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Show Neuroretinitis With Retrobulbar Involvement Michael S. Vaphiades, DO, Eric H. Wigton, MD, Hossein Ameri, MD, Andrew G. Lee, MD Abstract: Two patients with neuroretinitis are presented, both having MRI abnormalities of the orbital portion of the optic nerve. We review previous reports of CT and MRI findings in patients with neuroretinitis and propose a spectrum of neuroimaging abnormalities in these patients. Journal of Neuro-Ophthalmology 2011;31:12-15 doi: 10.1097/WNO.0b013e3181e7e4c8 2011 by North American Neuro-Ophthalmology Society Neuroretinitis is an inflammatory optic neuropathy characterized by optic disc edema associated with a macular star. Using fluorescein angiography, Gass (1) demonstrated that the macular exudates arise from leakage of proteinaceous material from vessels on the surface of the optic disc. This pathogenic mechanism has been confirmed using optical coherence tomography (OCT) (2). There are few reports of neuroimaging studies in patients with neuroretinitis (3-5). In general, such studies are normal (6). We report 2 patients with neuroretinitis in which MRI demonstrated abnormalities of the orbital optic nerve and propose that patients with neuroretinitis have a spectrum of neuroimaging findings. CASE 1 A 6-year-old girl presented with a 4-day history of painless visual loss in the left eye. Three years previously she suffered a decrease in vision in the right eye due to neuroretinitis. At that time, testing for Bartonella, Lyme, and syphilis was negative and the patient was not treated. In addition, contrast-enhanced MRI of the brain and orbits without fat suppression was found to be normal. Examination showed normal vital signs, a visual acuity of no light perception in the right eye and 20/400 in the left eye. Color vision was diminished in the left eye, and the right pupil was amaurotic. The right optic nerve was pale with pigmentary changes in the macula, while the left fundus showed optic disc edema and a macular star (Fig. 1). Laboratory studies for Bartonella, angiotensin-converting enzyme, Lyme, Toxoplasma, Toxocara, syphilis, and neu-romyelitis optica antibodies were all negative. A contrast-enhanced fat-suppressed orbital MRI revealed diffuse enhancement of the left optic nerve and sheath (Fig. 2). Lumbar puncture showed a normal formula and was neg-ative for oligoclonal bands. The patient was treated with 250 mg oral azithromycin daily for 5 days, and 5 days of high-dose intravenous meth-ylprednisolone( 500mg/day).Eightweeks later, her visionhad improved to 20/20 in the left eye. The patient now correctly identified the Ishihara color plates, and the left fundus showed mild optic disc pallor and a resolving macular star. CASE 2 A 23-year-old man developed sudden onset of a headache and pain with eye movement associated with visual loss in the left eye. His medical and ocular histories were un-remarkable. He was scratched by a 3-month-old kitten 2 weeks previously and developed fever, which resolved spontaneously. Examination showed normal vital signs, visual acuity of 20/20 in the right eye and counting fingers in the left eye. His pupils were isocoric with a left relative afferent pupillary defect. Automated visual field testing was normal in the right eye and demonstrated an inferior arcuate defect in the left eye. Extraocular movements, slit-lamp examination, and the right fundus were normal. The left optic disc was swollen with subretinal fluid and striae in the macula and dot hemorrhages in the peripheral retina (Fig. 3A). Departments of Ophthalmology (MSV, EHW), Neurology (MSV), and Neurosurgery (MSV) University of Alabama at Birmingham, Birmingham, Alabama; Department of Ophthalmology and Visual Sciences (HA, AGL), University of Texas Medical Branch, Galveston, Texas; Department of Ophthalmology (AGL), The Methodist Hospital, Houston, Texas; and Departments of Ophthalmology, Neurology, and Neurosurgery, Weill Cornell Medical College (AGL), New York, New York. Supported in part by an unrestricted grant from the Research to Prevent Blindness, Inc, New York, NY, and The Eyesight Foundation. Address correspondence to Michael S. Vaphiades, DO, Department of Ophthalmology, UAB, 700 South 18th Street, Suite 601, Birmingham, AL 35233; E-mail: vaph@uab.edu 12 Vaphiades et al: J Neuro-Ophthalmol 2011; 31: 12-15 Original Contribution Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Complete blood count, anti-HIV-1 and HIV-2 anti-bodies, syphilis, and Bartonella studies were negative. Given the history of contact with a cat, the patient was treated for presumed cat scratch disease with 500 mg oral azithromycin on day 1, followed by 250 mg daily for 4 days. Because vision failed to improve over the ensuing 1 week, MRI was performed. There was enhancement of the left optic nerve head and contiguous 3-mm orbital portion of the left optic nerve (Fig. 4). An OCT of the left eye con-firmed the presence of subretinal fluid causing macular thickening at 976 mm versus normal right macular thickness of 339 mm. One week later, the patient developed amacular star in the left eye (Fig. 3B), and he was treated with a 10-day course of tetracycline. Serology for Lyme, Toxoplasma, angiotensin-converting enzyme, and a chest radiograph were normal. Repeat serology for Bartonella henselae showed a positive IgG titer (1:128). The patient showed progressive improvement in his vision, and 2 months later, he had an acuity of 20/40 in the left eye, with a less prominent macular star (Fig. 3C). DISCUSSION Our patients had neuroretinitis, one due to Bartonella henselae and the other of unknown cause, and in both