Aqueductal stenosis (AS) is a the most common cause of congenital obstructive hydrocephalus, but can also be seen in adults as an acquired abnormality.
Congenital aqueductal stenosis has an estimated incidence is at ~1:5000 births although the reported range varies greatly (3.7:1,000,000 to 1:2000) 5. Rarely it may be inherited in an X-linked recessive manner (Bickers-Adams-Edwards syndrome) 5.
In adults, as an acquired abnormality, AS has different aetiologies and thus different demographics related to them.
The clinical presentation depends on the severity and age of presentation as well as whether or not it is X-linked. In the infant enlarging head size, bulging fontanelles and gaping cranial sutures are seen. Setting sun phenomenon may also be present. In X-linked form (Bickers-Adams-Edwards syndrome) which is associated with profound mental retardation, clinical assessment would reveal bilateral adducted thumbs.
The usual symptoms and signs of raised intracranial pressure and chronic hydrocephalus may also be present, including headache, vomiting, decreased conscious state 3.
- aqueductal webs or diaphragms
Better delineates the extent of obstructive hydrocephalus, with enlargement (often marked) of the lateral and third ventricles. The aqueduct may show funnelling superiorly. The 4th ventricle is not dilated. In cases of secondary obstruction the underlying abnormality may also be evident (e.g. tumour).
Treatment and prognosis
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- 5. Urbán P. Brainstem Disorders. Springer Verlag. (2011) ISBN:3642042023. Read it at Google Books - Find it at Amazon