Lightning Learning: Hypoglycaemia in Adults
STOP!
In diabetics, hypoglycaemia is defined as a CBG <4.00 mmol/L (‘four is the floor’).
In non-diabetics, hypoglycaemia is often defined as a CBG <3.3 mmol/L.
Risk factors in diabetics:(1)
Recent change in medication regime; fasting (e.g. during Ramadan); iatrogenic (e.g. prescribing VRIII without glucose); renal impairment; alcohol consumption; advanced age; intercurrent illness; exercise and heat.
Important causes in non-diabetics:
Alcoholic chronic liver disease and (rarely) insulinoma.
Hypoglycaemia should be excluded in anyone presenting with potentially neuroglycopenic symptoms:(2)
- Reduced level of consciousness
- Unusual behavior/confusion
- Seizures
- Features of stroke
LOOK
True hypoglycaemia is diagnosed using Whipple’s Triad:
- Hypoglycemia symptoms
- Accompanying low CBG
- Resolution of symptoms after raising blood glucose to normal
Clinical features:
- Autonomic symptoms, e.g. pallor, sweating, tachycardia, hunger
- Neuroglycopenic symptoms
- Nonspecific symptoms, e.g. general malaise, headaches, nausea
Don’t forget!
Loss of hypoglycaemia awareness and warning symptoms are common in patients with long-standing diabetes.
Severe prolonged hypoglycaemia can cause cerebral oedema and brain damage.
HYPOGLYCAEMIA CAN BE FATAL
LEARN
Beware of iatrogenic hypoglycaemia when managing patient with hyperkalaemia or DKA.
Hyperkalaemia
- Monitor CBG at 0, 15, 30, 60 & 90 mins, and at 2, 3, 4 and 6 hrs
Diabetic Ketoacidosis
- Prescribe 10% glucose 500 ml (with 20 mmol KCl if serum K is 3.5-5.5mmol/L) at 125ml/hr to run alongside 0.9% NaCl as soon as blood glucose is <14 mmol/L
- Switch patients from fixed rate IV insulin infusion to variable rate or s/c insulin once blood ketones are <0.6mmol/L
For the management of hypoglycaemia in diabetics see our local guidance.(3)
References
- Diabetes and Hypoglycemia (Diabetes.co.uk)
- Hypoglycaemia (RCEM Learning)
- Algorithm for the treatment of Hypoglycaemia in Diabetic Adults (UHL)
