When the weather turns cold, the flu virus starts making trouble. For individuals living with diabetes, the flu can be much more than a passing annoyance. It can cause serious complications and disrupt a person's ability to maintain healthy glucose levels.

Flu and diabetes are a tricky combination, but having a diabetes care plan in place is key to beating the flu virus successfully.

When the Flu and Diabetes Meet

The Mayo Clinic explains the effect that illness has on people with diabetes.

When you're sick, your body manufactures its own additional glucose to provide energy to fight the infection. The flu may also cause your body to release the stress hormones adrenalin or cortisol, which reduce the effectiveness of insulin, the hormone responsible for lowering glucose levels. Combined, these two effects can result in high glucose levels that's difficult to bring back to normal levels.

With insulin levels low, your body can't effectively use the glucose circulating through it. Instead, it turns to using ketones for energy. The combination of ketones and high glucose levels can make your body too acidic to function properly. This is called diabetic ketoacidosis, and it's an emergency that requires immediate medical attention.

The flu may also trigger another condition, called hyperosmolar hyperglycemic nonketotic syndrome (HHNS), in which your glucose levels are so high, your body essentially becomes dehydrated trying to compensate. It's also a life-threatening emergency.

These conditions are concerning, but you can avoid them by following a detailed diabetes management plan.

Preventing the Flu

Everyone should follow general precautions for preventing, recognizing and treating the flu, but people with diabetes need to take special care.

The Centers for Disease Control and Prevention (CDC) encourages people with diabetes to get the flu shot every year. It's a safe, simple way to lower your risk of contracting the flu. (People with egg allergies should speak to their physician about certain considerations when getting the immunization.)

For people with diabetes, the CDC also recommends immunizing against pneumococcal disease because of their increased risk of the flu progressing to pneumonia. Talk to your doctor about whether this immunization is right for you.

If You Get Sick

It happens. The flu virus is an especially contagious disease, and it's possible you could become sick even after taking precautions.

The CDC encourages people with diabetes to seek medical care early. The sooner the flu is diagnosed, the sooner doctors can give antiviral medications. These medications work best if taken in the first 48 hours of having the flu, and they can make you feel better faster. Additionally, they can reduce the chances of flu-related complications, which is especially important for people with diabetes.

The American Diabetes Association (ADA) offers some advice on when to seek medical care to prevent serious complications. Seek care if you have:

• Vomiting or diarrhea for more than six hours.
• Fever or sickness for longer than two days without improvement.
• Glucose levels higher than 240 mg/dL despite administering sick-day insulin.
• Moderate to large ketones in the urine.
• Symptoms of ketoacidosis, such as fruity breath, difficulty breathing, dry mouth and skin, frequent urination and confusion.
• Symptoms of dehydration.

Creating a Sick-Day Plan

When you're sick, you should check your glucose levels more often and keep track of your numbers. The ADA suggests checking every four hours if you have type 1 and at least four times a day if you have type 2, but you should create your sick day plan with your care team.

Your sick-day plan may include recommendations on which medications to continue and at what dose and how many carbohydrates to consume throughout the day, in order to keep healthy glucose levels. It should also include strategies to increase fluids to prevent dehydration and flush out excess glucose and ketones if needed.

As well, don't forget that many cold and flu medications sold over-the-counter contain sugar, so check the labels or ask your pharmacist for sugar-free options.

If you don't have a sick-day plan in place, make an appointment to discuss it with your diabetes care team. A few moments of planning can make a world of difference when the flu comes knocking at your door.