Papilledema

Papilledema (optic disc edema) occurs due to increased intracranial pressure (ICP) from various etiologies. The "papilla" is another word for optic nerve head (the site of entry of the optic nerve into the back of the eye). There are two proposed theories for axoplasmic stasis that results in the optic nerve swelling:

• Mechanical theory - High ICP directly compresses the optic nerve to produce nerve swelling (via axoplasmic stasis).
• Ischemic theory - High ICP results in ischemia to the optic nerve head, which results in axoplasmic stasis and, thus, nerve swelling.

Headache is typically a prominent feature of increased intracranial pressure. The headache severity and quality depends on the underlying etiology. For instance, in idiopathic intracranial hypertension (pseudotumor cerebri), the headache pain, itself, may not be terribly severe but there are other characteristic features (eg, washing machine sound) that accompany the headache. The full symptom complex found in papilledema directly depends on the underlying etiology. For instance, in meningitis-induced increased intracranial pressure, patients can progress to coma (and death); whereas, idiopathic intracranial hypertension can cause severe visual impairment but does not cause coma and is not fatal. Because the papilledema, by definition, begins with expansion of visual “blind spot” (the visual field that references the optic disc), patients are typically unaware of the visual loss until it is fairly severe. Optic disc edema on fundoscopic exam is the definition of papilledema. It's important to know, however, that the development of disc edema can lag behind the development of increased ICP. And, conversely, the disc edema will persist for a period of time after the ICP is brought back to normal. Expansion of the visual blind spot can be detected on visual field testing at the bedside and confirmed with formal visual field testing. For more information on the pathogenesis and complexities of papilledema, see Optic Disc Edema and Elevated Intracranial Pressure (ICP): A Comprehensive Review of Papilledema Papilledema