Sylvian Aqueduct Syndrome (SAS) occurs with lesions around the Sylvian aqueduct.


Sylvian Aqueduct Syndrome (SAS) consists of:

(1) loss of upward gaze (Parinaud’s syndrome)

(2) retraction nystagmus

(3) paralysis or spasm of convergence (convergence nystagmus)

(4) vertical nystagmus on gazing up or down

(5) pupillary abnormalities (anisocoria, absence of reaction to light, other)

(6) variable ophthalmologic findings (myopia, palsies of extraocular muscles)


Possible causes of SAS:

(1) pinealoma

(2) other tumors (midbrain glioma, neurofibromatosis)

(3) tertiary syphilis

(4) hydrocephalus

(5) shunt overdrainage

(6) vascular lesion in the region of the midbrain (arteriovenous malformation)

(7) encephalitis

(8) trauma

(9) multiple sclerosis

(10) congenital


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