DKA and HHS
Fluids first, check the potassium, then fixed-rate IV insulin by weight. Keep the insulin running and always find out why it happened.
A 19-year-old with type 1 diabetes has been vomiting since yesterday and stopped his insulin because he "wasn't eating". He is breathing deeply and fast. Sugar 486 mg/dL (27 mmol/L), ketones 5.8 mmol/L, pH 7.08, potassium 5.1 mmol/L.
What do you do in the first hour?
- ABCDE and two cannulasLarge cannulas. Check GCS and BP.
- Bloods and a venous gasCapillary sugar and ketones, venous pH, bicarbonate and potassium, urea and creatinine, CBC, CRP, cultures if febrile.
- Start fluids0.9% sodium chloride. If systolic BP is below 90: 500 mL over 10–15 minutes, repeat. Otherwise 1 litre over 1 hour.
- Check the potassium before insulinIf potassium is below 3.5 mmol/L, call your senior: potassium first, insulin may need to wait.
- Start fixed-rate IV insulin0.1 units/kg/hour of actual body weight. No bolus.
- Continue the usual long-acting insulinGlargine, detemir or NPH at the normal time. This prevents rebound DKA.
- Find the triggerMissed insulin, infection, new diabetes, heart attack, pancreatitis, SGLT2 tablets.
- Hourly sugar and ketonesVenous gas at 1, 2 and 4 hours, then 4-hourly.
- pH below 7.0 or bicarbonate below 5
- Ketones above 6 mmol/L
- Potassium below 3.5 at any time
- GCS below 12 or falling
- Systolic BP below 90 after fluids
- Headache, slow pulse or confusion during treatment
- Pregnant
- Not improving after 2–3 hours
- Low potassium during treatment
- Low sugar during treatment
- Cerebral oedema in young patients
- Euglycaemic DKA on SGLT2 tablets
- The trigger: sepsis, heart attack, pancreatitis
- HHS treated as fast as DKA
| Diagnosis | Ketones 3 mmol/L or more, sugar above 200 mg/dL (11 mmol/L) or known diabetes, and bicarbonate below 15 or pH below 7.3 |
| Insulin | Fixed rate 0.1 units/kg/hour, started once potassium is known to be 3.5 or more |
| Potassium per litre | Above 5.5: none. 3.5–5.5: 40 mmol. Below 3.5: senior now |
| Add dextrose | When sugar falls below 250 mg/dL (14 mmol/L): 10% dextrose 125 mL/hour, keep insulin running |
| Targets each hour | Ketones fall 0.5 mmol/L or more. Sugar falls about 54 mg/dL (3 mmol/L) |
| Resolved | Ketones below 0.6 mmol/L and pH above 7.3 |
Check every dose against a current drug reference and your hospital protocol.
On this page
What DKA is
DKA happens when there is not enough insulin. Without insulin, cells cannot use sugar, so the body breaks down fat for energy and makes ketones, which are acids. The sugar rises, spills into the urine and drags water with it, so the patient becomes very dry. The acid makes them breathe deeply and fast to blow off carbon dioxide (Kussmaul breathing).
- It is usually type 1 diabetes, often the first presentation in a child or young adult, but it can happen in type 2.
- Common triggers in Pakistan: missed insulin (cost, fasting, "the sugar was normal so I stopped"), infections, and new undiagnosed diabetes.
- What kills in DKA: potassium that is too low or too high, cerebral oedema, and the underlying cause.
- Usually type 1, younger
- Develops over hours to a day
- Ketones 3 mmol/L or more and acidosis
- Sugar often 250–600 mg/dL (14–33 mmol/L)
- Usually older type 2
- Develops over days
- Very high sugar, often above 540 mg/dL (30 mmol/L)
- Osmolality 320 or more, little or no ketosis
- Needs slower correction
Recognising DKA
- Thirst, passing lots of urine, weight loss and tiredness over a few days.
- Vomiting and belly pain (can look like a surgical abdomen).
- Deep, sighing breathing and a sweet "pear drop" smell on the breath.
- Dry mouth, fast pulse, low BP, drowsiness.
- Ketones: blood ketones 3 mmol/L or more (or urine ketones 2+ or more).
- Sugar: above 200 mg/dL (11 mmol/L), or known diabetes.
- Acid: venous bicarbonate below 15 mmol/L and/or venous pH below 7.3.
On SGLT2 tablets (empagliflozin, dapagliflozin) the sugar can be near normal. Check ketones in any unwell diabetic on these tablets.
