Adult Neuro-ophthalmology

Educational Objectives

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

1. Evaluate unexplained visual loss, including consideration of organic and nonorganic etiologies.
2. Enter signs, symptoms, and diagnosis as distinct and separate entities in the medical record.
3. Distinguish clinical features of life-threatening neuro-ophthalmologic diseases.
4. Order the correct diagnostic testing in suspected cases of specific neuro-ophthalmologic diseases.

Summary

Seven steps to evaluate unexplained visual loss: ensure that visual loss is the chief complaint (rather than diplopia or oscillopsia from nystagmus); perform complete examination with no shortcuts (check for relative afferent pupillary defect [RAPD] and perform formal visual field test); look for subtle causes of vision loss before ordering magnetic resonance imaging (MRI); perform a formal automated perimetry test on all patients with unexplained visual loss; history and examination should precede further testing; order specialized tests if indicated, in order from multifocal electroretinography (mfERG), electroretinography, optical coherence tomography (OCT), fluorescein angiography (FA), to neuroimaging; rule out optic neuropathy or hemianopsia; rule out organic etiologies before diagnosing problem as functional (nonorganic) visual loss (FVL)

Assessment: ask patient to describe symptoms, eg, monocular vs binocular, central vs peripheral vision, and presence of diplopia or oscillopsia; expect patients to have difficulty articulating the problem; always test for RAPD and perform formal visual field (VF), color vision (CV) testing; pay particular attention to fundus; perform slit-lamp examination; oil-droplet and posterior subcapsular cataracts are common causes of subtle visual loss (they degrade vision out of proportion to how they appear); if automated VF is deemed unreliable, perform confrontation VF to look for homonymous or bitemporal hemianopsia; refractive error and media opacities rarely produce field defects; any respect of the vertical median is significant; nasal hemianopic field defects are almost always glaucomatous; subtle macular lesions (eg, small macular hole, cystoid macular edema) can be easily missed; use OCT to look for macular structural changes and epiretinal membrane, assess retinal nerve fiber layer, and measure macular ganglion cells; FA is indicated if OCT is negative or choroidal perfusion deficits are suspected; otherwise, OCT has essentially supplanted FA; large blind spots, ring scotomas, photopsia, hemeralopia, and nyctalopia suggest a retinal problem; look for diffuse retinal arterial narrowing, which is present in diffuse retinal disease; if an enlarged blind spot is present but the fundus appears normal, perform ERG to confirm problem is with retina; enlarged blind spot is also associated with papilledema; cone dystrophy causes central visual loss and can be confirmed with mfERG; optic neuropathy can cause CV loss, RAPD in unilateral cases, abnormal OCT of optic nerve or macula, disk pallor or edema, and VF defects; large blind spot points to retina problem; before a problem is diagnosed as functional or nonorganic, every effort should be made to provide proof

Questions and answers: disorders ofhigher cortical function — in audience member’s clinic, it is the most common cause of unexplained visual loss in elderly patients; tip-offs include the patient being brought in by spouse, patient having no chief complaint, and patient reporting reading difficulty; screening for FVL — the field defect most widely relied upon is the constricted field; in FVL, constricted VF will not expand with increased test distance (ie, tunnel field); in cases of organic visual loss, VF does expand with distance (ie, funnel field); confrontation VF may be used

Pearls of neuro-ophthalmology: keep signs, symptoms, and diagnosis distinctly separated in the record; ensure that all medical records are clean and thorough (do not allow “sewage” to pollute record); having a differential diagnosis is mandatory; follow standardized neuro-ophthalmology rules; either perform workup or refer the patient to neuro-ophthalmology in a timely manner after triaging; the patient’s chief complaint must be addressed, even if examination is normal; impression and diagnosis must not be written as “normal examination”; signs, symptoms, and diagnosis must be indicated correctly on the chart, eg, diplopia is a symptom, not a sign or diagnosis; ptosis is a sign, not a diagnosis; the etiology must be addressed (eg, ptosis secondary to levator dehiscence and without neuro-ophthalmologic etiology); even if the chief complaint is unilateral, both eyes must be examined; cancer history — if patient has past medical history of cancer, include stage, grade, and treatment; do not simply write “lung cancer”; advanced stages of cancer are far more likely to cause ocular complications than previously treated low-grade disease

