Postnatal organic causes of mental retardation.

A study of 1137 retarded children from Western Ontario revealed 129 (11.3%) in whom retardation was first noted after a specific postnatal event. Eighty-three of these were boys. The most common cause of postnatal cerebral injury in this series was a syndrome of unknown etiology characterized by the sudden onset of fever, convulsions and coma which occurred in 45 patients. The nature of this syndrome is discussed and the necessity for early treatment emphasized. Other postnatal causes of retardation are classified according to frequency, as encephalitis, accidents, meningitis and a miscellaneous group consisting of epilepsy and tumours.