![]() ![]() dorsal midbrain syndrome, Argyll-Robertson pupil, pineal tumor, Wernicke’s encephalopathy), or a lesion in the efferent pathway (e.g., ciliary ganglion, post-ganglionic. Until better evidence settles the localization of the AR pupil, it is appropriate to screen patients with bilateral tonic pupils for syphilis. LND may result from a lesion in the afferent pupillary pathway (e.g., retinal ganglion cells, optic nerve, chiasm, tract, lateral geniculate body), a pretectal lesion (e.g. If segmental iris sphincter palsy is found and the light-near dissociation has tonic features, one must conclude that the mechanism of the pupil disorder is a ciliary (peripheral) rather than a midbrain (central) denervation. Resolving the issue about the location of the syphilitic lesion that produces the AR pupil will depend on careful examination of patients with techniques designed to disclose segmental palsy of the iris. Spector RH, Walker HK, Hall WD, Hurst JW. Argyll Robertson pupils (neurosyphilis) References. Optic tract lesions (e.g., infarction) Clinical features. Pupillary size can vary in response to light intensity and neurologic stimuli. However, lesions in this region have not been reliably demonstrated in syphilis. The pupil is an opening in the center of the iris through which light enters the eye. Because the AR pupil lacks these features, it has been attributed to a dorsal midbrain lesion that interrupts the pupillary light reflex pathway but spares the more ventral pupillary near reflex pathway. Such features are considered typical of the light-near dissociation of Adie syndrome and of neuropathic tonic pupils, where damage to the ciliary ganglion or ciliary nerves is believed to be the mechanism. In parenchymatous neurosyphilis, the CSF reaginic and serum treponemal tests are reactive, and CSF typically has lymphocytic pleocytosis and elevated protein. Most descriptions of the AR pupil do not mention segmental iris sphincter constriction, or slow, sustained constriction with a near vision effort. In neurosyphilis, most symptoms and signs, except for Argyll Robertson pupil, are nonspecific, so that diagnosis relies heavily on a high index of clinical suspicion. The Argyll Robertson (AR) pupil has been defined as a pupil that is small and constricts poorly to direct light but briskly when a target within reading distance is viewed ("light-near dissociation").
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |