[Benign idiopathic external hydrocephalus (benign subdural collection) in 39 children: its natural history and relation to familial macrocephaly].

INTRODUCTION: Benign idiopathic external hydrocephalus (BIEH) is an age-dependent disorder that is self-limiting in time and has an uncertain aetiology. PATIENTS AND METHODS: A retrospective study was conducted involving 39 patients (16 girls and 23 boys) with BIEH. The following data were analysed for each patient: age, sex, family history, history concerning pregnancy, childbirth and neonatal period, postnatal history, data from clinical records and from physical examinations, progress of psychomotor development, findings from the first and successive neuroimaging studies, results of other complementary examinations, clinical and neuroimaging situation at the last check-up that was carried out, length of clinical control, age at which subdural effusion disappeared, and any other relevant associated facts.
RESULTS: Age at diagnosis ranged from 1.33 and 25 months (mean: 8.4 months); in 38.46% of cases there was a history of macrocephalia in one of the progenitors; in four of them the presence of congenital macrocephalia was noted; in five, there was motor retardation and one of them displayed psychomotor retardation; in 15, there was an association with a slight dilatation of the lateral ventricles; the mean time of clinical control was 3.36 years; the process was seen to resolve in 14 cases; the minimum age for the disappearance of the subdural effusion was 9 months and the maximum was 8 years; macrocephalia persisted until the clinical control ended in 22 of the cases. We also noted the presence of two cases of mitochondrial encephalomyopathy, one craniosynostosis of the sagittal suture, one microdeletion 22q11.2, one a-1 antitrypsin deficiency, and one case of idiopathic bilateral congenital palpebral ptosis.
CONCLUSIONS: The subdural effusion and/or macrocephalia persist in a high percentage of these patients and sometimes there is a close relationship between this condition and benign familial macrocephalia. Despite its benignity, it can influence psychomotor or motor retardation and behavioural disorders. On rare occasions it may be associated to mitochondrial encephalomyopathy and to the microdeletion 22q11.2.