DKA vs HHNS

Both are extreme hyperglycemia

DKA and HHNS are both forms of extreme hyperglycemia, and most of the picture is the same in both: extremely high blood sugar, an altered mental status, and warm, red, dry skin.

Both bring the three Ps. Polyuria is excessive urination. Polydipsia is excessive thirst, from the dehydration all that urination causes. Polyphagia is excessive hunger: the cells are not getting the glucose, so they keep sending hunger signals.

There are just three major differences: who gets it, the fruity breath, and how fast and how high the sugar climbs.

Start with insulin

Insulin takes glucose out of the bloodstream and pushes it into the cells, where the cells use it to make energy. With insulin working, blood sugar stays normal.

In type 1, the immune system destroys the cells in the pancreas that make insulin. With no insulin, glucose cannot get into the cells. In type 2, the pancreas still produces insulin, but the cells do not respond to it well. At first the pancreas just makes more, but eventually even that is not enough to keep glucose levels normal. Either way, glucose builds up in the blood.

Difference 1: who gets it

Only type 2 diabetics will have HHNS. If a type 1 diabetic's sugar is high and they are altered, that will always be DKA.

The memory tool is one is none: type 1 diabetics have no insulin production. A type 2 diabetic's pancreas still produces insulin. Their cells are just resistant to it.

DKA is almost always a type 1 diabetic. A very severe type 2 diabetic can go into DKA, but it is rare.

Difference 2: the fruity breath

DKA brings fruity acetone breath, plus Kussmaul respirations: deep and rapid breathing, trying to breathe off that acidity. You will never get the fruity breath from HHNS. That only ever happens with DKA.

Think of a keto diet. A keto diet is low carb and low sugar, so the body burns fat instead of sugar, and burning fat makes ketones. In DKA there is no insulin, so the cells get no glucose at all. The body burns only fat, which makes the ketones and the fruity breath.

In HHNS there is still enough insulin for the cells to metabolize glucose, just not well enough to keep glucose levels normal. The body is not burning only fat, so there are no ketones.

Difference 3: how fast and how high

DKA develops over a couple of hours to a couple of days, and symptoms start at a glucose level around 300 to 350. HHNS develops over several days to several weeks, and symptoms start around 600 to 650.

In type 2, the pancreas still produces insulin, so the sugar climbs a lot slower and the body can compensate longer before symptoms show.

Practice: DKA or HHNS?

A patient is found confused at home. They have type 2 diabetes and a week of heavy thirst and constant trips to the bathroom. The skin is warm and dry, with no odor on the breath, and the glucometer reads HI, too high to measure.

It is HHNS, by all three differences. They are a type 2 diabetic, and only type 2 diabetics will have HHNS. There is no fruity breath, which only ever happens with DKA. The onset was slow: the symptoms built up over a week, and HHNS takes several days to several weeks to develop.

Common questions

What are the three differences between DKA and HHNS?

Who gets it: DKA is almost always a type 1 diabetic, and only type 2 diabetics will have HHNS. The breath: only DKA brings fruity acetone breath and Kussmaul respirations. How fast and how high: DKA develops over a couple of hours to a couple of days with symptoms around 300 to 350, and HHNS takes several days to several weeks with symptoms around 600 to 650.

Can a type 1 diabetic get HHNS?

No. Only type 2 diabetics will have HHNS. If a type 1 diabetic's sugar is high and they are altered, that will always be DKA. The memory tool is one is none: type 1 diabetics have no insulin production.

Why does HHNS not cause fruity breath?

Fruity breath comes from ketones, and ketones come from burning fat. In DKA there is no insulin, so the body burns only fat. In HHNS the pancreas still produces insulin, enough for the cells to keep metabolizing glucose, so the body does not make those ketones.

At what blood sugar do DKA and HHNS symptoms start?

DKA symptoms usually start around 300 to 350. HHNS symptoms usually start around 600 to 650, because the sugar climbs a lot slower and the body can compensate longer before symptoms show.

What do DKA and HHNS have in common?

Both are extreme hyperglycemia: extremely high blood sugar, an altered mental status, warm, red, dry skin, and the three Ps of excessive urination, thirst, and hunger.

Can I print this DKA vs HHNS chart or use it in class?

Yes. The chart is free to view, download, print, and share with your class or study group. A link back to nremttutoring.com is appreciated but not required.