Incidence and Possible Relation to Athetosis of Neonatal Jaundice of Unknown Aetiology.

It is still not clear whether jaundice of unknown aetiology, developing during the neonatal period, is of significance for the subsequent development of athetosis and related diseases. In a previous study (Trolle, 1961), the author calculated that among children who have had neonatal jaundice of unknown aetiology, athetosis of later onset is so uncommon that the decision to perform an exchange transfusion merely on the basis of an arbitrarily selected bilirubin value must be regarded as unjustified. As an example, it was calculated that if routine exchange transfusion were performed on the indication of a bilirubin value of 20 mg./100 ml. and over, a total of 2,140 transfusions would have been performed in mature infants in order to save one from athetosis, while there is a present risk that 21 would have died as a result of the exchange. In the case of prematures, 92 exchange transfusions would have been necessary in order to save one child from athetosis, but with the present risk four would have died as a result of the transfusion. The criterion for exchange transfusion cannot therefore be based only on the serum bilirubin value. In obstetric departments and children's departments, this question of exchange transfusion in the newborn suffering from jaundice of unknown aetiology is constantly arising. In what follows, therefore, three questions will be discussed. First, since the cause of jaundice in each individual infant appears to be unknown, is it the result of a number of known clinical factors? Second, in how many cases can the jaundice be considered to play a role in the subsequent development of athetosis? Third, why do some jaundiced newborn infants subsequently develop athetosis, while others, equally or