Sick days with an insulin pump

Being ill changes how diabetes behaves, whatever the treatment. For someone on a pump there is one extra layer: the insulin supply depends on a device, a cannula and a set that can fail while the person is already unwell. This page summarises published guidance so the ideas are familiar before they are needed. It is not a plan for any individual: each person should follow the sick day plan from their own diabetes team, and call the team when unsure.

Why illness changes glucose

Diabetes UK explains that illness, infection and other forms of stress can raise blood glucose to dangerously high levels. The body releases more glucose into the bloodstream, even when the person is eating less than usual, and people with diabetes cannot make extra insulin to cope. In the other direction, being sick or having diarrhoea can make glucose drop because less food is eaten or absorbed. These effects are why sick day rules exist.

The general rules

Diabetes UK sets out its version of the rules for anyone with diabetes. They include contacting the diabetes team rather than panicking, and keeping up diabetes medication even if the person does not feel like eating. Insulin may need to be increased or sometimes decreased, and the team should advise how. Glucose should be checked more often, at least every four hours or as the healthcare team advises, including during the night. It advises unsweetened drinks, little-and-often eating to keep carbohydrate up, and urgent medical help if fluids cannot be kept down.

The NHS puts the central point plainly in its list of things not to do: do not stop taking insulin, even when not eating, and do not skip doses.

Ketones and what the NHS says about levels

Diabetes UK advises that people with type 1 diabetes check ketone levels if glucose is above target, which it says is usually above 14 mmol/L, and as their healthcare team advises. It adds that if someone is sick they should test for ketones whatever the glucose reading, and contact the team if ketones are found. Teams differ on the trigger: DAFNE's pump sick day guidance, written for people who have completed its course, uses more than 13.0 mmol/L.

The NHS gives these ketone levels for a blood ketone meter, and stresses they are a guide because the diabetes care team will say what levels to look for:

• under 0.6 mmol/L is normal
• 0.6 to 1.5 mmol/L is slightly high, so test again in 2 hours
• 1.6 to 3 mmol/L means a risk of DKA, so speak to the diabetes care team for advice
• over 3 mmol/L is high and may mean DKA, so call 999 or go to A&E

For urine strips, the NHS says over 2+ is high and may mean DKA. See diabetic ketoacidosis in the glossary.

What is different with a pump

Diabetes UK says an insulin pump uses fast-acting insulin only, and that DKA can develop very quickly if there is a problem with the pump delivering it. A set that is blocked or has come unattached can be the cause. Unexplained high glucose can also come from the cannula or a failed pump. The alarms and fail-safes page covers the warning signals.

Two documents opened for this page show how pump teams respond. DAFNE's pump sick day guidance says that when significant ketones are present, the person should change the cannula, infusion set and insulin reservoir, use a pen for correction insulin, and that a pump must never be suspended or stopped. An NHS England London crib sheet for people on pumps, published in 2020 during the coronavirus pandemic, says to give a correction with a pen if glucose has not changed after two hours, to change the set and reservoir, and not to go to sleep with unexplained high glucose that has not resolved or within two hours of a new set change. Both documents give extra insulin as percentages of total daily dose. Those figures are deliberately not repeated here: they belong to individual plans agreed with a team. The glossary defines cannula and infusion set; infusion sets and site rotation covers set changes.

DKA warning signs

The NHS lists these symptoms of diabetic ketoacidosis: feeling thirsty, needing to pee more often, stomach pain, feeling or being sick, diarrhoea, breathing more deeply than usual, breath that smells fruity (like pear drops or nail polish remover), feeling tired, sleepy or confused, and blurred vision. They usually develop over 24 hours but can be faster.

The NHS says to call 999 or go to A&E for ketones over 3 mmol/L in blood or over 2+ in urine, or for DKA symptoms when ketone levels are unknown, and not to drive oneself. It says to call the diabetes care team now or use NHS 111 if glucose is high and insulin is not bringing it down even with normal ketones, if ketones are slightly high and the person feels unwell, or if ketones are 1.6 to 3 mmol/L even without feeling unwell. The NHS England crib sheet adds that face-to-face care is needed after continuous vomiting for more than four to six hours or if ketones are not reducing, and the DAFNE guidance says to go to hospital as an emergency when someone vomits, cannot keep fluids down or cannot control glucose or ketones.

Getting ready before illness

Diabetes UK suggests asking the team about an individual care plan for sick days. The NHS says to follow the sick day rules given by the care team, and notes that ketone testing kit can be obtained free from the NHS or bought from a pharmacy. The NHS England crib sheet lists alternative insulin delivery, a glucose meter with strips and unexpired ketone strips as things to have to hand at all times. Back-up pens are discussed further in alarms, occlusions and fail-safes, and the official guidance page lists where to find current UK documents.

In short

Illness raises glucose and ketones can follow, and with a pump the possibility of a delivery failure sits on top of that. The common messages from Diabetes UK, the NHS and pump teams are to keep taking insulin, check glucose and ketones more often, drink fluids, and call the diabetes team, NHS 111 or 999 at the points the NHS describes. The figures in any leaflet are a guide; the person's own sick day plan has the final word.