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A 25-year-old Caucasian female is sent to you for evaluation because of a “funny looking optic nerve”.

1.	What is in your differential diagnosis for this patient?
	a -- intra-cranial mass If you look at the vessels overlying the optic nerve, you will notice that the optic nerves are both elevated.  Automatically, papilledema versus pseudopapilledema should fall on your differential.  When there is bilateral disc edema, you need to rule out an intracranial tumor as the possible etiology.  There is no optic nerve pit or morning glory disc anomaly present and the cup to disc ratio appears normal.
2.	What characteristics help you differentiate between papilledema and pseudopapilledema?
	d -- all of the above These are pictures of pseudopapilledema caused by bilateral optic disc drusen (ODD).  Many factors can help you differentiate between papilledema and pseudopapilledema in this case.  Not only is there a lack of hyperemia, but also the retinal vessels at the optic nerve margin are distinct and not blurred or obscured.  Sometimes you will see an anomalous retinal vascular pattern (e.g. vascular loops, increased vascular tortuosity or increased vascular branching) associated with ODD.  Also, unlike in papilledema there are not any abnormalities of the disc surface microvasculature (e.g. capillary dilation and flame-shaped hemorrhages) present here.
3.	What tests could help you differentiate pseudopapilledema secondary to optic disc drusen from papilledema?
	e -- (a), (b) and (c) Many ancillary tests can help you differentiate optic disc drusen (ODD) from papilledema.  If the drusen has calcified, it would be highly reflective on B-scan ultrasonography and remain highly reflective even when the signal intensity is decreased.  Also, a computed tomography (CT) scan (not MRI) would be able to easily pick up the calcium.  On FA, ODD usually shows areas of focal blockage early in the angiogram and late staining without leakage, whereas papilledema will have early hyperflourescence and late leakage.  In addition, ODD may show autoflourescence if they are more superficial.