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Show !oumal of Clill;cal Neuro-ophtl.almology 7(3): 167-169, 1987. ,~, 1987 Raven Press, Ltd., New York Unilateral Syphilitic Optic Perineuritis Presenting as the Big Blind Spot Syndrome John McBurney, M.D., and Michael L. Rosenberg, M.D. Unilateral swelling of the optic nerve head in the absence of demonstrable optic nerve dysfunction (the big blind spot syndrome) has been described as an idiopathic self-limited phenomena. We report two patients who manifested this syndrome due to syphilitic optic perineuritis. Although unilateral syphilitic optic neuritis has been well described, optic perineuritis has been described preViously only as a bilateral condition. The cases emphasize the need to consider syphilis in conditions affecting the optic nerve either unilaterally or bilaterally with or without an associated optic neuropathy. Key Words: Syphilis-Neurosyphilis-Optic perineuritis. From Neuro-ophthalmology Division, Departments of Neurology and Surgery (M.L.R.), Uniformed Services University of the Health Services, Bethesda, MD, and Neurology Service, Walter Reed Army Medical Center, Washington, DC, and Uniformed Services University of the Health Sciences (J.McB.), Bethesda, MD. The opinions or assertions contained herein are the private ones of the authors and are not to be construed as official or reflecting the view of the Department of Defense or the Uniformed Services University of the Health Sciences. Address correspondence and reprint requests to Michael L. Rosenberg, Neuro-ophthalmology Division, Departments of Neurology and Surgery, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Rd., Bethesda, MD, U.S.A. 167 The big blind spot syndrome is a disorder that presents as unilateral optic disc edema without evidence of optic nerve dysfunction in otherwise healthy young adults (1,2). Syphilitic perioptic neuritis has not been previously considered strongly in the differential diagnosis of patients with the big blind spot syndrome, however, because all cases reported to date have been bilateral (3-5). We describe two patients with unilateral optic perineuritis due to syphilis that resolved with antibiotic therapy. The cases emphasize the importance of considering syphilis in the differential diagnosis of all patients with optic nerve head swelling with or without evidence of an optic neuropathy. CASE REPORTS Case 1 A 47-year-old male with known chronic active hepatitis presented with a 3-week history of intermittent abdominal pain and distention, diffuse arthralgias, and headache. Past history was significant only for a "nonspecific proctitis" 3 years prior to admission. He was referred for evaluation of asymptomatic unilateral swelling of the optic disk on the left. Examination revealed right eye 20/20 and left eye 20/20. General physical examination showed severe optic disc swelling on the left with the right being normal. Pupils were normal in size and reactivity with no evidence of an afferent pupillary defect. Visual fields showed an enlarged blind spot on the left with normal fields on the right. Pattern reversal visual evoked potentials were normal and symmetric. The vitreous was clear. Peripheral VORL and FTA-ABS were both positive. A lumbar puncture revealed a normal opening pressure. The cerebrospinal fluid protein was 99 mg% and the glucose was 56 mg%. 168 J. McBURNEY AND M. L. ROSENBERG There were 45 cells, and 50% were mononuclear cells. Cerebrospinal fluid VORL was nonreactive. The patient was treated with 24 million units of aqueous penicillin for 10 days with prompt resolution of all of his symptoms and the rectal and optic nerve findings. A repeat cerebrospinal fluid cell count showed 4 mononuclear cells and protein of 66 mg %. Case 2 A 22-year-old male without prior history of systemic or ocular complaints presented for the evaluation of transient spells of visual blurring occurred only in the right eye. They lasted from 5 to 50 s and recurred 4-6 times per day. Examination revealed 20/15 + visual acuity in each eye. Pupils were of normal size and reactivity with no afferent pupillary defect. Color vision was normal in each eye. Visual fields showed an enlarged blind spot in the right eye but was normal on the left. Funduscopic examination revealed marked disk swelling on the right with a normal disc on the left. There were no cells in the vitreous or anterior chamber. The CT scan and visual evoked responses were both normal. Peripheral VORL and FTA-ABS were positive. Lumbar puncture revealed normal opening pressure with a protein of 75 mg %. There were 30 cells, and 75% were mononuclear cells. VORL done on the cerebrospinal fluid was also positive. He was given 24 