The Serious Side of the Flu for People with T1D


The flu can increase the risk of diabetic ketoacidosis (DKA), a serious acute complication of type 1 diabetes (T1D) that results from too little insulin

DKA is normally seen in states of prolonged fasting or starvation.  The body shifts metabolism from primarily using glucose to using an alternate fuel pathway, ketones, derived from fatty acids. A key signal for this shift is very low insulin levels. However, in T1D this shift can happen within a few hours when too little insulin is administered, often in the setting of another illness such as an infection or flu (the basal insulin in a basal/bolus insulin regimen typically blocks the production of ketones). The ketones build up in the blood stream and make the blood more acidic and can be associated with dangerous shifts in many of the essential electrolytes.

Usually the low insulin levels that can result in DKA are also associated with a rise in blood glucose (typically above 250 mg/dL), which can be an early warning signal. Other signs of DKA include flu-like symptoms (feeling tired, weak, aches, nausea or vomiting, abdominal pain), dehydration and also a fruity smell to the breath with more rapid breathing, which happens when the body is trying to eliminate the ketones and acid. In more severe cases there can be confusion or coma. Unfortunately, DKA is a relatively common occurrence at the time of initial diagnosis of T1D and 4.8% of adults living with T1D reported one or more episodes of DKA in the past year. Although treatment of DKA has improved greatly, it still accounts for about 1 out of 14 deaths in people with T1D.

Seven things that you can you do:

  • Talk about DKA with your diabetes care team! Often we talk a lot about DKA around the time of diagnosis, but not so much in the years afterward.
  • Discuss whether testing for ketones (urine or blood) during times of illness or high blood sugar is right for you.
  • Make sure you have the supplies that you need to monitor and care for your diabetes, including, if appropriate, ketone test strips. That way, you will not have to try to obtain them when you are under the weather.
  • Ask about sick day management- when you are feeling sick – be sure to continue taking insulin, although it may need to be reduced from your usual doses to avoid hypoglycemia.
  • Ask your diabetes care provider about what do about a missed insulin injection (especially basal insulin) or pump insertion site failure- often covering with some short-acting insulin until your next basal insulin injection can prevent DKA.
  • Make a plan before you are sick about when to call your diabetes care team for advice and when it is best to head to the emergency room.
  • Finally, sit down with your close friends or family members to ensure they are knowledgeable about DKA, as an important component of overall diabetes management. Like most things with T1D, it is important to keep the dialog going!