patients, neuroimaging demonstrated involvement of the orbital portion of the optic nerve. Although classically the macular star figure is the hallmark of neuroretinitis, the star figure is a late sign following the optic disc edema phase and peripapillary subretinal fluid accumulation by 1-3 weeks (7). The subretinal fluid in the macula can be detected on OCT before the development of the star (2). Neuroimaging abnormalities in patients with neuro-retinitis have been infrequently reported. Zhang et al (3) reported a case of idiopathic neuroretinitis in which CT revealed ‘‘tubular enlargement of the optic nerve and postcontrast enhancement.'' Histopathologic examination was consistent with optic perineuritis. Wals et al (4) re-ported a similar case of neuroretinitis of unknown cause associated with optic perineuritis. The MRI demonstrated enhancement and thickening of the involved optic nerve sheath with sparing of the nerve. Fat suppression of the FIG. 1. Case 1. A. Optic disc pallor with macular pigmentary change in the right eye. B. Optic disc edema with a macular star figure in the left eye. FIG. 2. Case 1. Postcontrast fat-suppressed T1 axial (A) and coronal (B) orbital MRI demonstrates left optic nerve and sheath enhancement (arrows). Original Contribution Vaphiades et al: J Neuro-Ophthalmol 2011; 31: 12-15 13 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. orbital soft tissue further supported the diagnosis of optic perineuritis. Schmalfuss et al (5) evaluated the MRI char-acteristics of patients with optic neuropathy of all types. Nine of their 82 patients were diagnosed with cat scratch disease. In 5 of the 9, optic nerve enhancement was present on contrasted orbital MRI at the optic nerve-globe junction with extension of up to 4 mm within the orbital segment of the nerve. At the time of MRI scanning, only 1 of these 5 patients had the macular findings of neuroretinitis. Neuroimaging findings in our 2 patients add further evidence that orbital optic nerve enhancement may be seen in neuroretinitis. No specific cause was found for neuro-retinitis in our first patient despite extensive evaluation. Clinically, this case fits the category of recurrent neuro-retinitis as reported by Purvin and Chioran (6). Seven such cases were described, all of unknown etiology and, in general, a poor visual outcome. Radiologic studies were reported to be normal, but it was not specified if these scans FIG. 3. Case 2. Evolution of neuroretinitis in the left eye. A. At initial presentation, there is swelling of the optic disc and retina. B. One week later, macular star formation is evident. C. Two months later, mild optic disc pallor is present with a resolving macular star. Original Contribution 14 Vaphiades et al: J Neuro-Ophthalmol 2011; 31: 12-15 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. included fat-suppressed orbital views. Our second patient was found to have cat scratch disease as the cause of neu-roretinitis. Short-segment MRI enhancement localized to the optic nerve-globe junction has been reported as a highly specific sign for cat scratch neuroretinitis (5). Our case is consistent with this observation. The neuroimaging results in our 2 patients support the fact that a macular star does not exclude retrobulbar pathology. Perhaps, in some cases of neuroretinitis, the inflammation is so severe and widespread that it extends posteriorly from the optic disc to include the retrobulbar optic nerve. Blood-brain barrier breakdown, similar to what occurs at the level of the optic disc, may produce retrobulbar optic nerve enhancement on contrast-enhanced fat-sup-pressed T1 orbital MRI. The fundus findings in some cases of neuroretinitis may not reflect the extent of the disease. In summary, there appears to be a spectrum of neuro-imaging findings in neuroretinitis: 1. Normal optic nerve. 2. Intraocular optic disc enhancement at the nerve-globe junction. 3. Optic nerve sheath enhancement (optic perineuritis). 4. Optic nerve and optic sheath enhancement. REFERENCES 1. Gass JD. Diseases of the optic nerve that may simulate macular disease. Trans Sect Ophthalmol Am Acad Ophthalmol Otolaryngol. 1977;83:763-770. 2. Kitamei H, Suzuki Y, TakahashiM, Katsuta S, Kato H, YokoiM, Kase M. Retinal angiography and optical coherence tomography disclose focal optic disc vascular leakage and lipid-rich fluid accumulation within the retina in a patient with Leber idiopathic stellate neuroretinitis. J Neuroophthalmol. 2009:29;203-207. 3. Zhang TL, Shao SF, Zhang T, Meng CL, Fei PF, Zhang W, Sun YM. Idiopathic inflammation of optic nerve simulating optic nerve sheath meningioma: CT demonstration. J Comput Assist Tomogr. 1987;11:360-361. 4. Wals KT, Ansari H, Kiss S, Langton K, Silver AJ, Odel JG. Simultaneous occurrence of neuroretinitis and optic perineuritis in a single eye. J Neuroophthalmol. 2003;23: 24-27. 5. Schmalfuss IM, Dean CW, Sistrom C, Bhatti T. Optic neuropathy secondary to cat scratch disease: distinguishing MR imaging features from other types of optic neuropathies. Am J Neuroradiol. 2005;26:1310-1316. 6. Purvin VA, Chioran G. Recurrent neuroretinitis. Arch Ophthalmol. 1994;112:365-371. 7. Wade NK, Levi L, Jones MR, Bhisitkul R, Fine L, Cunningham ET. Optic disk edema associated with peripapillary serous retinal detachment: an early sign of systemic Bartonella henselae infection. Am J Ophthalmol. 2000;130:327-334. FIG. 4. Postcontrast fat-suppressed T1 axial orbital MRI showing enhancement of the left optic nerve head and contiguous 3 mm of the optic nerve (Case 2). Original Contribution Vaphiades et al: J Neuro-Ophthalmol 2011; 31: 12-15 15 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. |
