Diabetic Ketoacidosis (DKA): Diagnosis and Management

Diabetic ketoacidosis (DKA) is a life-threatening emergency caused by a severe lack of insulin. Without insulin, the body breaks down fat for energy, producing ketones that make the blood acidic. DKA is most common in type 1 diabetes, and can be its first presentation, but it also occurs in type 2 diabetes.

Common triggers

• Infection (the most common trigger).
• Missed insulin doses or a pump failure.
• New diagnosis of type 1 diabetes.
• Myocardial infarction.
• Pancreatitis.
• Drugs, including SGLT2 inhibitors (which can cause DKA with near-normal glucose, called euglycaemic DKA) and corticosteroids.
• Pregnancy.

Clinical features

• Thirst, polyuria and dehydration.
• Nausea, vomiting and abdominal pain (which can mimic a surgical abdomen).
• Deep, rapid breathing (Kussmaul respiration).
• A fruity, "pear-drop" smell of ketones on the breath.
• Drowsiness, confusion and, in severe cases, coma.

Diagnosis (UK Joint British Diabetes Societies)

All three of the following:

• Ketonaemia 3.0 mmol/L or more, or significant ketonuria (2+ or more on urine dipstick).
• Blood glucose above 11.0 mmol/L, or known diabetes.
• Venous bicarbonate below 15.0 mmol/L and/or venous pH below 7.3.

Other investigations:

• urea and electrolytes, especially potassium
• full blood count
• blood cultures and a urine culture
• chest X-ray
• ECG
• tests for the trigger, for example troponin or a pregnancy test

Management principles

Follow your hospital's DKA protocol. The key elements are:

1. Fluids: IV 0.9% sodium chloride is the cornerstone. Give a bolus if the patient is shocked, then replace the deficit over the next 24–48 hours. Be more cautious in children, older adults, and patients with heart failure or kidney failure.
2. Insulin: a fixed-rate intravenous insulin infusion based on body weight (0.1 units/kg/hour in adults). Continue the patient's usual long-acting basal insulin.
3. Potassium: total body potassium is depleted even when the blood level looks normal or high, and insulin drives potassium into cells. Add potassium to the fluids according to the measured level, and monitor it frequently.
4. Glucose: when blood glucose falls below 14 mmol/L, add 10% glucose alongside the saline so insulin can continue until ketones clear.
5. Monitor hourly capillary glucose and ketones, plus venous pH, bicarbonate and potassium at regular intervals.
6. Treat the trigger, give thromboprophylaxis, and involve the diabetes team.

DKA has resolved when ketones are below 0.6 mmol/L and venous pH is above 7.3. Change to subcutaneous insulin when the patient is eating and drinking. Overlap the first subcutaneous dose with the infusion.

Complications

• Hypokalaemia and hyperkalaemia, leading to arrhythmias.
• Hypoglycaemia.
• Cerebral oedema, especially in children and young people. Watch for headache, falling consciousness or a slowing heart rate.
• Aspiration.
• Thrombosis.
• Acute kidney injury.

DKA versus HHS

The hyperosmolar hyperglycaemic state (HHS) is seen mostly in older people with type 2 diabetes. It features:

• very high glucose (often above 30 mmol/L)
• high serum osmolality (above 320 mOsm/kg)
• severe dehydration
• no significant ketoacidosis

It needs slower, careful correction.

Exam pearls

• Never stop basal insulin in DKA; continue it alongside the infusion.
• Abdominal pain and vomiting in a young person: always check glucose and ketones.
• Potassium is the electrolyte that kills. Check it before and during treatment.

See also Type 2 Diabetes, Acid–Base in 5 Steps and our Medicine Companion.

Test yourself

5 exam-style single-best-answer questions. Choose your answer, then tap “Show answer”.

1. Which set meets JBDS criteria for DKA?

   1. Ketones 2.0, glucose 9, pH 7.4
   2. Ketones 0.5, glucose 30, bicarbonate 22
   3. Ketones 0, glucose 40, osmolality 340
   4. Ketones 1.0, glucose 15, pH 7.35
   5. Ketones 3.5, glucose 20, pH 7.21
   Show answer

   Answer: E. Ketones 3.5, glucose 20, pH 7.21
   DKA: ketones ≥3.0, glucose >11 (or known diabetes), and pH <7.3 and/or bicarbonate <15.

2. Fixed-rate IV insulin rate in adult DKA:

   1. 1 unit/kg/h
   2. 0.1 units/kg/h
   3. 0.01 units/kg/h
   4. Sliding scale only
   5. 10 units/h for everyone
   Show answer

   Answer: B. 0.1 units/kg/h
   JBDS recommends a fixed-rate IV insulin infusion of 0.1 units/kg/hour.

3. When glucose falls below 14 mmol/L during DKA treatment, you should:

   1. Stop insulin
   2. Add 10% glucose and continue insulin
   3. Give bicarbonate
   4. Increase insulin rate
   5. Stop fluids
   Show answer

   Answer: B. Add 10% glucose and continue insulin
   Adding glucose allows insulin to continue until ketones clear without causing hypoglycaemia.

4. What should happen to the patient's long-acting basal insulin during DKA?

   1. Stop it
   2. Replace with metformin
   3. Double it
   4. Give it IV
   5. Continue it
   Show answer

   Answer: E. Continue it
   Continuing basal insulin prevents rebound ketosis when the infusion stops.

5. A child in DKA develops headache and falling consciousness. Concern?

   1. Cerebral oedema
   2. Hypocalcaemia
   3. Migraine
   4. Hypokalaemia
   5. Pancreatitis
   Show answer

   Answer: A. Cerebral oedema
   Cerebral oedema is a dangerous complication of DKA, especially in children and young people.

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Disclaimer

For education and exam preparation only. This is not medical advice and must not be used to diagnose or treat patients. Always follow current clinical guidelines and the advice of qualified senior colleagues.