a condition marked by dilatation of the cerebral ventricles, most often occurring secondarily to obstruction of the cerebrospinal fluid pathways and accompanied by an accumulation of cerebrospinal fluid within the skull, the fluid is usually under increased pressure, but occasionally may be normal or nearly so. It is typically characterised by enlargement of the head, prominence of the forehead, brain atrophy, mental deterioration and convulsions, may be congenital or acquired and may be of sudden onset (acute h.) or be slowly progressive (chronic or primary b.).
Origin: gr. Kephal = head