29-year-old obese female with chief complaint of her vision being “foggy on the right side”
Also complaining of chronic frontal headaches and tinnitus
Denies any trauma or new medications
VA: 20/20; 20/20
IOP: 14 /12
Pupils: RR OU, no RAPD
EOM: full, color plates full
Pseudopapilledema (PPE): optic nerve head drusen
True Papilledema (PE):
Idiopathic intracranial hypertension
Intracranial mass lesion
Optic nerve head drusen (ONHD)
ONHD are homogenous, globular concretions within the optic nerve head (1) composed predominately of mucopolysaccharides and proteinaceous material that accumulate anterior to the lamina cribrosa. The primary pathology appears to be an inherited dysplasia of the optic canal or optic disc and its vasculature, impeding normal axonplasmic flow leading to abnormal metabolism with disposition of calcium crystals in mitochondria, which are extruded into the extracellular space. Continuous calcification coalesces to form drusen.
Management goals should focus first on differentiating PPE from true PE
Buried ONHD produce elevation of the disc and blurring of its margin, mimicking optic nerve head edema. Major features differentiating ONHD include: lack of hyperemia, lack of disc surface microvascular abnormalities and visible retinal vessels at the disc margin.
Ancillary testing can aid in differentiating PPE and true PE. Fundus photos, fluorescein angiography (FA), fundus autofluorescence (FAF), B-scan ultrasound, CT scan and OCT can all be used to aid in diagnosis.
FA: true PE may show leakage at the optic disc
AF: hyper-autofluorescence of superficial optic nerve head drusen
B-scan: drusen appear as hyperechogenic masses on the optic nerve head with posterior shadowing
CT scan: drusen appear as areas of increased density at the site of an ONHD
OCT: drusen appear as focal hyperreflective subretinal masses with adjacent retinal elevation
Most patients are asymptomatic. They are monitored with serial visual fields, optic nerve fiber analysis and repeat intraocular pressure measurements.
The evolution of disc drusen is a dynamic process and continues throughout life, (1). During childhood, the affected optic disc appears to become more “full” and acquires a tan or yellowish straw color. The buried drusen gradually impart a scalloped appearance to the margins of the disc and produce subtle excrescences on the disc surface. As they enlarge, they can deflect retinal vessels overlying the disc. In adulthood, the disc elevation diminishes, the disc becomes pale and nerve fiber layer thins. The evolution reflects a slow attrition of the optic axons over decades. The visual prognosis is generally good and patients are observed.
Recent studies hope to identify the most accurate methodology to classify true PE from PPE and analyze misinterpretation rates, (7). Investigators found FA was superior for classifying pediatric eyes as true PE or PPE owing to the existence of leakage as a clear and easily evaluated marker for true edema.
Optic nerve head drusen: Clinical tips
A diagnosis of exclusion
Rule out treatable conditions such as papilledema and glaucoma
Vast majority of patients are asymptomatic
Slow progressive peripheral vision loss over years (inferonasal), enlarged blind spot