Hypoglycaemia or low blood sugar occurs when a patient with DIABETES MELLITUS suffers an imbalance between carbohydrate/glucose intake and INSULIN dosage. If there is more insulin than is needed to help metabolise the available carbohydrate, it causes a range of symptoms such as sweating, trembling, pounding heartbeat, anxiety, hunger, nausea, tiredness and headache. If the situation is not quickly remedied by taking oral sugar – or, if severe, giving glucose by injection – the patient may become confused, drowsy and uncoordinated, finally lapsing into a COMA. Hypoglycaemia is infrequent in people whose diabetes is controlled with diet and oral HYPOGLYCAEMIC AGENTS.

Treatment of acute hypoglycaemia depends upon the severity of the condition. Oral carbohydrate, such as a sugary drink or chocolate, may be effective if the patient is conscious enough to swallow; if not, glucose or GLUCAGON by injection will be required. Comatose patients who recover after an injection should then be given oral carbohydrates. An occasional but dangerous complication of coma is cerebral oedema (see BRAIN, DISEASES OF – Cerebral oedema), and this should be considered if coma persists. Emergency treatment in hospital is then needed. When the patient has recovered, management of his or her diabetes should be assessed in order to prevent further hypoglycaemic attacks.