<prompt> Which of the following is the most common cause of congenital hydrocephalus?CraniosynostosisIntra uterine meningitisCongenital aqueductal stenosisVein of Galen malformation  <response>: Ans. C. Congenital aqueductal stenosisObstructive or noncommunicating hydrocephalus develops most commonly in children because of an abnormality of the aqueduct of Sylvius Congenital aqueductal stenosis or a lesion in the fourth ventricle. Nonobstructive or communicating hydrocephalus most commonly follows a subarachnoid hemorrhage, which is usually a result of intraventricular hemorrhage in a premature infant. Among the various causes of meningitis, tuberculous meningitis has a propensity to cause hydrocephalus due to thick, tenacious exudate that obstructs the basal cistern. 