hypoglycaemia

Hypoglycaemia is a condition characterized by an abnormally low blood glucose level. It is commonly defined as a plasma glucose concentration below 3.9 mmol/L (70 mg/dL). In clinical practice, glucose below 3.0 mmol/L (54 mg/dL) may be described as clinically significant. Hypoglycaemia can occur in people with diabetes and in individuals without diabetes, depending on underlying conditions or medications.

Common causes include an imbalance between glucose-lowering therapies and food intake or energy use. In diabetes, the most frequent cause is excess insulin or sulphonylurea therapy, sometimes with inadequate carbohydrate intake or increased physical activity. Non-diabetic causes include critical illness, adrenal or pituitary insufficiency, severe liver disease, alcohol intoxication, insulinoma, and sepsis.

Symptoms arise from autonomic nervous system activation and from impaired brain glucose supply. Early symptoms include shakiness, sweating, palpitations, anxiety, and hunger. As glucose falls further, neuroglycopenic symptoms may develop, such as confusion, blurred vision, difficulty concentrating, seizures, or loss of consciousness.

Diagnosis relies on measuring plasma glucose during or after symptomatic episodes. Point-of-care glucose meters can aid rapid assessment but plasma glucose measurement is preferred for confirmation. A diagnosis is supported when symptoms resolve after administration of glucose.

Management for mild to moderate hypoglycaemia in a conscious patient who can swallow includes 15–20 grams of fast-acting carbohydrate (for example glucose tablets or juice), with rechecking after about 15 minutes and a follow-up snack if needed. If the patient cannot swallow or is unconscious, administer parenteral glucagon or intravenous dextrose as available, with monitoring. Long-term management focuses on identifying causes, adjusting medications, preventing recurrence, and educating patients and caregivers. Continuous glucose monitoring can help detect and prevent episodes.