Diabetes and illness: sick day care to keep blood sugar safe

Colds, flu, fevers and stomach upsets are part of life, but when you have diabetes they need extra care. This article explains why illness affects blood sugar and what a sensible "sick day" routine looks like. It draws on the US CDC, MedlinePlus and the NHS.

1. Introduction

The CDC says people with diabetes can get sick even when they try hard to prevent it, and that preparing ahead helps you know what to do ^[1]. MedlinePlus warns that delaying care when you are ill can make you much sicker, and with diabetes that delay can be life-threatening ^[2].

Why does illness matter? MedlinePlus explains that when you are sick, insulin works less well, so blood sugar can rise even if you take your usual medicines ^[2]. The NHS lists being unwell as a common trigger of high blood sugar ^[3]. MedlinePlus adds that feeling sick often makes you not want to eat or drink, which, surprisingly, can lead to a higher blood sugar ^[2].

2. Getting ready before you are ill

The CDC suggests keeping insulin, other diabetes medicines and easy-to-prepare foods at home so you have enough for several weeks ^[1]. Its list of useful items includes a thermometer, and foods and drinks that are easy on the stomach, such as soup, crackers, fruit juice, plain cooked cereal and unsweetened applesauce ^[1].

MedlinePlus advises talking with your provider about a sick day plan before you get ill, and making sure family members know the warning signs ^[2]. If you use insulin, it says to your provider should prescribe an emergency glucagon kit, and you should keep it available at all times ^[2]. Glucagon is a hormone medicine used in emergencies to raise blood sugar quickly. Ask your doctor whether you need one.

3. What to do on a sick day

Sources agree on these basic steps ^{[1, 2, 3]}:

• Check blood sugar more often. The CDC says to test every 4 hours and write down the results. MedlinePlus says every 2 to 4 hours, and sometimes hourly, and to record the time and any medicines taken. Your own plan may differ ^{[1, 2]}.
• Keep drinking. The CDC says to drink plenty of water to prevent dehydration ^[1]. MedlinePlus lists sugar-free choices such as water, clear broth and tomato juice, and says sugary drinks are acceptable if blood sugar is low or falling quickly ^[2].
• Try to eat as normal. MedlinePlus suggests small, frequent meals of easy foods such as bread, cooked cereal, rice or noodle soup and crackers, and the CDC suggests taking in some carbohydrate every 4 hours if you cannot eat meals ^{[1, 2]}.
• Keep taking your medicines. The CDC says to continue insulin and diabetes tablets as usual, even if your blood sugar is in range, because illness can change how much insulin you need ^[1]. MedlinePlus says not to skip or double doses unless your provider directs it ^[2]. The NHS gives the same message ^[3].
• Rest. MedlinePlus advises avoiding vigorous exercise while sick ^[2].
• Take your temperature. The CDC suggests checking morning and evening, since a fever may mean infection ^[1].

4. Ketones and diabetic ketoacidosis

Ketones are acids the body makes when it breaks down fat for fuel because there is not enough insulin. The CDC explains that too many ketones, produced too quickly, can cause diabetic ketoacidosis (DKA), a very serious condition that can lead to coma or death ^[1]. The NHS says a high ketone level is a sign of DKA and that your care team may ask you to test blood or urine ^[3].

The CDC suggests using an over-the-counter kit to test urine for ketones when you are sick, and says to call your doctor right away if ketones are present, because hospital treatment is probably needed ^[1]. MedlinePlus says people with type 1 diabetes whose blood sugar is high should check urine ketones each time they pass urine ^[2].

5. Special points

• Type 1 diabetes: MedlinePlus says to check urine ketones every time you pass urine when blood sugar is high ^[2].
• People who use insulin: the CDC and MedlinePlus say your insulin needs may change while you are sick, so follow the plan your team has given you and call your provider if you cannot eat your usual carbohydrates ^{[1, 2]}.
• Weight: the CDC suggests weighing yourself daily, because unplanned weight loss can be a sign of high blood sugar ^[1].

6. When to see a doctor

MedlinePlus lists reasons to contact your provider ^[2]:

• Blood sugar above 240 mg/dL (13.3 mmol/L) for more than a day
• Moderate or large ketones on urine tests
• Vomiting or diarrhoea for more than 4 hours
• Severe pain or chest pain
• A fever of 100 degrees Fahrenheit (37.7 degrees Celsius) or higher
• Confusion, vision, speech or balance problems, or trouble moving the arms or legs

The CDC says to go to the emergency room right away if you have trouble breathing, ketones in your urine, cannot keep liquids down for more than 4 hours, or have vomiting or severe diarrhoea lasting more than 6 hours ^[1]. It also lists a blood sugar below 60 mg/dL and a temperature over 101 degrees Fahrenheit for 24 hours ^[1]. If you are very tired or confused, ask someone else to call your doctor or take you to the emergency room ^[1].

In an emergency, call your local emergency number (112 in India, 911 in the United States).

7. Conclusion

Illness raises blood sugar and can lead to dehydration and ketoacidosis, so diabetes needs more attention when you are unwell. Prepare supplies, agree a written plan with your care team, check blood sugar and ketones as advised, keep drinking, and do not change medicines on your own. Phone your doctor early rather than late.