million units of aqueous penicillin daily for 10 days with resolution of visual symptoms and disc edema over the next 6 weeks. DISCUSSION Papillophlebitis originally described by Conn and Hoyt (6) and the "big blind spot syndrome" as described by Miller (1) are both clinical syndromes of unilateral optic disc edema without visual loss or increased intracranial pressure. Here we present two cases that closely resemble these syndromes due to unilateral optic perineuritis caused by infection with treponema pallidum. Optic perineuritis or perioptic neuritis is an inflammation of the optic nerve sheaths that spares the subjacent optic nerves. This gives rise to optic disc swelling without evidence of optic neuropathy (3). Optic perineuritis is seen in conditions that are associated with a leptomeningitis such as viral meningoencephalitis (7) and sarcoidosis (3). Syphilis is also well-known to cause optic peri- ,.,!~jtis, but it more commonly causes a true optic , .,' (.») t,o, llwntioned, all reports of 1Gill Nellro-oplrthalmol, Vol. 7. No.3, 1987 optic perineuritis caused by syphilis have been bilateral (3-5), whereas both of our patients had unilateral involvement. The differential diagnosis of unilateral optic disc edema is extensive and includes demyelination, ischemia, endocrinopathy, inflammation, and compression (1). However, the lack of any demonstrable optic neuropathy distinguishes our cases from these. Unilateral disc swelling may occasionally be seen with increased intracranial pressure in the presence of anomalous and asymmetric venous drainage of the orbit or contralateral optic atrophy (2), but the normal cerebrospinal fluid pressure seen in our cases rules this out. In addition, syphilis may cause unilateral uveitis (9) that can result in optic disc swelling, but the lack of significant vitreous reaction in our cases excludes this possibility. Clinically these cases most resemble the big blind spot syndrome. This and papillophlebitis both present as unilateral optic disc edema without optic nerve dysfunction (2). Papillophlebitis is presumed to be a manifestation of central retinal vein occlusion in patients with enough collateral venous drainage to protect the eye from more serious residue. The big blind spot syndrome is of unknown etiology. It can be distinguished from papillophlebitis by fewer hemorrhages around the posterior pole (2) and less venous congestion. Both of these conditions can be easily distinguished from unilateral syphilitic optic perineuritis by the presence of reactive serology and abnormal spinal fluid (2,6,9). Therefore, it is essential to include syphilis specifically in the differential diagnosis of these syndromes. The diagnosis of syphilitic optic neuritis depends on a high index of suspicion and the appropriate interpretation of serological tests. Nonspecific tests, such as the VORL and RPR, may be falsely negative in many cases of neurosyphilis and so specific testing such as the FTA-ABS must be done (9,10). Any patient with unilateral disc edema and a positive FTA-ABS should undergo lumbar puncture to rule out central nervouS system involvement. A diagnosis of neurosyphilis can be strictly based on the presence of two of the three following criteria within the cerebrospinal fluid: (a) positive VORL, (b) increased protein, or (c) greater than 5 WBC per 10 mm (4). Conversely, a negative serum FTA-ABS virtually excludes the diagnosis of neurosyphiliS (9,10). REFERENCES 1. Miller NR. The big blind spot syndrome: Unilateral optic diSC edema without visual loss or increased intracranial UNILATERAL SYPHILITIC OPTIC PERINEURITIS 169 pressure. In Smith, JL, ed. Neuro-ophthalmology update. New York: Masson, 1977;163-9. 2. Rosenberg ML, O'Connor P, Carter J. Idiopathic unilateral disc edema: The big blind spot syndrome. JClin Neuro-ophthalmo/ 1984;4:181-4. 3. Miller NR. Clinical neuro-ophthalmology, vol. 1. Baltimore: Williams and Wilkins, 1983;240-3. 4. Bush JA, Ryan EJ. Syphilitic optic perineuritis. Am JOphthalmol 1981;91:404-6. 5. Kline LB, Johnson WB. Syphilitic optic perineuritis and uveitis. In Smith, JL ed., Neuro-ophthalmology focus 1980. New York: Masson 1981;77-84. 6. Conn LL, Hoyt WF. Papillophlebitis: a cause of protracted yet benign optic disc edema. Eye, Ear, Nose, Throat 1966;45:62-68. 7. Silverstein A. Papilledema with acute viral infections of the brain. Mt Sinai Med J1977;41:435-43. 8. Weinstein JM, Lexow SS, Ho P, Spickards A. Acute syphilitic optic neuritis. Arch OphthalmoI1981;99:1392-5. 9. Spoor TC, et al. Ocular syphilis-acute and chronic. JClin Neurol-ophthalmoI1983;3:197 -203. 10. Simon RP. Neurosyphilis. Arch Neural 1985;42:606-13. 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