High blood sugar on the ward
Is the patient unwell, and are there ketones? That decides between DKA, HHS and just adjusting the regular insulin.
Nurse: "Bed 14's sugar is 22." (22 mmol/L, 396 mg/dL.) He is 58, admitted with pneumonia, on prednisolone 40 mg and his usual metformin and gliclazide. Last two sugars 16 and 19 mmol/L (288 and 342 mg/dL).
What do you ask before you walk over?
- Ask: how is the patient?Vomiting, drowsy, breathing fast, abdominal pain: go now.
- Check ketonesEvery sugar above 14 mmol/L (252 mg/dL) in type 1, and in anyone unwell.
- Repeat the sugarWash the finger. Check it's not a drip-arm sample.
- Look for the reasonInfection, steroids, missed insulin, dextrose drip, feeds, pain.
- Never stop basal insulin in type 1Even if nil by mouth.
- Correction dose per your hospital chartThen fix the regular regimen the next day.
- Write the planNext sugar time, who to call, when to call.
- Ketones 1.5 or more
- Vomiting or unable to keep fluids down
- Drowsy or confused
- pH below 7.3 or bicarbonate below 15
- Sugar above 30 mmol/L (540 mg/dL)
- Type 1 with insulin missed
- DKA in type 1 (including euglycaemic DKA on SGLT2 inhibitors)
- HHS in elderly type 2
- Sepsis driving the sugar up
- Pancreatitis
- A dextrose drip running
| Check ketones | Sugar above 14 mmol/L (252 mg/dL), or any type 1 patient who is unwell |
| Ketones below 0.6 mmol/L | Normal |
| Ketones 0.6–1.5 | Raised: extra insulin, recheck in 2 hours |
| Ketones 1.5–3.0 | At risk of DKA: senior review now |
| Ketones 3.0 or more | DKA likely if sugar above 11 mmol/L (198 mg/dL) or known diabetes, plus bicarbonate below 15 or pH below 7.3 |
| HHS | Sugar 30 mmol/L (540 mg/dL) or more, osmolality 320 or more, without significant ketones |
| Target range on the ward | Usually 6–10 mmol/L (108–180 mg/dL), 4–12 (72–216) acceptable |
Check every dose against a current drug reference and your hospital protocol.
On this page
The decision in one picture
- Gas: pH, bicarbonate
- DKA if pH below 7.3 or bicarbonate below 15
- Start the DKA protocol
- see the DKA guide
- Senior now
- Extra rapid-acting insulin per chart
- Recheck sugar and ketones in 1–2 hours
- Correction insulin
- Fluids if dry
- Recheck in 2 hours
- Correction dose per chart
- Find the cause
- Adjust the regular insulin tomorrow
These can cause euglycaemic DKA: ketoacidosis with a sugar that is only mildly raised, even below 11 mmol/L (198 mg/dL). If a patient on one is unwell, vomiting or fasting, check ketones whatever the sugar. Stop the drug while acutely ill.
HHS: the slow, dry, dangerous one
- Usually older, type 2, often not known diabetic. Days of thirst and passing urine, then drowsiness.
- Sugar 30 mmol/L (540 mg/dL) or more, very dry, osmolality 320 mOsm/kg or more, no significant acidosis.
- Calculated osmolality = 2 × sodium + glucose + urea (all in mmol/L). With Pakistani units: 2 × Na + glucose (mg/dL) ÷ 18 + urea (mg/dL) ÷ 6.
- Fluids first (0.9% saline). Insulin is started later and at a lower rate than DKA, once the sugar stops falling with fluids alone. Drop sodium and sugar slowly. Prophylactic enoxaparin. Senior and HDU.
Why is the sugar high?
| Cause | Clue | Fix |
|---|---|---|
| Infection | Fever, new symptoms | Treat it; sugar settles |
| Steroids | Morning prednisolone, sugars high afternoon and evening | Morning intermediate-acting insulin or gliclazide, per diabetes team |
| Missed or held insulin | Nil by mouth, "insulin held" | Restart basal; never stop it in type 1 |
| Dextrose drip or feeds | Check the drip chart | Adjust, cover with insulin |
| Hospital food, snacks | After meals | Review the regimen |
| Pain, stress | Post-op | Treat pain |
Correction insulin
- Use your hospital's correction (supplemental) chart. It ties the extra rapid-acting insulin dose to the sugar and the patient's usual total daily insulin.
- Correction is a patch, not a plan. If you need it more than twice in a day, the regular regimen needs changing.
- Do not give correction doses at bedtime in the elderly or frail without a recheck plan: overnight lows are dangerous.
- Recheck the sugar 2 hours after a correction dose.
Common mistakes
- Stopping all insulin in a type 1 patient who is nil by mouth.
- Giving a big correction dose at midnight and not rechecking.
- Not checking ketones because "it's type 2".
- Missing euglycaemic DKA on an SGLT2 inhibitor.
- Chasing every high sugar instead of fixing the regimen in the morning.
Frequently asked questions
What is the treatment of high blood sugar in hospital?
