[Differential diagnosis and therapy of hypoglycemia in childhood]

Occurrence of hypoglycaemia is directly connected to fuel balance. Compared to free fatty acids, glucose is rapidly exhausted. Therefore, besides disturbances in available glucose (i.e. defects in gluconeogenesis or glycogenolysis) as well as their hormonal control, defects of beta-oxidation might be possible causes. According to recent investigations they occurred with similar frequency. A blood glucose level of 2.6 mmol/l (= 47 mg%) already represents a critical concentration of brain function. Based on pathophysiological concepts concentrations of glucose, free fatty acids, ketone bodies and insulin must be determined from a single plasma sample. Together with case history and clinical symptom findings, these parameters are useful to get a reliable tentative diagnosis. Therefore, descriptions like "ketotic" or "idiopathic" hypoglycaemia can be avoided and suitable treatment can be started. Suspected diagnosis must be confirmed by means of chromatographic, enzymatic, and if necessary histological investigations. Successful treatment depends mainly on early diagnosis. This is of importance in case of surgery in organic hyperinsulinism, but likewise for advisory help to families with infants suffering from beta-oxidation defects, to avoid prolonged fasting.