[Hypoglycaemia--diagnosis and therapy in emergencies].
Hypoglycaemia defined as blood sugar below 2.5 mmol/L, is always an important medical emergency. The primary therapy is simple and consists of iv glucose. The occurrence of hypoglycaemia is directly connected to fuel balance, determined by the availability of glucose, free fatty acids and ketone bodies. An intact fuel balance and maintenance of normal blood sugar concentration is dependent upon: (1) an adequate caloric and qualitative dietary intake; (2) afunctionally intact hepatic glucogenolytic and gluconeogenic enzyme system; (3) an adequate supply of endogenous gluconeogenic substrates (lactate, amino acids and glycerol) (4) an adequate energy supply provided by the beta-oxidation of fatty acids to synthesize glucose and ketone bodies and (5) a normal endocrine system (insulin, glucagon, catecholamines and growth hormone) for integrating and modulating these processes. Disturbances in each of these factors may lead to hypoglycaemia. Glucose, like oxygen, is of essential and fundamental importance for the brain metabolism. The major contribution of the brain to the basal metabolic rate (70% in neonates versus 20% in adults) is an important factor contributing to the frequency and severity of a hypoglycaemic syndrome in the paediatric age. If hypoglycaemia is suspected, blood should be obtained prior to treatment for serum glucose determination and an extra tube (5 ml) serum should be obtained and refrigerated for further investigations. The first voided urine has to be tested for ketones using a dipstick and also refrigerated for further investigations. Basic laboratory investigations, anamnestic informations and clinical findings allow rapid tentative diagnosis and determine the specialized investigations out of the refrigerated material. A rapid definitive diagnosis is important for the specific treatment and to avoid recurrent and prolonged hypoglycaemia.