![]() ![]() All patients presenting with a CN3 palsy should be imaged to evaluate for impending aneurysm regardless of pupil involvement, and clinicians should re-evaluate a patient’s pupils often during the early presentation of the condition to determine if the pupil is becoming mydriatic.Patients who present with ptosis and EOM restriction, but no pupil involvement, are likely suffering from ischemia affecting the 3rd cranial nerve (most commonly due to diabetes).Pupil involvement suggests possible aneurysm or compressive lesion.Can present with mild signs, and pupil involvement may not be seen in early or ischemic cases.Full presentation includes mydriasis, ptosis, and restricted EOM’s often resulting in a “down and out” appearance of the affected eye. ![]() Third nerve palsy, Adie’s Tonic Pupil, and pharmacologic dilation are three common causes of “big pupil” problems. Will dilate the Horner’s pupil as long as the third order pathway is intactĪs opposed to small pupil problems, anisocoria in which the larger pupil is affected will be most exaggerated in bright lighting.To be used only after confirmation testing has been performed.A Horner’s pupil WILL dilate MORE than the normal pupil, reversing the anisocoria.A Horner’s pupil WILL NOT dilate after instillation (normal pupil will).Pharmacologic testing can be used to confirm Horner’s and indicate which part of the pathway has been affected.Typically presents with anisocoria (worse in dim lighting) and mild ptosis the smaller or miotic pupil is the affected pupil.Possible etiology: problem at the internal carotid cavernous sinus problem.Third order is anything beyond the superior cervical ganglion to the pupil dilators and lid.Second order refers to C8-T1 to the superior cervical ganglion.First order refers to the part of the pathway from the hypothalamus to C8-T1.Can be first, second, or third order depending upon which area of the pathway is affected.Interruption in the sympathetic nervous system pathway which controls mydriasis in normal circumstances.Two conditions to keep in mind that can lead to inability to dilate normally/miotic pupils are: 1. ![]()
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