Why can an insulin pump cause DKA quickly?

Because it delivers only rapid-acting insulin with no long-acting reserve. If delivery stops (blockage, dislodged site, empty reservoir, fault), working insulin falls within hours, the body makes ketones, and glucose and ketones rise fast toward DKA, faster than on injections.

What should I do if my glucose is unexpectedly high?

Suspect the pump or site. Give the correction by pen (not the possibly-failed pump), change the whole infusion set and reservoir, check for ketones, drink fluids, and recheck after a short interval. Seek urgent help if ketones rise or you feel unwell.

Should I stop my insulin if I am ill and not eating?

No — never stop your background insulin when ill, even if eating less or vomiting. Illness usually raises insulin needs, and stopping can trigger DKA. Follow your written sick-day plan for extra correction, keep hydrated, and seek help if you cannot keep fluids down.

Sick-Day Rules & Preventing DKA with an Insulin Pump

Q: When should I check for ketones?

Whenever your glucose is unexpectedly high, or whenever you feel unwell or are vomiting, even if glucose is not very high. Illness-related DKA can occur with near-normal glucose, a higher risk with SGLT2 inhibitor tablets. If ketones are present, act on your plan and contact your team.

Q: What are the signs of DKA?

High glucose with ketones, nausea and vomiting, tummy pain, excessive thirst and urination, deep or rapid breathing, breath smelling fruity or like pear drops, and drowsiness or confusion. This is an emergency — call 995 or go to A&E without delay.

Written & reviewed by the BestDoctors.sg editorial team · Last updated 28 Aug 2026 · General information, not medical advice

Of everything a pump user needs to know, sick-day rules and preventing diabetic ketoacidosis (DKA) matter most. Because a pump uses only rapid-acting insulin, problems can escalate faster than on injections, so knowing the rules in advance, and having your kit ready, can be lifesaving. This guide sets out the core danger, the backup you always need, and the warning signs that mean an emergency.

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In a medical emergency, or for severe or sudden symptoms such as breathing difficulty, chest pain, fainting or stroke signs, call 995 immediately.

This is general information and does not replace your diabetes team’s sick-day plan. Never stop your background insulin when ill. Call 995 for signs of DKA: high glucose with ketones, vomiting, tummy pain, deep or rapid breathing, fruity-smelling breath, or drowsiness and confusion.

The core danger

An insulin pump delivers only rapid-acting insulin as a steady background, with no long-acting insulin stored in the body. So if delivery stops for any reason, a blocked or kinked cannula, a dislodged or leaking site, an empty reservoir, air in the tubing or a pump fault, your working insulin falls within hours. When the body lacks insulin it starts making ketones, and glucose and ketones can rise fast toward DKA, faster than for someone on long-acting injections. This is the reason all the rules below exist.

Always keep backup pens

Never be without backup insulin, and know how to use it. Keep insulin pens or syringes with both rapid-acting and long-acting insulin, and agree with your team in advance how to switch to injections if the pump fails. A simple emergency kit, with spare insulin, spare infusion sets and a reservoir, ketone testing supplies, a glucose meter, fast-acting glucose, a power source, and a written note of your pump settings, means a pump problem is an inconvenience rather than a crisis.

Checking ketones

Ketones are the early warning that the body is short of insulin, so check them, by blood or urine, whenever your glucose is unexpectedly high, or whenever you feel unwell or are vomiting, even if your glucose is not very high. Illness-related DKA can occur with near-normal glucose, a risk that is higher for people taking certain tablets called SGLT2 inhibitors. If ketones are present, act on your sick-day plan and contact your team; rising ketones are a signal not to wait.

Unexplained highs: suspect the pump

If your glucose is unexpectedly high and will not come down, do not simply keep correcting with the pump, because the pump or site may be the problem. Give the correction dose by pen instead, then check and change the whole infusion set, cannula and reservoir, check for ketones, drink fluids, and recheck your glucose and ketones after a short interval. Treating an unexplained high as a possible delivery failure, and correcting by pen, is one of the most important habits a pump user can build.

When ill, keep taking insulin

The golden rule of sick days is never to stop your background insulin, even if you are eating less or being sick. Illness usually raises your insulin needs, not lowers them, so stopping insulin is exactly the wrong move and can trigger DKA. Follow your written sick-day plan for any extra correction doses, keep sipping fluids to stay hydrated, and rest. If you cannot keep fluids down, that is a reason to seek urgent help.

Monitor more closely

When you are unwell, check your glucose and ketones more often than usual, including through the night if your team advises, so a rising trend is caught early. Have your written, personalised sick-day plan agreed with your team before you ever need it, covering when and how much extra insulin to give and when to call for help. Preparation is what keeps a common illness from becoming an emergency. It helps to keep your sick-day kit somewhere easy to grab, and to make sure a family member or housemate knows where it is and how to help, so you are not hunting for supplies when you feel awful.

Signs of DKA and when to get help

DKA is a medical emergency, and the signs are worth knowing by heart: high glucose with ketones, nausea and vomiting, tummy pain, excessive thirst and passing lots of urine, deep or rapid breathing, breath smelling fruity or like pear drops, and drowsiness or confusion. If you notice these, call 995 or go to A&E without delay. Also seek urgent help if you are vomiting and cannot keep fluids down, if moderate or high ketones are not coming down despite correction and fluids, or if you become drowsy or short of breath. Acting early and calmly on the rules set out in this guide is what keeps the large majority of pump problems minor and manageable. In Singapore, keep your team’s number and your emergency kit ready, and 995 is for these situations.

Sources

Diabetes UK — Diabetic ketoacidosis (DKA): diabetes.org.uk
Diabetes UK — Diabetes and being ill (sick-day rules): diabetes.org.uk
NHS — Diabetic ketoacidosis: nhs.uk
UCLH NHS — High glucose and ketones with insulin pumps: uclh.nhs.uk

General information only. This guide supports, but does not replace, the advice of your diabetes team (your endocrinologist and diabetes nurse educator), who set your insulin and settings and train you on your devices. Never make big changes to your settings alone, and always keep backup insulin pens and ketone testing. An insulin pump uses only rapid-acting insulin, so if delivery stops, glucose and ketones can rise fast: unexplained high glucose means check the site, change the set and give insulin by pen. Call 995 for signs of diabetic ketoacidosis (high glucose with ketones, vomiting, tummy pain, deep or rapid breathing, drowsiness) or for a severe hypo (unable to treat yourself, fitting or unconscious). If you are struggling emotionally, you are not alone: the Samaritans of Singapore (SOS) are on 1767 and mindline.sg on 1771.

Sick-Day Rules & Preventing DKA with a Pump (Singapore)