Pupil testing: the acronym PERRLA (pupils equal, round, and reactive to light and accommodation) is inadequate; it only addresses 1 of 3 areas the clinician needs to check during a pupillary response examination; PERRLA test only assesses the parasympathetic pathway, not the sympathetic pathway or for an RAPD; PERRLA test also does not check for anisocoria in the dark, which is a feature of Horner syndrome; an RAPD can be present even if a PERRLA test is normal; speaker’s recommendation — record the size of pupils in dark and light along with positive or negative RAPD

Horner syndrome: apraclonidine is useful for differentiating between physiologic anisocoria and Horner syndrome; dissection of the internal carotid artery must be considered in acute Horner syndrome; features include neck pain, transient vision loss, branch or central retinal artery occlusion, and dysgeusia from involvement of the chorda tympani; imaging of the neck should be ordered, along with the entire sympathetic pathway; the sympathetic pathway extends from the hypothalamus, descends the posterior lateral brainstem, exits the white rami communicantes, travels over the apex of the lung to the carotid artery, then to the superior cervical ganglion, back to the carotid artery, to the cavernous sinus, on to cranial nerves VI and V, then to the target organ; imaging should extend down to thoracic nerve T2; in carotid dissections, the crescent sign refers to the hyperintense signal surrounding the carotid artery flow void; most carotid dissections occur in the neck; Horner syndrome is also associated with Pancoast tumors (in the apex of the lung); fatalities in Horner syndrome often result from carotid dissection or Pancoast tumors

Ischemic optic neuropathy (ION) vs optic neuritis (ON): must indicate etiology of ION in record (“ischemic optic neuropathy” is not an etiologic diagnosis); moreover, anterior ION (AION) includes arteritic and nonarteritic forms; the speaker notes that there is no such entity as “ischemic optic neuritis”; in elderly patients, arteritic AION secondary to giant cell arteritis (GCA) is much more likely than ON; similarly, “retrobulbar ON” in elderly patients could actually be posterior ION (PION) but is much more likely to be GCA; pallid disk edema is almost exclusively associated with GCA; FA must be performed in all elderly patients with retrobulbar optic neuropathy to look for choroidal perfusion deficit; ON can be demyelinating or idiopathic and is more common in younger patients; elderly patients are much more likely to have PION

Questions and answers: esotropia in pediatric patients — esotropia is not a diagnosis; must indicate the etiology in the record (eg, secondary to myasthenia gravis); perfectly acceptable to use “idiopathic” as a diagnosis when necessary

Potentially life-threatening conditions: include arteritis, apoplexy of the pituitary gland, abscess secondary to fungal infection (particularly from Mucor species), aneurysm of the posterior communicating artery (PCOM) presenting with a third nerve palsy, and arterial dissection of the carotid or vertebral artery

Giant cell arteritis: acute unilateral loss of vision with RAPD, normal fundus, and pain upon eye movement is more likely to be ON in a young patient and GCA in an elderly patient; RAPD and normal fundus indicate a retrobulbar problem in elderly patient (tumor, apoplexy, GCA); an MRI should be ordered, but it appears normal in GCA; if GCA is suspected, always perform FA regardless of presence of pallid disk edema; OCT will not be helpful; GCA can cause bilateral severe vision loss (eg, light perception only or no light perception), amaurosis fugax, or transient diplopia; these findings are not present in nonarteritic AION; polymyalgia rheumatica (PMR) is associated with GCA; PMR causes proximal shoulder and hip girdle pain and morning stiffness; ask if patient has difficulty or pain combing their hair, rising from a chair, or climbing stairs

