Evaluating the Swollen Optic Disk

Educational Objectives

The goal of this program is to improve the management of papilledema. After hearing and assimilating this program, the clinician will be better able to:

1. Differentiate between papilledema and other abnormalities of the optic disk.
2. Describe the processes that lead to elevated intracranial pressure.

Summary

True optic disk edema (papilledema): symptoms of elevated intracranial pressure (ICP) include positional headache (worsened by supine positioning or Valsalva maneuver), transient visual obscuration (generally in both eyes and lasting for seconds), pulse synchronous tinnitus, and binocular horizontal diplopia; swelling of the nerve fiber layer (NFL) can obscure blood vessels; in contrast, vessels course over what appears to be a swollen optic disk in congenital anomalies; shunt vessels or telangiectasias may develop secondarily to congestion of the optic nerve; flame-shaped hemorrhage is a sign of acute elevated ICP; Paton folds (in the NFL) and refractile bodies also indicate papilledema; choroidal folds result from posterior pressure on the globe

Imaging: the Optic Disc Drusen Studies Consortium found that enhanced depth imaging optical coherence tomography (EDI-OCT) can help differentiate between papilledema and pseudopapilledema associated with optic disk drusen; in adults, disk drusen have a hyporeflective core with hyperreflective margin (less applicable in children, as drusen tend to be less calcified); Chang et al found that presence of leakage on fluorescein angiography has the highest accuracy for distinguishing between papilledema and pseudopapilledema, compared with other imaging modalities; a Korean study found that nasal retinal NFL thickness on OCT of <78 μm is suggestive of disk drusen rather than papilledema; autofluorescence can aid in detection of buried disk drusen

Clinical features: a scalloped disk margin and increased vessel branching are associated with disk drusen; no blood vessel obscuration occurs in pseudopapilledema; in congenital disk anomalies, both arteries and veins are tortuous, as opposed to only the arteries in papilledema; cup obliteration is a late-stage finding of papilledema; with congenital disk anomalies, findings are not expected to change over time

Diagnosis: order magnetic resonance imaging of brain and orbit, with and without contrast, to rule out a space-occupying lesion; order magnetic resonance venography to rule out cerebral venous thrombosis; order lumbar puncture to measure opening pressure and rule out inflammatory, infectious, and neoplastic etiologies; if ICP is elevated but all other tests are normal, patient is diagnosed with idiopathic intracranial hypertension (IIH); clinical pearls — papilledema can be asymmetric between the eyes; patients >50 yr of age can have IIH; rule out spinal tumors, particularly in atypical presentations of IIH; optic disk drusen and papilledema can be concurrent

Cerebrospinal fluid (CSF) and ICP: similar to glaucoma, elevated ICP is a problem of decreased drainage of CSF, not of excessive CSF production; 3 pathways of CSF drainage from the brain — studies suggest that the avascular arachnoid granulation pathway is not the source of elevated ICP; the glymphatic system clears toxins from the brain, is mediated by astrocytes, and is vulnerable to metabolic hormones (eg, estrogen); estrogen causes remodeling of connections in this pathway, impeding CSF flow and increasing ICP; >90% of patients with IIH have narrowing of transverse sinus; meningeal lymphatic vessels drain directly from subarachnoid space; if these vessels cannot compensate for decreased flow through the glymphatic system, increased pressure can occur, particularly around the cranial nerves; risk factors for IIH include sleep apnea, weight gain, and elevated vitamin A

Therapies: studies show that weight loss of 6% to 10% is sufficient to cause remission of IIH; weight loss alone is adequate for mild cases with few to no symptoms; if mild visual field changes (eg, enlarged blind spot) are present, diuretics may be prescribed; the IIH Treatment Trial found that ≤4 g of acetazolamide is safe in patients with IIH

Readings

Amador-Patarroyo MJ et al. Congenital anomalies of the optic nerve. Saudi J Ophthalmol. 2015 Jan-Mar;29(1):32-38; Chang MY et al. Accuracy of diagnostic imaging modalities for classifying pediatric eyes as papilledema versus pseudopapilledema. Ophthalmology. 2017 Dec;124(12):1839-1848; Chen J and Wall M. Epidemiology and risk factors for idiopathic intracranial hypertension. Int Ophthalmol Clin. 2014;54(1):1-11; Hayreh SS. Pathogenesis of optic disc edema in raised intracranial pressure. Prog Retin Eye Res. 2016 Jan;50:108-144; Malmqvist L et al. The Optic Disc Drusen Studies Consortium recommendations for diagnosis of optic disc drusen using optical coherence tomography. J Neuroophthalmol. 2018 Sep;38(3):299-307; Smith SV and Friedman DI. The Idiopathic Intracranial Hypertension Treatment Trial: a review of the outcomes [published correction appears in Headache. 2018 Nov;58(10):1697]. Headache. 2017 Sep;57(8):1303-1310.

Disclosures

In adherence to ACCME Standards for Commercial Support, Audio Digest requires all faculty and members of the planning committee to disclose relevant financial relationships within the past 12 months that might create any personal conflicts of interest. Any identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a proprietary business or commercial interest. For this program, the following has been disclosed: Dr. Gokoffski reported nothing to disclose. The planning committee reported nothing to disclose.

Acknowledgements

Dr. Gokoffski spoke at the University of Southern California (USC) Department of Ophthalmology 45th Annual Symposium, held June 12, 2021, and presented by the USC Roski Eye Institute and USC Office of Continuing Medical Education at the Keck School of Medicine of USC. For information about upcoming CME conferences from this presenter, please visit keck.usc.edu/cme. Audio Digest thanks the speakers and meeting presenters for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0 CE contact hours.

Lecture ID:

OP591901

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.