In this article, we’ll provide a quick overview of the treatment and investigations of patients with hypoglycaemia.

If you prefer video tutorials, check out Sweet & Salty.


Diabetic: Glucose <4mmol/L usually warrants treatment.

Non-Diabetic: Cut off <2.8mmol/L.
Above this value is usually physiological, but if below 3.5mmol/L with symptoms that improve on correction, an endocrine referral is warranted.

Emergency Treatment

Conscious – 100-150ml of juice or 5-7 tablets of glucose or 4 jelly babies.
Recheck every 10-15 minutes until 4 mmol/L.

Unconscious – 100ml of 20% glucose or 200ml of 10% glucose intravenously
If unable to obtain IV access or difficult to obtain, give Glucagon 1mg IM.

Once the patient has recovered, give them a longer-acting carbohydrate snack such as a biscuit or slice of toast to ensure they don’t develop hypoglycaemia. You might need to give a continuous glucose infusion to a patient with long-acting insulin on board particularly if they have AKI impairing insulin clearance.

Important Tips

  • Nurses should be able to give the emergency treatment with a verbal order in an emergency
  • Glucagon doesn’t work well in a malnourished/liver disease patient (minimal glycogen stores to release) & can cause significant nausea so do give an antiemetic
  • Foods with high-fat content impair sugar release therefore avoid things like chocolate
  • Avoid 50% dextrose as this is too viscous & 5% dextrose as this has far too little sugar. 10% or 20% tends to be what is typically used.
  • Don’t treat high CBGs post-treatment, it can be corrected with the next meal & also a single episode of hyperglycaemia is rarely dangerous!

Next Steps – Identify the Cause

The most common cause is a patient on diabetes medication with reduced oral intake, alcohol, infection or exercise.

Other causes
  • Sepsis
  • Starvation (if ketones are raised this can be a clue!)
  • Acute liver failure (usually acidotic and high lactate, deranged LFTs)
  • Adrenal crisis (check cortisol)
  • Rapidly spreading malignancy, usually haematological (raised lactate, history)
  • Medications e.g. Quinine, Co-Trimoxazole (Septrin)
  • Post-bariatric surgery
  • Reactive hypoglycaemia (after a large meal)
  • End of life (reconsider whether blood glucose measurement is appropriate)
  • (And very, very rarely insulinoma)

How to adjust diabetes medication

  • The most common medications to cause hypoglycaemia are insulin & sulphonylureas (i.e. gliclazide)
  • Remember that hypoglycaemia is caused by the medication before the event (i.e. early morning hypoglycaemia is caused by the evening medication)
  • If the patient is on gliclazide, reducing it by about 40mg is usually enough
  • If the hypoglycaemia is due to basal insulin (early morning/before meals) then reduce it by 10-20%. Never omit basal insulin!
  • If due to meal-time short-acting insulin, then reduce this by typically 2-4 units


  • If you’re unsure how to adjust the diabetes medication, refer to the diabetes specialist nurse
  • If the patient is complicated (e.g. on NG/TPN feed) then refer to the diabetes specialist doctor
  • If the patient does not have diabetes, have a low threshold to refer to the endocrine registrar.

For non-diabetics, it is helpful to take the following tests prior to correction

  • Lab glucose (otherwise we can’t interpret any tests below!)
  • C-peptide
  • Insulin
  • Beta-hydroxybutyrate
  • Urine sulphonylurea screen


Written by Dr Akash Doshi (Endocrine & Diabetes ST4) & Dr Tom Crabtree (Endocrine SpR)

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