Any one of: ketones above 6 mmol/L, bicarbonate below 5, pH below 7.0, potassium below 3.5 on arrival, GCS below 12, SpO₂ below 92% on air, systolic BP below 90, pulse above 100 or below 60, anion gap above 16.
History and examination
- Known diabetes? Which insulin, how much, and when was the last dose?
- Why did it happen: vomiting, infection, chest pain, belly pain, fasting, insulin not available.
- Medicines: SGLT2 tablets, steroids.
- Pregnancy in women of child-bearing age.
- Examine: GCS, pulse, BP, breathing pattern, dryness, and look for the source of infection (chest, urine, skin, feet).
- Belly pain is common in DKA itself and settles as ketones clear. If it does not settle, look for a surgical cause such as pancreatitis or appendicitis.
Investigations
| Test | Why |
|---|---|
| Capillary sugar and blood ketones | Diagnosis, then hourly |
| Venous gas | pH, bicarbonate and potassium at 1, 2 and 4 hours, then every 4 hours (more often if potassium is abnormal) |
| Urea, creatinine, electrolytes | Kidney injury, sodium, potassium. Potassium in mmol/L is the same as mEq/L |
| CBC, CRP, cultures, urine, chest X-ray | Find the infection. The white count rises in DKA alone, so look for a real source |
| ECG | Potassium effects (peaked or flat T waves), heart attack as the trigger |
| Lipase | Pancreatitis. Amylase can rise in DKA alone |
| Serum osmolality | For HHS: 2 × sodium + glucose (mmol/L) + urea (mmol/L) |
| Pregnancy test | Women of child-bearing age |
Fluids
- 0 h1 litre over 1 hour
- 1 h1 litre over 2 hours
- 3 h1 litre over 2 hours
- 5 h1 litre over 4 hours
- 9 h1 litre over 4 hours
- 13 h1 litre over 6 hours
Potassium
Insulin drives potassium into cells. A patient who arrives with normal or high potassium can drop dangerously low within a few hours of starting insulin. Low potassium causes arrhythmias and cardiac arrest.
- No potassium
- Recheck in 1–2 hours
40 mmol potassium chloride in each litre
- Senior review now
- More potassium, usually through a central line or in HDU
- Insulin may need to wait
Never give potassium as an IV push. It causes cardiac arrest. Potassium always goes into a bag of fluid, mixed well, on a pump.
Insulin
Never stop the insulin because the sugar has come down. Add 10% dextrose instead. It is the insulin that clears the ketones, not the fluids.
- SugarShould fall by about 54 mg/dL (3 mmol/L) per hour. Below 250 mg/dL (14 mmol/L): add 10% dextrose.
- KetonesShould fall by at least 0.5 mmol/L per hour (or bicarbonate rise by 3 mmol/L per hour).
- PotassiumKeep 4–5.5 mmol/L. Adjust the potassium in the next bag.
- If ketones are not fallingCheck the pump, the line and the cannula first. Then increase insulin by 1 unit/hour.
- Fluid balance and GCSUrine output, chest, and any headache or confusion.
Getting off the drip
- Ketones are below 0.6 mmol/L and
- Venous pH is above 7.3.
Then: the patient eats a meal, gives their usual rapid-acting insulin injection with it, and the IV insulin stops 30–60 minutes after that injection. Stopping the drip without an injection first brings the DKA back.
HHS
- Fluids are the main treatment. 0.9% sodium chloride, 1 L over 1 hour, then guided by response. Often 3–6 litres in the first 12 hours.
- Insulin only if the sugar stops falling with fluids alone, or if ketones are 1 mmol/L or more: 0.05 units/kg/hour (half the DKA rate).
- Correct slowly: sugar should fall no faster than 90 mg/dL (5 mmol/L) per hour, and sodium should change no more than 10 mmol/L in 24 hours.
- High clot risk: prophylactic enoxaparin unless contraindicated.
- Feet: check and protect the heels. Pressure ulcers develop fast in dry, drowsy older patients.
Complications to watch for
Mostly children and young adults, usually a few hours into treatment. Headache, confusion, irritability, slow pulse, rising BP, falling GCS. Call your senior and ICU now. Mannitol or hypertonic saline is given straight away. Do not wait for a CT.
- Low potassium: check at 1 and 2 hours, then at least every 2 hours while it is abnormal.
- Low sugar: hourly checks, dextrose once below 250 mg/dL.
- Fluid overload: in the elderly and in heart or kidney failure. Listen to the chest.
