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Ophthalmology > OPTIC NERVE
Pseudopapilledema
Article Last Updated: Jul 1, 2005
AUTHOR AND EDITOR INFORMATION
Section 1 of 10  
Author: Joseph Giovannini, MD, Chief of Ophthalmology, Eye Surgery Center, David Grant Medical Center, Travis AFB, California
Joseph Giovannini is a member of the following medical societies: American Academy of Ophthalmology and American Society of Cataract and Refractive Surgery
Coauthor(s):
Georgia Chrousos, MD, Clinical Professor, Department of Ophthalmology, Division of Neuro-Ophthalmology and Pediatric Ophthalmology Services, Georgetown University Medical Center
Editors: Edsel Ing, MD, FRCSC, Assistant Professor, Department of Ophthalmology & Vision Sciences, University of Toronto: Consulting Staff, Toronto East General Hospital; Donald S Fong, MD, MPH, Assistant Clinical Professor of Ophthalmology, Director, Clinical Trials Research, Department of Ophthalmology, Southern California Permanente Medical Group; Brian R Younge, MD, Professor of Ophthalmology, Mayo Clinic School of Medicine; Lance L Brown, OD, MD, Ophthalmologist, Affiliated With Freeman Hospital and St John's Hospital, Regional Eye Center, Joplin, Missouri; Hampton Roy Sr, MD, Associate Clinical Professor, Department of Ophthalmology, University of Arkansas for Medical Sciences
Author and Editor Disclosure
Synonyms and related keywords:
papilledema, optic disc drusen, optic disc swelling
Background
While papilledema is disc edema secondary to increased intracranial pressure, pseudopapilledema is apparent optic disc swelling that simulates papilledema but is usually secondary to an underlying benign process.
Most patients with pseudopapilledema lack visual symptoms, not unlike patients with true papilledema. In pseudopapilledema, no obscuration of the peripapillary vessels by the nerve fiber layer edema occurs. Pseudopapilledema may be unilateral or bilateral, but almost all cases of papilledema are bilateral. An extensive workup is usually unnecessary, and an experienced ophthalmologist can correctly diagnose pseudopapilledema via an ophthalmoscopic examination.
Pathophysiology
There are a multitude of causes of true disc swelling and other disorders that may mimic disc swelling. These cases can 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). The optic cup may be smaller than usual in a hyperopic eye. This causes crowding of the axons, which become elevated as they leave the eye. The nerve fiber layer, which is normally 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 and, sometimes, a loss of vision. 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 can almost always distinguish these entities.
Other inflammatory, infiltrative, and infectious conditions can cause true disc edema. In these cases, the swelling is almost always 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, diabetes, sarcoidosis, and leukemic infiltration. These conditions should be seen as causes of papillitis, which is a distinct entity apart from pseudopapilledema.
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 loss and, in rare cases, blindness. However, congenital causes are not associated with any progressive visual loss.
Race
Disc drusen are more common in Caucasians 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.
History
Most patients are asymptomatic. No visual symptoms are usually present.
- Visual field loss: In many patients with disc drusen, visual field defects eventually develop, although patients usually remain symptom free.
- Transient visual obscurations
- A minority of patients with disc drusen experience transient visual flickering or graying out that is similar to transient visual obscurations that are sometimes seen in patients with papilledema.
- Rarely, patients might experience permanent visual loss from secondary processes. For example, disc drusen may increase the risk of later developing subretinal neovascular membranes or retinal vascular occlusion.
- Visual acuity: Patients with disc drusen may eventually lose central acuity. Although unusual, this visual loss would most likely follow a long period of gradual field constriction.
Physical
- Evaluate for neurologic problems, hypertension, and febrile illness during both the history and the physical examination.
- Perform visual acuity, color vision, and pupillary examinations. If present, document a relative afferent pupillary defect.
- Perform a careful dilated fundus examination, looking for the following signs:
- Edema of the nerve fiber layer that blurs the disc margins and the peripapillary vasculature is a hallmark of true papilledema. Usually, the peripapillary vessels are clearly seen in pseudopapilledema, except in such cases as myelinated nerve fibers.