Check the patient and ketones first. If ketones are high or the patient is unwell, assess for DKA or HHS. If well with no ketones, give a correction dose per the hospital chart, find the cause, and adjust the regular insulin.
What sugar level is an emergency?
Any high sugar with ketones of 3 mmol/L or more, vomiting, drowsiness or fast breathing. A sugar of 30 mmol/L (540 mg/dL) or more in a dry, drowsy older patient suggests HHS.
Why does prednisolone raise blood sugar in the afternoon?
Morning prednisolone has its biggest effect 4–8 hours later, so sugars rise in the afternoon and evening and often settle overnight.
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 ward patient with type 1 diabetes has glucose 17 mmol/L (306 mg/dL). He feels well. What should be checked first?
Answer: Blood ketones. Check ketones in every type 1 patient with glucose above 14 mmol/L (252 mg/dL) to exclude DKA.
- Thyroid function: Not urgent.
- HbA1c: Not urgent.
- Nothing; give correction insulin: Check ketones first.
- Lipid profile: Not relevant.
2. A patient on prednisolone 40 mg each morning has glucose 7 mmol/L (126 mg/dL) at 7 a.m. and 18 mmol/L (324 mg/dL) at 4 p.m. Which treatment fits this pattern?
Answer: Morning insulin or gliclazide. Morning steroids cause afternoon and evening hyperglycaemia. Treatment given in the morning covers the peak.
- Stop the prednisolone: It's needed for the illness.
- Bedtime long-acting insulin only: The peak is in the afternoon.
- Correction insulin at midnight: Risks overnight lows.
- No treatment needed: 18 mmol/L needs treatment.
3. An older patient is very dry and drowsy with glucose 38 mmol/L (684 mg/dL), osmolality 345 mOsm/kg and ketones 0.8 mmol/L. What is the diagnosis?
Answer: Hyperosmolar state. HHS: glucose 30 mmol/L (540 mg/dL) or more, osmolality 320 or more, little ketosis. Fluids first, insulin later at a lower rate.
- Lactic acidosis: Not this pattern.
- Simple hyperglycaemia: The osmolality and drowsiness make it HHS.
- Hypoglycaemia: No.
- DKA: Ketones are low.
4. An elderly woman with type 2 diabetes is confused and severely dehydrated. Glucose is 52 mmol/L, osmolality 365 mOsm/kg, ketones 0.8, pH 7.34. What is the main initial treatment?
Answer: IV 0.9% saline, gradual correction. Hyperosmolar hyperglycaemic state: severe hyperglycaemia (> 30), osmolality > 320, minimal ketosis, profound dehydration (often 10–20 L deficit), elderly type 2 diabetics, precipitated by infection. Treat with IV 0.9% saline first (glucose falls with fluid alone); start low-dose insulin (0.05 U/kg/h) only when glucose stops falling with fluids or if ketotic; aim osmolality fall 3–8 mOsm/kg/h. High VTE risk — prophylactic LMWH. Higher mortality than DKA.
- Immediate high-dose insulin bolus: A high-dose insulin bolus causes a rapid osmolality fall.
- Hypotonic 0.45% saline rapidly: Rapid hypotonic fluid causes dangerous shifts.
- Bicarbonate infusion: She is not acidotic.
5. A type 1 diabetic has high morning glucose. Checking at 3 a.m. shows glucose of 2.8 mmol/L. What explains the morning hyperglycaemia and what should be done?
Answer: Somogyi effect — reduce evening insulin. Somogyi effect: nocturnal hypoglycaemia triggers counter-regulatory hormones causing rebound morning hyperglycaemia — reduce the evening/bedtime insulin or give a bedtime snack. Dawn phenomenon: early-morning rise in GH/cortisol causes hyperglycaemia without nocturnal hypoglycaemia (3 a.m. glucose normal or high) — increase or move the basal insulin. The honeymoon period is temporary remission soon after diagnosing type 1 diabetes due to residual β-cell function.
- Dawn phenomenon — increase evening insulin: 3 a.m. glucose would be normal/high.
- Honeymoon period — stop insulin: The honeymoon phase doesn’t cause nocturnal hypoglycaemia with rebound; insulin is still needed.
- Insulin resistance — add metformin: Metformin doesn’t address nocturnal hypoglycaemia; reduce evening insulin.
6. 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.
7. Which effect does insulin have on metabolism?
Answer: Promotes glycogen and fat storage. Insulin is the 'fed state' hormone: it promotes glucose uptake (GLUT4), glycogen synthesis, lipogenesis and protein synthesis, and inhibits gluconeogenesis, glycogenolysis, lipolysis and ketogenesis. Glucagon (fasting) does the opposite in the liver via cAMP. Muscle has no glucagon receptors.
- Stimulates lipolysis: Glucagon, catecholamines.
- Stimulates glycogen breakdown: Glucagon, adrenaline.
- Stimulates ketone production: Low insulin, high glucagon.
- Increases protein breakdown: Cortisol, catabolism.
References and dose sources
- JBDS inpatient care guidelines (DKA, HHS, steroids, inpatient insulin)
- NICE NG17: Type 1 diabetes in adults
- 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.