Diabetic ketoacidosis (DKA) is a life-threatening emergency that happens when the body has too little insulin. Without insulin, cells cannot use glucose, so the body burns fat and produces ketones, which make the blood acidic. It is most common in type 1 diabetes, and is often the way type 1 diabetes is first discovered in children and young adults, but it can also occur in type 2 diabetes. Good nursing care is the difference between a smooth recovery and a dangerous one.
Common triggers
- Infection (the most common trigger): chest, urine, skin, and in endemic areas, malaria.
- Missed insulin doses, including when insulin is unaffordable or unavailable.
- New, undiagnosed diabetes.
- Heart attack, stroke, pancreatitis, some medicines (including SGLT2 inhibitors, which can cause DKA with near-normal glucose).
Signs and symptoms
- Thirst, passing a lot of urine, weight loss, tiredness.
- Nausea, vomiting and abdominal pain (can mimic a surgical abdomen, especially in children).
- Deep, rapid breathing (Kussmaul breathing), as the body tries to blow off acid.
- A fruity, pear-drop smell on the breath (ketones).
- Dehydration: dry mouth, fast heart rate, low blood pressure.
- Drowsiness, confusion, and in severe cases, coma.
Diagnosis
The UK Joint British Diabetes Societies (JBDS) criteria require all three:
- Ketonaemia of 3.0 mmol/L or more (or significant ketonuria, 2+ or more on urine dipstick).
- 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.
US criteria (American Diabetes Association) are similar. Where blood ketone meters are not available, urine ketones and clinical assessment are used. See our guide to blood gas interpretation for reading the acidosis.
The three pillars of treatment
1. Fluids
Adults with DKA are often several litres dehydrated. Treatment usually starts with 0.9% sodium chloride, given quickly at first and then more slowly over the next 24–48 hours, as prescribed. In children, fluids are calculated carefully and given more slowly because of the risk of cerebral oedema. Use your paediatric DKA protocol (for example, the BSPED guideline in the UK or ISPAD internationally).
2. Insulin
Adults usually receive a fixed-rate intravenous insulin infusion (FRIII) of 0.1 units/kg/hour of soluble insulin, according to JBDS guidance. Continue the patient’s usual long-acting insulin if prescribed. Insulin is a high-risk drug: double-check the preparation (commonly 50 units in 50 mL, so 1 unit/mL), use a pump, and label the line.
When blood glucose falls below 14 mmol/L (about 250 mg/dL), 10% glucose is usually added alongside the saline, so insulin can continue clearing ketones without causing hypoglycaemia. Do not stop the insulin just because glucose is normal. The goal is to clear ketones.
3. Potassium
Total body potassium is low in DKA, even if the first blood result is normal or high. Insulin drives potassium back into cells, so levels can fall fast and cause dangerous heart rhythms. Potassium is usually added to fluids once the level is 5.5 mmol/L or below and the patient is passing urine, as prescribed. Use pre-mixed bags and a pump, and never give potassium as a bolus.
Hourly nursing checks
| Check | How often | Target or warning |
|---|---|---|
| Capillary blood glucose | Hourly | Fall of about 3 mmol/L per hour; avoid below 4 |
| Capillary blood ketones | Hourly | Fall of at least 0.5 mmol/L per hour |
| Vital signs, NEWS2, GCS | Hourly or more | Escalate falling GCS immediately |
| Fluid balance and urine output | Hourly | At least 0.5 mL/kg/hr |
| Venous gas: pH, bicarbonate, potassium | At 1 hour, 2 hours, then 2-hourly (or per protocol) | Potassium 4.0–5.5 mmol/L |
If ketones or glucose are not falling at the expected rate, check the pump, the line and the cannula before increasing insulin as prescribed.
Complications to watch for
- Hypoglycaemia and hypokalaemia: the most common treatment complications.
- Cerebral oedema (especially in children and young adults): headache, irritability, falling GCS, slowing heart rate, rising blood pressure. This is an emergency.
- Fluid overload in older or cardiac patients.
- Venous thrombosis: thromboprophylaxis as prescribed.
- Aspiration in drowsy, vomiting patients: consider a nasogastric tube.
Resolution and preventing the next episode
DKA is considered resolved when ketones are below 0.6 mmol/L and venous pH is above 7.3. The patient is moved back to subcutaneous insulin once eating and drinking, with an overlap so there is no gap in insulin cover. Before discharge, education matters as much as treatment:
- Sick-day rules: never stop insulin when unwell; check glucose and ketones more often; drink fluids; seek help early with vomiting.
- Insulin technique, storage (in hot climates, without a fridge, use cool clay pots or similar options advised locally) and injection site rotation.
- Understand why this episode happened, including whether cost or access to insulin is the problem, and link the patient with support.
Related: IV fluids guide · Insulin infusion calculations · Glasgow Coma Scale
Based on Joint British Diabetes Societies guidance on DKA in adults, ISPAD guidance for children, and American Diabetes Association consensus. Educational content: follow your local DKA protocol.