- The angle of the optic nerve head should be noted. A tilted disc results from an optic nerve that enters the eye at a sharply oblique angle; it usually has a characteristic appearance of a prominently elevated nasal aspect with a poorly defined or sunken temporal aspect. Patients with tilted discs may have marked astigmatism.
- Other anatomical variants include persistent hyaloid remnants, gliosis of the optic nerve head, and myelination of the nerve fiber layer. These entities have a characteristic appearance on dilated fundus examination.
- When superficial drusen (small, white-to-yellow, granular bulgings of the substance of the disc) are present, they greatly aid in the diagnosis. At other times, drusen can be deeply buried in the substance of the nerve, and the clinical diagnosis is more subtle.
- In papilledema, the disc is usually hyperemic, and an increased frequency of hemorrhages and cotton-wool spots exists. Also, Paton lines and optociliary shunt vessels may be seen with retention of the central cup until late in course of the disease.
- In pseudopapilledema, the disc is yellow, the cup may be small or absent, venous congestion is not present, spontaneous venous pulsations are often present, congenitally anomalous vessels may be seen, and the disc abnormality may be familial.
Causes
- Congenitally anomalous disc
- Hyperopia
- Optic disc drusen
- Tilted disc
- Myelinated nerve fiber layer
Idiopathic Intracranial Hypertension
Optic Neuritis, Adult
Optic Neuritis, Childhood
Optic Neuropathy, Anterior Ischemic
Optic Neuropathy, Compressive
Papilledema
Sarcoidosis
Scleritis
Toxoplasmosis
Uveitis, Classification
Other Problems to be Considered
Toxic optic neuropathy
Optic disc infiltrates
Papillitis
Leber hereditary optic neuropathy
Orbital and other optic nerve tumors
Diabetic papillitis
Lab Studies
- Laboratory studies are not usually necessary in the workup of patients with disc drusen.
- In patients with suspected Leber hereditary optic neuropathy, mitochondrial mutations are helpful.
Imaging Studies
- B-scan ultrasonography may be useful in identifying buried disc drusen. Because drusen are calcified, they demonstrate high reflectivity on ultrasound.
- While rarely indicated, a CT scan may show small areas of calcification within the disc substance, which represent calcified disc drusen. Progressive field loss in patients with disc drusen merits a CT scan to rule out occult CNS lesions.
- Fluorescein angiography can be used to rule out true papilledema, which exhibits increased dilation of the peripapillary capillaries with late dye leakage.
- Disc drusen may autofluoresce on fluorescein angiography, which can be seen with red-free photo techniques, using the appropriate filters. (Buried disc drusen do not autofluoresce.)
- In Leber hereditary optic neuropathy, disc leakage is not seen on fluorescein angiography.
Other Tests
- Visual field tests should be considered, especially if optic nerve drusen are suspected. Constriction of the visual field can gradually occur; patients rarely have progressive field loss that is insidious or rapid.
- Stereo color photographs of the optic discs are useful to document changes.
Procedures
- No additional procedures are indicated.
Medical Care
- No treatment is needed for most causes of pseudopapilledema because they represent normal physiologic variants.
- A minority of patients with disc drusen (16-22%) present with progressive visual loss. Field deterioration normally occurs over many years and is generally slow and unnoticed by patients. Dramatic field loss related to vascular complications, such as anterior ischemic optic neuropathy, can rarely occur. Unfortunately, no successful therapy is available at this time.
Surgical Care
No effective surgical treatment is available.
Complications
- With disc drusen, gradual loss of the peripheral visual field may occur and, rarely, loss of central vision.
Prognosis
- The visual prognosis is generally good.
Medical/Legal Pitfalls
- Progressive field loss in patients with disc drusen merits a CT scan to rule out occult CNS lesions.
| Media file 1:
Superficial optic nerve drusen. Note the irregular disc margins with preserved vascular and perivascular detail. |
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Media type: Image
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Pseudopapilledema excerpt Article Last Updated: Jul 1, 2005
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