Pituitary apoplexy: signs include acute onset, severe headache, and bitemporal hemianopsia; abnormally low cortisol levels are fatal in 8% of cases; distinctive radiographic features include a rim of hyperintense signal surrounding a hypointense core; Semple et al found that the average age of patients with pituitary apoplexy is 51 yr; average time of presentation is 14 days after the ictus; 81% of cases do not have a history of pituitary tumor; 56% of cases involve loss of visual acuity; 34% of cases have bitemporal hemianopsia, meaning that they require a VF test; 73% have panhypopituitarism; 8% of cases have diabetes insipidus; must perform confrontation field test

Fungal orbital cellulitis: case study — patient on day 14 of induction chemotherapy presented with puffy eyelids and puffy eyes; the patient was afebrile and neutropenic, with erythema and chemosis; computed tomography revealed pansinusitis, and orbital studies showed nonspecific fat stranding consistent with orbital cellulitis; the patient was started on vancomycin and ceftriaxone but did not improve; resident physician hypothesized idiopathic orbital inflammatory pseudotumor; the speaker identified the problem as Mucor infection; orbital inflammatory pseudotumor is an immune-mediated process (as is the rare Tolosa-Hunt syndrome) and therefore cannot occur in immunosuppressed patients; this patient had an infection; steroids should be avoided; biopsy from the nose was positive for fungal hyphae with angioinvasion; radiographic features included enhancement of the sphenoid sinus and optic nerve (from retrobulbar optic neuropathy); imaging of the orbital apex must be ordered with contrast and fat suppression

Third nerve palsy: the “rule of the pupil” states that a pupil-involved third nerve palsy must be considered an aneurysm of the PCOM until proven otherwise; angiography must be ordered to detect the aneurysm; do not rely on MRI

Arterial dissection: if acute Horner syndrome is suspected, testing with apraclonidine or cocaine drops may be omitted, as there is greater urgency for imaging to detect possible carotid dissection; imaging of the entire sympathetic axis must be performed; in arterial dissections, a plaque can enter the retina to cause a central retinal artery occlusion (cherry-red spot) or enter the brain to cause a stroke; carotid dissections require antiplatelet therapy and admission; acute homonymous hemianopsia may indicate dissection of the vertebral artery

Readings

Bruce BB, Newman NJ. Functional visual loss. Neurol Clin. 2010 Aug;28(3):789-802; Farooq AV et al. Fungal orbital cellulitis: presenting features, management and outcomes at a referral center. Orbit. 2015 Jun;34(3):152-159; Lee AG et al. Atypical features prompting neuroimaging in acute optic neuropathy in adults. Can J Ophthalmol. 2000 Oct;35(6):325-330; Lee AG et al. Imaging for neuro-ophthalmic and orbital disease - a review. Clin Exp Ophthalmol. 2009 Jan;37(1):30-53; Lee HJ et al. Oil droplet cataract: cause of decreased vision of unknown etiology. J Korean Ophthalmol Soc. 2016 Jun;57(6):963-968; Lemos J, Eggenberger E. Neuro-ophthalmological emergencies. Neurohospitalist. 2015 Oct;5(4):223-233; Levin LA. The perils of PERRLA. Ann Intern Med. 2007 Apr;146(8):615-616; Sano T et al. Retrobulbar optic neuropathy associated with sphenoid sinus mucormycosis. Neurol Clin Neurosci. 2018 Sep;6(5):146-147; Semple PL et al. Pituitary apoplexy. Neurosurgery. 2005;56(1):65-73; Song JX et al. Ocular manifestations of internal carotid artery dissection. Int J Ophthalmol. 2019;12(5):834-839; Vodopivec I, Rizzo JF III. Ophthalmic manifestations of giant cell arteritis. Rheumatology (Oxford). 2018 Feb;57(suppl_2):ii63-ii72; Volpe NJ et al. Acute idiopathic blind spot enlargement syndrome: a review of 27 new cases. Arch Ophthalmol. 2001 Jan;119(1):59-63.

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, members of the faculty and planning committee reported nothing to disclose.

Acknowledgements

Dr. Lee spoke at the 43rd UOS Annual Physician Conference, presented by the Utah Ophthalmology Society and held February 26, 2021. For information about upcoming CME conferences from this sponsor, please visit utaheyemds.org. 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:

OP591801

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.