Diabetic ketoacidosis (DKA) happens when the body has too little insulin. Without insulin, cells cannot use glucose, so the body breaks down fat for energy, producing ketones that make the blood acidic. It is most common in type 1 diabetes but can occur in type 2, and it is a medical emergency.
Diagnosis: all three must be present
| Criterion | Threshold |
|---|---|
| Ketones | Blood ketones 3.0 mmol/L or more, or urine ketones 2+ or more |
| Glucose | Blood glucose above 11.0 mmol/L (about 200 mg/dL), or known diabetes |
| Acidosis | Venous bicarbonate below 15.0 mmol/L and/or venous pH below 7.3 |
Watch for euglycaemic DKA: people taking SGLT2 inhibitors (such as dapagliflozin or empagliflozin) can develop DKA with near-normal glucose levels. Always check ketones if they are unwell.
Common triggers
- Infection
- Missed insulin doses, or an insulin pump failure
- New diagnosis of type 1 diabetes
- Heart attack, pancreatitis, surgery or alcohol excess
Signs and symptoms
- Thirst, passing a lot of urine, weight loss
- Nausea, vomiting and abdominal pain
- Deep, rapid breathing (Kussmaul breathing) and a fruity smell on the breath
- Dehydration, tachycardia, low blood pressure
- Drowsiness or confusion
Treatment in adults: the main elements
1. Fluids
Fluid replacement with 0.9% sodium chloride comes first. If systolic BP is below 90 mmHg, a 500 mL bolus is given over 10–15 minutes and repeated as needed. Otherwise a typical regimen is 1 litre over the first hour, then progressively slower bags over the following hours, as prescribed. Older adults and people with heart or kidney failure need closer review for fluid overload.
2. Fixed-rate IV insulin infusion
Soluble insulin is given at 0.1 units/kg/hour based on estimated weight. Continue the patient’s usual long-acting basal insulin, which helps prevent rebound ketosis when the infusion stops.
3. Glucose
When blood glucose falls below 14 mmol/L, add 10% glucose alongside the saline, as prescribed, so insulin can continue clearing ketones without causing hypoglycaemia.
4. Potassium
| Potassium in the first 24 hours | Replacement per litre of fluid |
|---|---|
| Above 5.5 mmol/L | None |
| 3.5–5.5 mmol/L | 40 mmol/L |
| Below 3.5 mmol/L | Senior review; extra potassium needed, often via a central line in high dependency care |
Nursing monitoring
- Hourly capillary glucose and blood ketones
- Venous blood gas for pH, bicarbonate and potassium at 60 minutes, 2 hours, then every 2 hours
- Hourly observations, NEWS2 and a strict fluid balance chart; consider a urinary catheter
- Neurological observations: headache, new confusion or a falling level of consciousness need urgent review
- ECG monitoring if potassium is abnormal
| Target rate of improvement | Per hour |
|---|---|
| Blood ketones | Fall of at least 0.5 mmol/L |
| Venous bicarbonate | Rise of at least 3.0 mmol/L |
| Blood glucose | Fall of at least 3.0 mmol/L |
When DKA has resolved
DKA is resolved when blood ketones are below 0.6 mmol/L and venous pH is above 7.3. The patient should then restart subcutaneous insulin with a meal, and the IV insulin should continue for 30–60 minutes after the first subcutaneous rapid-acting dose before it is stopped.
Before discharge
- Find and treat the cause
- Specialist diabetes team review
- Teach sick-day rules: never stop basal insulin, check ketones when unwell, drink fluids, seek help early
- Check the patient can use their meter, ketone strips and insulin pens correctly
Children and young people have separate DKA protocols with more cautious fluids, because of the risk of cerebral oedema.
Related: Hyperosmolar hyperglycaemic state (HHS) · Hypoglycaemia treatment
Source: Joint British Diabetes Societies for Inpatient Care, The management of diabetic ketoacidosis in adults (2023 update). Follow your local protocol and prescriber’s instructions.
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