- Clots: prophylactic enoxaparin for most adults.
Before discharge
- Diabetes team or senior review: why did it happen?
- Sick-day rules: never stop the long-acting insulin, even when not eating. Check sugar and ketones every 2–4 hours when unwell. Seek help early if vomiting.
- Check injection technique and that insulin can be obtained and stored properly.
- Ramadan: people with type 1 diabetes who wish to fast need individual advice from their diabetes team before Ramadan.
- Follow-up in diabetes clinic.
Common mistakes
- Starting insulin before knowing the potassium.
- Stopping the insulin when the sugar falls, instead of adding dextrose.
- Stopping the IV insulin without giving a subcutaneous dose first.
- Forgetting the patient's usual long-acting insulin.
- Missing euglycaemic DKA because the sugar looked "only" mildly raised.
- Correcting HHS as fast as DKA.
Frequently asked questions
What is the insulin dose in DKA?
A fixed-rate IV infusion of soluble insulin at 0.1 units/kg/hour based on actual body weight, with the usual long-acting insulin continued.
When should potassium be added in DKA?
From the second bag of fluid: none if potassium is above 5.5, 40 mmol per litre if it is 3.5–5.5, and senior review with more potassium if it is below 3.5.
When is dextrose added in DKA?
When blood sugar falls below 250 mg/dL (14 mmol/L), add 10% dextrose at 125 mL/hour alongside the saline and keep the insulin running.
When has DKA resolved?
When blood ketones are below 0.6 mmol/L and venous pH is above 7.3. Then switch to subcutaneous insulin with a meal.
How is DKA different from HHS?
DKA has high ketones and acidosis, usually in type 1 diabetes, and develops over hours. HHS has very high sugar and osmolality with little ketosis, usually in older type 2 patients, develops over days, and needs slower correction.
Test yourself
Exam-style questions on this guide, from our two question banks. Choose an answer to see why each option is right or wrong.
1. A 22-year-old man with type 1 diabetes arrives with DKA. pH 7.12, glucose 25 mmol/L (450 mg/dL), potassium 3.1 mmol/L. Fluids have been started. What should happen next?
Answer: Replace potassium before starting insulin and call the senior. Insulin lowers serum potassium. In DKA, if potassium is below 3.5 mmol/L, insulin is delayed while potassium is replaced, with senior input and cardiac monitoring.
- Give a bolus of 10 units insulin IV: Boluses are not used, and potassium is low.
- Give IV sodium bicarbonate: Bicarbonate is not routine and lowers potassium further.
- Start insulin and check potassium in 4 hours: Potassium below 3.5 must be corrected first.
- Start insulin at 0.1 units/kg/hour now: Insulin drives potassium into cells and can cause a dangerous fall.
2. A 70 kg man is being treated for DKA with a fixed-rate insulin infusion. Four hours in, glucose is 12.8 mmol/L (230 mg/dL) and blood ketones are 2.9 mmol/L. What is the best change?
Answer: Add 10% dextrose and continue the insulin. In DKA the insulin is driven by ketones, not sugar. When glucose falls below 14 mmol/L (252 mg/dL), add 10% dextrose (for example 125 mL/hour) so the fixed-rate insulin can continue until ketones are below 0.6 mmol/L.
- Give more 0.9% saline only: The sugar will fall too low without dextrose.
- Halve the insulin rate: The fixed rate is continued until ketones clear.
- Switch to subcutaneous insulin: Only once DKA has resolved and the patient is eating.
- Stop the insulin infusion: Ketones are still high; stopping insulin lets ketoacidosis continue.
3. A 48-year-old man with type 2 diabetes on empagliflozin has been vomiting for two days. Glucose is 10 mmol/L (180 mg/dL), blood ketones 4.5 mmol/L, pH 7.2, bicarbonate 12. What is the diagnosis?
Answer: Euglycaemic diabetic ketoacidosis. SGLT2 inhibitors can cause DKA with near-normal glucose. Treat as DKA, with dextrose from the start alongside insulin, and stop the SGLT2 inhibitor.
- Hyperosmolar hyperglycaemic state: HHS has very high glucose and little ketosis.
- Lactic acidosis from metformin: The ketones explain the acidosis here.
- Starvation ketosis: Starvation ketones rarely cause acidosis this severe.
- Gastroenteritis with mild dehydration only: Ketones 4.5 with acidosis is DKA.
