more than a few hours, you are having difficulty controlling your BG, you vomit more than once every 12 hours, have frequent diarrhea, or you just don’t know what to do, your healthcare provider can help you decide when it's time to head to the hospital for intravenous fluids, electrolytes, and other forms of treatment to keep you safe and get you on the road to recovery.   

Written by Gary Scheiner, MS, CDE and the Integrated Diabetes Services clinical team