[Subdural or sub-arachnoid pericerebral effusions in the infant with subdural or subarachnoid localisation (author's...

Twenty-seven "subdural" effusions in infants were treated, according to our previously suggested method: a simple external drainage, followed ater one week by an internal peritoneal shunt, if the effusion did not dry up by this time. Daily electrophoresis of the fluid obtained by external drainage has been performed in 20 cases, either until the disappearance of the effusion or until the peritoneal shunting after 7 days. In 8 persistent and in 5 rapidly disappearing effusions, cerebro-spinal fluid was immediately present or appeared during the first week, simultaneously with a lowering of the total protein content. In the other 7 rapidly disappearing effusions, the protein content remained high and a conspicuous plasmatic transsudation was disclosed; the possibility that cerebro-spinal fluid could be present even in some of those last cases is discussed. The fact that some effusions display, from the onset, the characteristics of cerebro-spinal fluid, leads to the question of their subarachnoid rather than subdural localisation. For this reason, we prefer to use the less committed denomination of pericerebral effusions, in which we may distinguish subdural effusions, with or without cerebro-spinal fluid, and subarachnoid effusions. Nevertheless, it is not always easy to establish the pathogenic character of an effusion revealed by CT-scan. Pressure measurements by fontanometry appear to be a useful examination for that purpose.