4. A 19-year-old with type 1 diabetes has glucose 28, pH 7.1, HCO₃ 8, ketones 5 and K⁺ 4.0 mmol/L. After fluids, what insulin regimen is used?
Answer: Fixed-rate IV insulin 0.1 U/kg/h. DKA: glucose > 11, ketones > 3 (or ++ urine), pH < 7.3 or HCO₃ < 15. Treatment: IV 0.9% saline (1 L over 1 h, then slower), fixed-rate IV insulin 0.1 U/kg/h; continue long-acting insulin; add 10% dextrose when glucose < 14 to continue insulin until ketones clear; potassium replacement (40 mmol/L when K 3.5–5.5; hold insulin if K < 3.5). Monitor hourly glucose/ketones, 2-hourly K/VBG. Find precipitant (infection, missed insulin).
- Subcutaneous insulin only: Subcutaneous absorption is unreliable in DKA.
- IV insulin bolus 20 U then stop: A single bolus is not standard.
- Withhold insulin until glucose < 15: Insulin must not be withheld; add dextrose when glucose falls.
5. A man with type 2 diabetes on empagliflozin is unwell after surgery with vomiting and Kussmaul breathing; glucose 9.8 mmol/L, pH 7.15, bicarbonate 10, ketones 5.2. What is the diagnosis?
Answer: Euglycaemic DKA. SGLT2 inhibitors (empagliflozin, dapagliflozin) can precipitate DKA with near-normal glucose (< 14 mmol/L) — triggers: surgery, acute illness, fasting, low carbohydrate intake, insulin dose reduction, alcohol. Diagnose by ketones and acidosis regardless of glucose. Treat as DKA: fluids, fixed-rate insulin with dextrose (to allow insulin while glucose is normal), potassium; stop SGLT2i. Withhold SGLT2 inhibitors 3 days before surgery and during acute illness (sick-day rules).
- Lactic acidosis from metformin: Metformin lactic acidosis does not cause raised ketones.
- Post-operative starvation ketosis: Starvation ketosis rarely drops pH this low.
- Hyperosmolar state: HHS has high glucose and osmolality.
6. Na⁺ 140, Cl⁻ 100, HCO₃⁻ 10 mmol/L, with pH 7.2. What is the anion gap and what does it suggest?
Answer: 30; high anion gap acidosis. Anion gap = Na⁺ − (Cl⁻ + HCO₃⁻) = 140 − 110 = 30 (normal about 8–12). A high gap means unmeasured acids: MUDPILES (methanol, uraemia, diabetic ketoacidosis, propylene glycol/paraldehyde, iron/isoniazid, lactic acidosis, ethylene glycol, salicylates). Normal gap acidosis comes from diarrhoea or renal tubular acidosis.
- 10; normal anion gap acidosis: Calculation is wrong.
- 50; respiratory acidosis: Calculation is wrong; this is metabolic.
- 30; metabolic alkalosis: pH is low, not alkalosis.
- 20; normal: Calculation is wrong.
7. In diabetic ketoacidosis, which ketone body is present in the greatest amount, and which is missed by the standard urine nitroprusside test?
Answer: β-hydroxybutyrate. In DKA, low insulin and high glucagon drive fatty acid oxidation and ketogenesis in the liver. β-hydroxybutyrate is the main ketone body (often 3–10 times acetoacetate), but nitroprusside urine strips detect only acetoacetate (and acetone). Blood β-hydroxybutyrate testing is preferred. Acetone gives the fruity breath.
- Acetoacetate: Detected by nitroprusside; less abundant.
- Acetone: Volatile; causes fruity breath.
- Acetyl-CoA: Precursor, not a ketone body.
- Lactate: Not a ketone body.
References and dose sources
- JBDS: Management of diabetic ketoacidosis in adults
- ADA/EASD/JBDS consensus: hyperglycaemic crises in adults (2024)
- NICE NG17 — type 1 diabetes in adults
- Sodium chloride (normal saline, 3% saline) dosing: Drugs.com: Sodium chloride dosage (see also our sodium chloride (normal saline, 3% saline) dose page)
- Dextrose (glucose) dosing: Drugs.com: Dextrose dosage (see also our dextrose (glucose) dose page)
- Potassium chloride dosing: Drugs.com: Potassium chloride dosage (see also our potassium chloride dose page)
- Insulin (soluble, regular) dosing: Drugs.com: Insulin regular dosage (see also our insulin (soluble, regular) dose page)
International guidance is linked where it reflects good practice. Where your hospital’s protocol differs, follow your hospital.