The term denotes the noninflammatory passive edema of the optic disk secondary to increased intracranial pressure (ICP) from such causes as intracranial space-occupying lesion (ICSOL) like tumors, obstructive hydrocephalus, intracranial hemorrhage, meningoencephalitis, toxic encephalopathy, conditions with early closure of sutures and fontanel (craniosynostosis) and pseudotumourcerebri.
The disc changes include edematous blurring of the disk margins, fullness of the nerve head, partial or complete obliteration of the physiologic cup, capillary congestion and hyperemia of the nerve head, generalized engorgement of the veins, loss of spontaneous venous pulsation, nerve fiber layer hemorrhages around the disk and peripapillary exudates. Additional features in some cases include extension of edema onto the macula leading to star shaped or fan-shaped figure formation, and concentric peripapillary retinal wrinkling.
Though papilledema resolves following relief of raised ICP, disk takes 6 to 8 weeks to revert to normal. Long-standing papilledema accompanying chronic raised ICP may cause permanent nerve fiber damage, atrophic changes of the disk, nuclear scarring and impairment of vision.
Lumbar puncture in the presence of papilledema must only be done by an expert. Else, it may cause "coning" and death.