In a patient with diabetes - <4 mmol/L
In a patient without diabetes - <2.8 mmol/L (this is important to remember, blood glucose of 3.4 mmol/L in a fasting adult is physiological!)

Treat ASAP – and if unconscious or confused this is a medical emergency

If conscious
Oral fast-acting carbohydrate such as
  • 120 ml Lucozade
  • 150 ml Orange juice
  • 4 jelly babies
  • 5-7 glucose tablets
Avoid chocolate or foods with high-fat content, they are too slowly absorbed to be effective.

Recheck glucose in 10-15 mins – rinse and repeat until >4 mmol/L then consider longer-acting carbohydrates such as biscuits or toast.

If unconscious
This is a medical emergency!
  • 100 ml of 20% dextrose IV or 200 ml of 10% dextrose (depending on local guidelines/availability). 
50 ml of 50% dextrose can be used but can be difficult to administer due to viscosity & is often not available. 5% dextrose is NOT effective.
  • If unable to obtain IV access or delay to IV treatment – Glucagon 1mg IM
Nurses can give this as an emergency in most trusts whilst you're on your way (i.e. a PGD medication). Glucagon can make people feel really sick so prescribe an anti-emetic before you leave.

Glucagon will be less effective in anyone who is starved or with liver disease as there will be less hepatic glycogen to break-down and correct hypoglycaemia

Check glucose every 10-15mins and rinse repeat until >4mmol/L

Once corrected
Avoid treating high CBGs post-treatment, it can be corrected at the next meal when a correction dose can be given.

Long-acting carbohydrate once able to eat and drink – will need a larger portion to replace hepatic glycogen stores if Glucagon used

Look for causes
  • review insulin doses and medications
  • infection
  • exercise
  • alcohol
Never omit insulin, but decrease doses if required

Consider Diabetes referral

Hypoglycaemia in patients without diabetes
Remember <2.8mmol/L!)

Causes can include:
  • 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: Quinine, Co-Trimoxazole (Septrin)
  • post-bariatric surgery
  • reactive hypoglycaemia
If possible consider taking blood when glucose <3mmol/L for – glucose, C-Peptide, Insulin and Cortisol before correcting blood glucose if safe to do so – this can help the Endocrine team diagnose an insulinoma vs. covert administration of insulin!

Diabetes & Endocrine on-call SpR

In most hospitals, the same person covers both, but if different teams:
  • Diabetes team for hypoglycaemia in a patient with diabetes on treatment 
  • Endocrine team for hypoglycaemia in a patient without diabetes
Written By Dr Tom Crabtree (SpR)