Hypoglycaemia begets hypoglycaemia

Abstract

Drug-induced (insulin/insulin secretagogue) hypoglycaemia is the most common cause of hypoglycaemia particularly in the elderly. It is estimated that hypoglycaemia of any severity occurs annually in 5-20% of patients taking antihyperglycaemic agents. Although these hypoglycaemic episodes are rarely fatal, they can be associated with serious clinical sequelae. The half-life for most sulfonylurea medications is 14-16 h; they can cause severe, prolonged hypoglycaemia. It is important to recognise, prevent and treat hypoglycaemic episodes secondary to the use of antihyperglycaemic agents. Patient education has become focused on minimising hyperglycaemia but emphasis must be placed on minimising even minor subclinical hypoglycaemia because it will contribute to a vicious cycle of hypoglycaemia begetting hypoglycaemia. Ten per cent dextrose is recommended for the reversal of all hypoglycaemic episodes rather than the conventional 50% dextrose. Octreotide can be an option for recurrent and relapsing hypoglycaemia in an acute setting.

A case of severe relapsing sulphonylurea-induced hypoglycaemia

“…In patients with diabetes mellitus, hypoglycaemia is defined as a plasma glucose level of ≤3.9 mmol/L 5. The American Diabetes Association and the Endocrine Society Workgroup on hypoglycaemia recommends classifying hypoglycaemia in diabetics into five categories6:…”

“…Hence, due to gliclazide's prolonged action, glucose needs to be monitored every 1–2 hours and ideally a slow infusion of 5% or 10% dextrose should be administered in cases of recurrent hypoglycaemic episodes 5. A slow infusion is preferred from a bolus infusion as a bolus represents an excessive dextrose load and this may result in excess insulin secretion from the sulphonylurea sensitised pancreatic β-cells resulting in rebound hypoglycaemia 5 9. For the same reason, glucagon should also be avoided as it may also cause a reactive hypoglycaemia due to excessive insulin release in response to the glucagon-induced hyperglycaemia 5.…”

“…A slow infusion is preferred from a bolus infusion as a bolus represents an excessive dextrose load and this may result in excess insulin secretion from the sulphonylurea sensitised pancreatic β-cells resulting in rebound hypoglycaemia 5 9. For the same reason, glucagon should also be avoided as it may also cause a reactive hypoglycaemia due to excessive insulin release in response to the glucagon-induced hyperglycaemia 5. Furthermore, glucagon can stimulate insulin release directly causing a delayed drop in plasma glucose 9.…”

“…The dose and duration of octreotide administration is still a controversial issue. One might consider a single 75 µg subcutaneous dose of octreotide after 50 mL of 50% dextrose infusion if patients are still having recurrent hypoglycaemia 5. Other dose regimens include 50–100 µg of octreotide given every 6–12 hours 11.…”

“…This allows patients to detect and correct hypoglycaemic episodes earlier. In addition, in view of the prolonged action of sulphonylureas, physicians should be made aware that it is unsafe to discharge patients with sulphonylurea-induced hypoglycaemia, after the initial hypoglycaemic event is corrected as these hypoglycaemic episodes may recur 5…”