Diagnose and Manage Pseudo–Foster Kennedy Syndrome

Ophthalmic Pearls

NEURO

by laura a. vickers, md, m. tariq bhatti, md, and mays a. el-dairi, md edited by sharon fekrat, md, and ingrid u. scott, md, mph

oster Kennedy syndrome 1A 1B was first described in 1911 by the neurologist Robert Foster Kennedy, who char- acterized the disorder as compressionF of one optic nerve by a subfrontal meningioma, resulting in optic nerve head pallor, with increased intracranial pressure causing contralateral optic nerve head edema.1 True Foster Kennedy syndrome is rare, but other causes of unilateral disc edema with contralateral optic pallor are more common. These have 2A 2B been termed pseudo–Foster Kennedy syndrome, or PFK. This review will present a recent case report of PFK and discuss differential diagnosis and management of the condition.

Case Report A 67-year-old woman presented to our institution, complaining of a 30-day history of headache that registered 10 on a 10-point scale of severity and a two-week history of decreased vision PROGRESSION. (1A , 1B) At presentation, the patient’s left optic nerve was swol- in her left eye. Her left optic nerve was len. (2A, 2B) One year later, the optic nerve of her right eye was mildly swollen, swollen (Figs. 1A and 1B), and her and the optic nerve of her left eye was segmentally pale. erythrocyte sedimentation rate (ESR) was 9. Initially, she was started on oral eye was mildly swollen, and the optic poral artery biopsy was performed. prednisone. The swelling of the left nerve of her left eye was pale superi- This demonstrated healing arterial optic nerve resolved in four weeks and orly (Figs. 2A and 2B). At this time, wall inflammation with intimal elastic was replaced by pallor. At the five- her ESR was 20. Because of her well- degeneration. The diagnosis: GCA pre- week mark, when results from a left documented history of unilateral optic senting as PFK. md temporal artery biopsy were normal, nerve head edema replaced by pallor the prednisone was tapered off. in four weeks, neuroimaging was not Diagnosis and Management vickers, One year later, the patient presented performed. However, because of our PFK is a diagnosis of exclusion. When a. with scalp tenderness and jaw clau- persistent high clinical suspicion for a clinician encounters a patient with

laura dication. The optic nerve of her right giant cell arteritis (GCA), a right tem- one swollen and one pale optic nerve,

eyenet 33 Ophthalmic Pearls neuroimaging should routinely be ob- negative temporal artery biopsy on the patients who were initially diagnosed tained, especially if the history is vague more symptomatic side, biopsy of the with bilateral sequential NAION and or not typical for anterior ischemic contralateral temporal artery is rec- later proved to have a compressive le- optic neuropathy (AION). ommended. When a patient presents sion with development of neurologic Bilateral sequential anterior isch- with edema of the contralateral nerve symptoms.5 As a result, clinicians emic optic neuropathies, either arterit- after an initial AION, the diagnosis of should have a very low threshold of ic (AAION) or nonarteritic (NAION), AAION should be reconsidered even suspicion and should order additional are the usual culprits in PFK, with if testing was previously negative.3 testing, including neuroimaging, if NAION the most common etiology. There is a false-negative rate of up to there is any question about the etiol- NAION. This occurs most frequently 5 percent for biopsy of the initially af- ogy of PFK. in middle-aged patients, with men fected side. False-negative results have and women affected equally.2 On ex- been attributed to inadequate length Conclusion amination, the swollen nerve is likely of biopsy specimen, skip lesions, errors The differential diagnosis of the clini- to display hyperemic edema with disc in specimen sectioning, and prebiopsy cal finding of a pale optic nerve with hemorrhage, segmental pallor, and at- treatment with steroids.4 contralateral optic nerve head edema is tenuated blood vessels. ESR, C-reactive broad. Most commonly, PFK is due to protein (CRP), and platelet levels are Uncommon Etiologies bilateral sequential NAION, but clini- normal. PFK also may be observed less com- cians should have a low threshold for Management. In coordination with monly in the following settings. ordering neuroimaging and a labora- the patient’s primary care provider, Retrobulbar neuritis. In this in- tory workup for GCA and for perform- testing and modification of vascular stance, the optic nerve head usually ing an assessment for increased intra- risk factors should be undertaken. No appears normal on examination. How- cranial pressure. n other interventions, including optic ever, bilateral sequential optic neuritis nerve sheath fenestration, steroids, may present with optic nerve head Dr. Vickers is a third-year ophthalmology aspirin, or intravitreal injections of edema in the acutely affected eye. resident, Dr. Bhatti is associate professor of anti–vascular endothelial growth fac- Chronic unilateral optic atrophy. ophthalmology and neurology and director tor medications, have proved effective. PFK may be seen in patients with this of the neuro-ophthalmology service, and Dr. AAION. In cases of AAION, the condition, regardless of its cause, and El-Dairi is assistant professor of ophthalmol- swollen nerve—the one affected more who later present with acute optic ogy; all are at Duke University Eye Center in recently—often displays pallid edema. nerve swelling on the contralateral Durham, N.C. The authors report no related On average, patients with AAION side. Potential etiologies include trau- financial interests. are older, more commonly female, matic optic neuropathy, prior optic and have worse visual outcomes than neuritis, compressive optic neuropa- 1 Kennedy F. Am J Med Sci. 1911;142:355-368. NAAION patients with rare late im- thy, and a history of meningitis. 2 Bhatti MT. How do you evaluate non- provement. These patients commonly Additional etiologies. There are arteritic anterior ischemic optic neuropa- have elevated ESR, CRP, and platelet some rare reports of PFK occurring in thy? In: Lee AG. Curbside Consultation in levels. A 2- to 3-cm temporal artery younger individuals. In these patients, Neuro-Ophthalmology: 45 Clinical Questions. biopsy with pathologic examination of the etiology of PFK may include pachy- Thorofare, N.J.: Slack; 2008. consecutive slices spaced at 0.25 cm is meningitis related to microvasculitis 3 Ischemic Optic Neuropathy Decompression the gold standard for diagnosis. that tests positive for perinuclear Trial. Arch Ophthalmol. 1996;114(11):1366- Management. In all patients older antineutrophil cytoplasmic antibod- 1374. than 50 years of age presenting with ies (p-ANCA), idiopathic intracranial 4 Pless M et al. J Neuroophthalmol. 2000;20 signs of ischemic optic neuropathy, hypertension, or unilateral optic nerve (3):216-218. laboratory testing for GCA should be hypoplasia. Additionally, there are re- 5 Gelwan MJ et al. J Clin Neuroophthalmol. obtained. (This should include a com- ports of patients with increased intra- 1988;8(1):49-52. plete blood count as well as the ESR cranial pressure and papilledema who and CRP tests.) If the patient is also develop unilateral optic atrophy and Got Pearls? complaining of headaches or other thus present with PFK. symptoms of GCA, or if the patient has Write a Pearls article! an abnormal ESR or CRP level, sys- A Note on Follow-up Ophthalmic Pearls, EyeNet Magazine temic steroids should be started imme- Follow-up is essential; the clinician 655 Beach Street diately, and a temporal artery biopsy should observe the affected optic nerve San Francisco, CA 94109 performed within two weeks. for four to eight weeks to be sure that [email protected] When the clinician has persistent the swelling is resolving and is being Writers guidelines provided 2 high clinical suspicion for AAION de- replaced by pallor. upon request. spite negative laboratory testing and a There have been case reports of

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