Lightning Learning: Hypoglycaemia in Adults

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:

  1. Hypoglycemia symptoms
  2. Accompanying low CBG
  3. 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

  1. Diabetes and Hypoglycemia (Diabetes.co.uk)
  2. Hypoglycaemia (RCEM Learning)
  3. Algorithm for the treatment of Hypoglycaemia in Diabetic Adults (UHL)
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