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