Papilledema can represent an acute, severe, and life-threatening disease. When presented with this physical examination finding in the ED, it is not to be taken lightly. However, the exact etiology should be elicited to determine the cause of the optic nerve swelling and its subsequent treatment.
The initial differential diagnosis of a patient with papilledema includes etiologies from either increased intracranial pressure or from optic disc swelling. Increased pressure could result from a space-occupying lesion (e.g. brain tumor, abscess), idiopathic intracranial hypertension, subdural hematoma, meningitis, cerebral edema from trauma, or hydrocephalus. Optic disc swelling itself can cause papilledema from optic neuritis, uveitis, or even be mimicked with such conditions as scleritis or congenital lesions.
Optic nerve head drusen is a calcified lesion that is congenital, originating as a mucoprotein matrix that progressively calcifies over time on the optic nerve itself. The prevalence of drusen is estimated around 0.34%, but is around 3.4% in individuals with affected family members . Drusen themselves are generally considered benign. However, there are some associated complications, the most common being peripheral visual field defects occurring in approximately 75% of patients . Central retinal artery occlusion, central vision loss, and anterior ischemic optic neuropathy are also rare potential complications . Certain conditions have been associated with optic nerve drusen, including retinitis pigmentosa, angioid streaks, and Usher’s syndrome .
There is no definitive treatment for this disorder. However, affected patients should be followed by an ophthalmologist for serial visual field examinations, optic nerve fiber analysis, and repeat intraocular pressure checks. If visual field loss occurs in the presence of drusen, medication to lower the intraocular pressure should be considered . Laser photocoagulation should only be considered in those cases where central visual acuity is threatened .
Optic nerve head drusen clinically manifests as pseudo-papilledema secondary to the calcified lesion elevating a portion of the nerve head and thus mimicking papilledema on fundoscopic examination. Traditionally, drusen is diagnosed with B mode ultrasonography , which is easily obtained in the ED.
The sonographic differential diagnosis of echogenic structures at the optic disc includes tumors, such as retinoblastoma, retinal detachment, and posterior vitreous hemorrhage.