Hypoglycemia and its Causes

A working definition of clinical hypoglycaemia is a low blood glucose level less than 3.0 mmol/l, associated with characteristic, but non-specific, symptoms which are reversed by the administration of glucose.

Causes

1. Exogenous causes

•     IV or Subcutaneous Insulin therapy
•     Oral hypoglycaemics (overdose)
•      Ethanol (inhibit gluconeogenesis)
•      Drugs: salicylates, beta-adrenergic blockers

Image courtesy of CDC/ Amanda Mills

2. Endogenous causes

Reactive

•         Idiopathic (functional)
•         Early diabetes mellitus (adult onset)
•         Autoimmune hypoglycaemia

Fasting

•         Insulinoma
•         Non-pancreatic neoplasms
•         Adrenocortical deficiency
•         Hypopituitarism (growth hormone deficiency)
•         Liver failure (impaired gluconeogenesis or gluconeogenesis storage)
•         Renal failure (loss of glucose in urine)
•         Sepsis
•         Autoimmune hypoglycaemia