DKA and Sick-Day Rules: The One Thing You Do Not Skip

Introduction

The sickest I have seen someone with type 1 get started with a vomiting bug and a completely reasonable decision. He could not keep food down, so he stopped his insulin, because in his head insulin was for food and there was no food. By the next morning he was breathing hard, his stomach hurt, and his partner said his breath smelled oddly sweet, like nail varnish. That is diabetic ketoacidosis, and it is the thing every sick-day rule is built to keep you away from. It is also almost entirely preventable once you understand why the instinct to stop insulin is exactly backwards.

What DKA actually is

When there is not enough insulin around, your cells cannot get at the sugar in your blood, so they do the same thing they would do in starvation. They start burning fat for fuel. The trouble is that burning fat produces acidic waste products called ketones, and in someone without working insulin they pile up faster than the body can clear them, and the blood itself turns acidic. That is what the word means, keto for the ketones, acidosis for the acid. Left to run it poisons the system, and it can be fatal. It is not a vague risk. It is the single most dangerous short-term thing that happens in type 1.

Why illness is the usual trigger

Here is the cruel twist that catches people out. When you are ill, fighting an infection, your body pumps out stress hormones that shove your blood sugar up and make your insulin work less well, so you actually need more insulin when you are sick, not less, even if you are barely eating. The bug does not care that you have skipped breakfast. So the day someone stops their insulin because they cannot face food is often the exact day their body needed extra, and that gap is where DKA gets its foothold. This is why the golden rule of being unwell with type 1 is short and absolute. You never stop your insulin.

The warning signs worth memorising

DKA gives you a window if you know what you are watching for, and it rarely arrives out of nowhere. Sugars that stay high and simply will not come down are usually the first clue, and the thirst and the peeing tend to ramp back up alongside them. Feeling sick is common, and for some people it tips into actual vomiting, or a stomach ache bad enough that families have ended up in a surgical assessment unit before anyone thought of diabetes. The breathing can turn deep and heavy as the body tries to blow off the acid building inside it, and there is a particular sweetish smell on the breath, a bit like nail varnish or pear drops, that a partner or a parent often notices before the person feeling it does. None of these on their own is an emergency. Several turning up together, alongside a high sugar and ketones, is.

What sick-day rules actually ask of you

The rules are less complicated than the fear around them. Keep taking your insulin, and be ready to take correction doses on top if your sugars are running high, guided by the plan your team gave you. Test more often than usual, roughly every two to four hours, right through the night if you are properly unwell. Check for ketones with a meter or urine strips once your sugar goes above about fourteen, because ketones are the early warning the acid is building. Keep sipping fluids so you do not dry out, and if you cannot eat, take your carbs as something drinkable that is not sugar-free. That is most of it.

When to stop managing at home

There is a line, and crossing it is not a failure, it is the plan working. If you are vomiting and cannot keep fluids down, if your ketones are high and climbing despite correction doses, if you are getting drowsy or confused or breathing hard, you stop trying to fix it at home and you get to an emergency department. DKA is treated well in hospital, with fluids and insulin through a drip, and people recover fully from it all the time. What turns it dangerous is leaving it too long out of fear or hope. Have your sick-day plan written down before you are ill, keep in-date ketone strips in the cupboard, and know who to phone out of hours.

Key points

• The golden rule when you are ill with type 1 is that you never stop your insulin, even if eating feels impossible. Illness usually means your body needs more of it, not less.
• DKA happens when a lack of insulin pushes the body to burn fat instead, and the ketones that leaves behind turn the blood acidic. It is a genuine emergency and it can be fatal if it runs too long.
• A sweetish, nail-varnish smell on the breath is one of the odder signs, and it is often a partner or a parent who smells it first, not the person themselves.
• On a sick day, keep the insulin going, test every couple of hours through the night if you need to, and start checking for ketones once your sugar climbs past about fourteen.
• If you cannot keep fluids down, or the ketones will not stop climbing, or you feel drowsy or confused, that is your cue to stop managing it at home and get to an emergency department.