Recognition of papilledema and the proper interpretation of its etiology falls primarily to the ophthalmologist. The advanced case does not usually get referred to the ophthalmologist since the fundus picture is easily identified. However, such cases do not necessarily suggest the etiology. The diagnosis of minimal disc swelling is made from evaluation of the disc plus a constellation of signs and symptoms.
Fundus Early Signs
Hyperemia - It is caused by capillary dilatation and is more easily seen in young children and old age where the disc tends to be naturally paler.
Venous Distention - In cases other than increased intracranial pressure (IICP) retinal veins may be enlarged because of shunting of blood as occurs in arteriovenous fistula in the orbit or cavernous sinus thrombosis or impending venous occlusion. If venous distention of the disc is due to a fistula, venous dilatation may be seen on the outside of the eye such as in the conjunctiva, episclera and lids.
Blurring of Disc Margin - This is first seen on the nasal border. It is more difficult to identify in a smaller, more crowded hyperopic disc than a larger myopic disc. The small disc of the hyperopic patient tends to be more blurred naturally. If blurring is first noted on the temporal side of the disc, you should consider some local process like a juxtapapillary choroiditis, tumor or vascular process like in anterior ischemic optic neuropathy (AION) or occlusive vascular disease.
Paton's Lines - Vertical lines appear on the temporal side of the disc early in the process of papilledema. They can be easily missed. They are best seen with the direct ophthalmoscope as the examiner moves the light back and forth over the temporal edge of the disc. This highlights the "hills" and "valleys" of the displaced retina. This sign disappears as more edema occurs in that area. These vertical lines are not seen with pseudopapilledema.
Spontaneous Venous Pulse - A spontaneous venous pulse is always normal and signifies no IICP over 200mm, a value which is considered the upper limits of normal. The absence of a spontaneous pulse may or may not be normal. A spontaneous arterial pulse is always abnormal. It means that either the intraocular pressure is too high for the arterial pressure or the arterial pressure is too low such as in severe carotid occlusive disease.
Deflection of Disc Vessels - This is significant only if the vessels are deflected because of disc elevation. It is not an uncommon vascular anomaly for vessels to leave the disc and project into the vitreous cavity before returning to the retinal surface without being displaced by a swollen disc.
Hemorrhages and Exudates - These can be seen with swelling from any cause and are not specific for IICP. Some hemorrhages like Roth spots (hemorrhages with a white center) suggest a specific etiology like subacute endocarditis, lupus erythematosis, leukemia and scurvy.
Exudates in the macular such as a macular star always suggest chronicity.
Change in Vision - Loss of vision with papilledema is usually seen with papillitis or AION. However, prolonged edema from IICP can cause loss of vision and or field and is not uncommon with pseudotumor cerebri.
Optociliary Shunt Vessels - These are an infrequent finding on the disc and classically suggest optic nerve meningioma. However, the more recent association has been due to ischemic blood flow to the disc.
In these early cases all of the above need to be considered in order to make a proper diagnosis of papilledema. You must then put in order your differential diagnosis so that a proper and timely work up can be instituted. IICP is not treated with a follow-up appointment, it demands immediate action.
Increased intracranial pressure can occur without papilledema. This is particularly true in a disc that is already atrophic. An atrophic disc has no axoplasam to back up onto the disc.
Thomas J. Walsh, M.D