Examination of the patient with visual loss and unilateral disc swelling

This presentation will show multiple examples of disc swelling and the clues one must use to decide its cause. Several congenital conditions (tilted disc, hypoplasia, disc hamartoma, drusen) have an elevated or even swollen‐looking appearance which may, at first glance, be mistaken for acquired disc edema. Acquired swelling of the optic disc represents axoplasmic stasis due to obstruction of orthograde axoplasmic transport. A variety of insults (compression, ischemia, inflammation, metabolic derangement, toxicity and malignancy) to the proximal portion of the optic nerve can disrupt axoplasmic flow , so disc swelling (edema) is a rather non‐specific finding. It is presence of other accompanying fundus abnormalities which is helpful for distinguishing the mechanism of disc swelling, and these can be divided into disc‐related signs and retinal signs and will be discussed. It is also helpful to examine the contralateral disc. For example, a small or absent cup suggests a structural risk for ischemic injury. Of note, papilledema due to increased intracranial pressure is rarely a cause of unilateral disc edema (less than 5% of cases).