Name some secondary causes of aqueductal stenosis?
Extrinsic compression: tectal plate glioma; pineal tumour; posterior fossa tumour; cerebral vascular malformation. Intrinsic stenosis/obstruction: previous infection (meningitis/ventriculitis); subarachnoid haemorrhage (SAH).
What may you see when examining the child's eyes?
Setting sun phenomenon. The eyes appear driven downward. The lower portion of the pupil may be covered by the lower eyelid, and sclera may be seen between the upper eyelid and the iris.
Non-contrast CT of the brain demonstrates marked hydrocephalus involving the lateral and third ventricles but sparing the fourth ventricle. The floor of the third ventricle is ballooned outwards (downward) and there is funnelling of the superior part of the aqueduct. The anterior fontanelle is gaping.