Whether your head feels like it's stuffed with cotton because you have a cold or you're spending a lot of time on the toilet because of a stomach bug, being sick is no fun for anyone.

For people with diabetes, being sick can also affect blood sugar levels. The good news is that taking a few extra precautions can help you keep your blood sugar levels under control.

How Illness Affects Blood Sugar Levels

When you get sick — whether it's a minor illness like a sore throat or cold or a bigger problem like dehydration or surgery — the body perceives the illness as stress. To relieve the stress, the body fights the illness. This process requires more energy than the body normally uses.

On one hand, this is good because it helps supply the extra fuel the body needs. On the other hand, in a person with diabetes, this can lead to high blood sugar levels. Some illnesses cause the opposite problem, though. If you don't feel like eating or have nausea or vomiting, and you're taking the same amount of insulin you normally do, you can develop blood sugar levels that are too low.

Blood sugar levels can be very unpredictable when you're sick. Because you can't be sure how the illness will affect your blood sugar levels, it's important to check blood sugar levels often on sick days and adjust your insulin doses as needed.

Planning for Sick Days

Your diabetes management plan will help you know what to do when you're sick. The plan might tell you:

• how to monitor your blood glucose levels and ketones when you're sick
• which medicines are OK to take
• what changes you might make to your food and drink and diabetes medications
• when to call your doctor

In addition, people with diabetes should get the pneumococcal vaccine, which protects against some serious infections. You should also get a flu shot every year. These vaccines may help you keep your diabetes under better control and cut down on the number of sick days you have.

What to Do When You're Sick

Your doctor will give you specific advice when you're sick. But here are some general guidelines:

• Stay on track. Unless your doctor tells you to make a change, keep taking the same diabetes medications. You need to keep taking insulin when you're sick, even if you're not eating as much as you usually do. That's because your liver makes and releases glucose into your blood — even when you're stuck channel surfing on the couch — so you always need insulin. Some people with diabetes need more insulin than usual on sick days. Even some people with type 2 diabetes who don't usually take insulin may need some on sick days.
• Check blood sugar and ketone levels often. Your doctor will tell you how often to check your blood sugar and ketone levels — usually you'll need to check more frequently while you're sick.
• Pay special attention to nausea and vomiting. People with diabetes sometimes catch a bug that causes nausea or vomiting. But nausea and vomiting are also symptoms of ketoacidosis. If you feel sick to your stomach or are throwing up, it's important to keep a close eye on your blood glucose and ketone levels and seek medical help according to the guidelines in your diabetes management plan. The best approach is to stick to your insulin schedule, check ketones regularly, and follow your doctor's advice about when to get help.
• Prevent dehydration. Be sure to drink plenty of fluids, even if you have nausea or vomiting. Your doctor can recommend the types and amounts of fluids to drink that can help you manage both your illness and your blood sugar levels.
• Use over-the-counter (OTC) medications wisely. People sometimes take OTC medications for illnesses like the cold or flu. But these have ingredients that can raise or lower blood sugar or cause symptoms that look similar to high or low blood sugar. Follow your doctor's advice about taking an OTC medication. Your doctor might even include common medications that are OK for you in your diabetes management plan, and can also explain the things to check for on medication labels.
• Take notes. Your doctor might have a lot of questions about your illness and the symptoms you've had. You can answer these questions more easily if you write down your symptoms, medications and doses, what food and drink you had, and whether you kept the food down. Also, tell the doctor if you've lost weight or had a fever and have the record of your blood sugar and ketone level test results handy.
• Get some rest. People need rest when they're sick. It helps your body focus its energy on fighting illness. If you think you need to, let a parent take over managing your diabetes for a day or two. Your mom or dad can keep track of your blood sugar levels and figure out the best insulin dosage — and you can get some sleep!

When to Call Your Doctor

Your diabetes management plan will explain when you may need medical help. It will tell you what to do and whom to call. Here are some general reasons for calling the doctor:

• all the same reasons you normally would call about diabetes management, as well as for any questions you have about being sick
• if you have no appetite or you can't eat or drink
• if your blood sugar level is low because you haven't been eating much — but remember to take steps at home to bring your blood sugar back up
• if you keep vomiting or having diarrhea
• if your blood sugar levels are high for several checks or don't decrease when you take extra insulin
• if you have moderate or large amounts of ketones in the urine
• if you think you might have ketoacidosis
• if you can't eat or drink because you're having a medical test like an X-ray, surgery, or a dental procedure

Any time you have questions or concerns, ask your doctor for advice.

Reviewed by: Steven Dowshen, MD
Date reviewed: August 2010