Aqueduct stenosis

Aqueductal stenosis is 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 of ~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, aqueductal stenosis has different etiologies 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 intellectual disability, 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.

Adults with late-onset idiopathic aquedcutal stenosis more commonly have chronic onset of neurological symptoms 6.

An antenatal exam can show features of fetal hydrocephalus with a near-normal posterior fossa. There can be secondary thinning of the cortical mantle as well as secondary macrocephaly.

MRI better delineates the extent of obstructive hydrocephalus with an 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. web, tumor). 

  • sagittal T2: the absence of flow-void signal intensity at the aqueductal level has been suggested as a sign of aqueductal stenosis 3
  • sagittal CISS: best demonstrates obstructing web
  • CSF flow study: decreased aqueductal stroke volume and peak systolic velocity

Treatment is often either with a endoscopic third ventriculostomy or ventriculoperitoneal shunting.

There is a small recurrence risk (~4%) for congenital cases even when it is not X linked.

Article information

rID: 928
Synonyms or Alternate Spellings:
  • Aqueductal stenosis
  • Stenosis of the aqueduct of Sylvius
  • Perinatal aqueductal stenosis
  • Perinatal aqueduct stenosis
  • Perinatal aqueductal atresia
  • Aqueduct stenoses
  • Aqueduct stenosis (AS)

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Cases and figures

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  • Case 2
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  • Case 3
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  • Case 4: aqueduct webs
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  • Axial T1
    Case 5
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  • Case 6
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  • Case 7
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  • Case 8
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  • Case 9
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  • Case 10
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  • Case 11
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  • Case 12: aqueductal web
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  • Case 13: with setting sun appearence to eyes
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  • Case 14
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  • Case 15: due to a web
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