[Clinical suspicion of inborn errors of metabolism]

A number of inherited metabolic disorders are diagnosed by means of the nationwide newborn screening programme, usually before the first clinical signs occur. As for the rest of the varied metabolic disorders, knowledge and intuition of the paediatrician is a prerequisite for selection of patients for further metabolic investigation (selective screening procedure). Clinical symptoms of the most important metabolic diseases can be classified according to their pathophysiological background as: "intoxication type, energy deficiency type, storage type, neurodegenerative type". Especially in the first year of life, clinical features are unspecific: psychomotoric retardation, muscular hypotonia, cerebral convulsions, recurrent vomiting, sepsis-like conditions. In these cases indication for metabolic screening is broad. Especially in older children some clinical symptoms can be specific for a metabolic disorder: distinctive odour of urine, changes in hair, skin or eyes, organomegaly, skeletal changes. Recently, Reye-like syndrome, stridor, macrocephaly and vague, cerebral ischaemic episodes have been described in association with a metabolic defect. In conclusion, experience has shown that only a small number of metabolic disorders will be diagnosed from the typical clinical picture alone. In most cases a selective screening procedure leads to diagnosis because initial symptoms are unspecific.