Argyll Robertson pupils (AR pupils) are bilateral small pupils that reduce in size on a near object (i.e., they accommodate), but do not constrict when exposed to bright light (i.e., they do not react). They are a highly specific sign of neurosyphilis; however, Argyll Robertson pupils may also be a sign of diabetic neuropathy. In general, pupils that accommodate but do not react are said to show light-near dissociation (i.e., it is the absence of a miotic reaction to light, both direct and consensual, with the preservation of a miotic reaction to near stimulus (accommodation/convergence).AR pupils are extremely uncommon in the developed world. There is continued interest in the underlying pathophysiology, but the scarcity of cases makes ongoing research difficult. Pathophysiology
The two different types of near response are caused by different underlying disease processes. Adies pupil is caused by damage to peripheral pathways to the pupil (parasympathetic neurons in the ciliary ganglion that cause pupillary constriction to bright light and with near vision). The pathophysiologic mechanism which produces an Argyll Robertson pupil is unclear, but is believed to be the result of bilateral damage to the pretectal nuclei in the midbrain. Studies have failed to demonstrate a focal localising lesion. Research has implicated the rostral midbrain in the vicinity of the cerebral aqueduct of the third ventricle as the most likely region of damage.
Smith–Magenis Syndrome (SMS), also known as 17p- syndrome, is a microdeletion syndrome characterized by an abnormality in the short (p) arm of chromosome 17. It has features including intellectual disability, facial abnormalities, difficulty sleeping, and numerous behavioral problems such as self-harm. Smith–Magenis syndrome affects an estimated between 1 in 15,000 to 1 in 25,000 individuals. Signs and symptoms
Facial features of children with Smith–Magenis syndrome include a broad and square face, deep-set eyes, large cheeks, and a prominent jaw, as well as a flat nose bridge (in the young child; as the child ages it becomes more ski-jump shaped). Eyes tend to be deep-set, close together and upwards-slanted. Eyebrows are heavy with lateral extension. The mouth is the most noticeable feature; both upper and lower lips are full, and the mouth is wide. The mouth curves downwards and the upper lip curves outwards, due to a fleshy philtrum. These facial features become more noticeable as the individual ages, as Mandible growth outstrips that of the maxilla leading to a clear midface hypoplasia. There is also a mild brachycephaly.Disrupted sleep patterns are characteristic of Smith–Magenis syndrome, typically beginning early in life. Affected individuals may be very sleepy during the day, but have trouble falling asleep and awaken several times each night, due to an inverted circadian rhythm of melatonin.People with Smith–Magenis syndrome have engaging personalities, but all also have a lot of behavioral problems. These behavioral problems include frequent temper tantrums, meltdowns and outbursts, aggression, anger, fidgeting, compulsive behavior, anxiety, impulsiveness, and difficulty paying attention.