Optic Disc Drusen (Pseudopapilledema)

Updated: Feb 23, 2024
  • Author: Mitchell V Gossman, MD; Chief Editor: Hampton Roy, Sr, MD  more...
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Overview

Background

Pseudopapilledema is the term used to descibe the appearce of a swollen optic dics but does not represent true optic nerve edema. [1] This is in contrast to papilledema which is actual edema of the optic nerve that is caused specifically by an increase in intracranial pressure. [2] Although pseudopapilledema can simulate some of the features of papilledema, it usually is caused by a more benign process, most commonly optic disc drusen.

Most patients with pseudopapilledema lack visual symptoms, not unlike patients with true papilledema. In pseudopapilledema, no obscuration of the peripapillary vasculature occurs because there is no nerve fiber layer edema. Pseudopapilledema may be unilateral or bilateral, but almost all cases of papilledema are bilateral. An extensive workup usually is unnecessary, and an experienced general ophthalmologist or neuro-ophthalmologist can correctly diagnose pseudopapilledema via an ophthalmoscopic examination.

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Pathophysiology

There are a multitude of causes of true disc swelling and other disorders that may mimic disc swelling, some of which represent a morphologic variant of normal.

The optic nerve may be elevated, simply because the optic nerve enters the eye at an extremely oblique angle (tilted disc), giving a portion a more elevated aspect (usually nasally).

The optic cup may be smaller than usual in a hyperopic eye. This causes crowding of the axons, which become heaped-up and elevated as they leave the eye.

The nerve fiber layer, which normally is translucent, may be partially myelinated. This can lead to the appearance of a large cup with blurring of the disc margins.

A subtler (but common) cause of pseudopapilledema is buried disc drusen. This article focuses primarily on optic disc drusen. Disc drusen are composed of small conglomerates of mucopolysaccharides and proteinaceous material that become calcified with advancing age. These small tumors develop within the substance of the nerve tissue (bilateral in 70% of cases) and can lead to an elevated disc; they also may lead to a loss of visual field or, in rare cases, central acuity. [3] They may be inherited as an autosomal trait with irregular penetrance. Disc drusen may be associated with retinitis pigmentosa and pseudoxanthoma elasticum.

Rarely, pseudopapilledema may be caused by remnants of the congenital hyaloid system and localized gliosis. An experienced observer almost always can distinguish these entities.

Primary and metastatic optic nerve tumors can result in a swollen disc but ordinarily only when intraorbital disease is present and is seldom unaccompanied by other signs and symptoms of orbital disease, such as proptosis and motility disturbance.

Papillitis is true disc edema that can be caused by a variaty of inflammatory, infiltrative, and infectious conditions. In these cases, the swelling is usually unilateral (with the major exception of hypertensive crisis). Examples of infectious causes include syphilis, Lyme disease, and cat scratch disease. Examples of inflammatory disorders that cause true disc edema include anterior ischemic optic neuropathy, optic neuritis, diabetes, sarcoidosis, and leukemic infiltration.

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Epidemiology

Frequency

United States

This condition affects 2-5% of the population. It is clinically apparent in only about 0.35% of individuals.

Mortality/Morbidity

Optic disc drusen may be associated with progressive visual field loss, more rarely loss of central acuity, and, in very rare cases, blindness. However, congenital causes are not associated with any progressive visual loss.

Race

Disc drusen are more common in whites and are believed to be less common in African Americans.

Sex

No sexual predilection exists.

Age

The condition occurs at any age, although disc drusen tend to enlarge with time and become more prominent with advancing age.

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Prognosis

The visual prognosis generally is good but there can be rare cases of progressive visual field loss.

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