Papilledema: its recognition and relation to increased intracranial pressure.

This has been a review on the subject of papilledema from a clinical, pathologic and experimental point of view. Terminology has been clarified. The term papilledema should be reserved for those patients with optic disc edema caused by increased intracranial pressure. The forms of papilledema which are identifiable are: 1. Early (incipient) form which develops into an acute type and then into a fully developed form; 2. Fully developed form, characterized by obscured disc margins, hemorrhages and ischemic infarcts; 3. Chronic papilledema which may persist (the name "vintage" papilledema may be applied to those patients affected in varying degrees up to several years); and 4. Chronic atrophic papilledema which, as the name implies, illustrates a form we do not see as frequently as in years past. It is the type we are now trying to prevent and in this effort we are fortunately achieveing some success. The importance of the intracranial expanding lesions and the influence of the rapidity of elevation and duration of intracranial hypertension on the optic nerve has been considered, based on the clinical and experimental work to date. The pathogenesis of papilledema has been considered in some detail. A unified whole is difficult to arrive at in such a complex situation. Recent advances in our understanding of anatomic, mechanical (sheath space pressure), tissue and vascular pressure as related to increased intracranial pressure have been described. A hydrostatic mechanism brings these factors together in a reasonable, although admittedly not completely proven concept of a mechanism for the development of papilledema. Clarification of terminology and clinical appearance of the various forms of disc edema related to intracranial pressure are of practical value in the diagnosis and management of each patient we see with this clinical entity.