February 13, 2020
6 min read
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Young woman presents with unilateral eye discomfort

Macula OCT through a patch of retinal pigment epithelium change showed focal subretinal fluid.

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Alison J. Lauter
Alison J. Lauter
Sarah E. Thornton
Sarah E. Thornton

A 24-year-old African American woman with a medical history of right-sided Bell’s palsy, hidradenitis suppurativa and borderline hypertension was referred to the neuro-ophthalmology clinic at Tufts Medical Center with 3 weeks of right eye discomfort. She initially had a pressure-like discomfort in the right eye that then developed into a dull pain with eye movement. The pain improved somewhat with acetaminophen. She also noticed a blurred spot in the vision of her right eye. Her medications included chlorhexidine skin cleanser, oral contraceptives and artificial tears. She had no known family history of eye or autoimmune disease. She did not smoke cigarettes or drink alcohol. She had no neurologic symptoms and no cough, joint pain or rash.

Examination

Visual acuities were 20/20 in both eyes. Pupils were symmetric and briskly reactive to light with no afferent pupillary defect. IOP was 18 mm Hg in both eyes. Color vision was full in both eyes when tested with HRR plates. Confrontation visual fields were full in both eyes. Extraocular movements were full in both eyes with pain in the right eye.

 Color fundus photos
Figure 1. Color fundus photo of the right eye with mild disc edema and patch of RPE changes along superior arcade (a). Left optic nerve is unremarkable (b).

Source: Christine L. Benador-Shen, MD, Geetha Athappilly, MD, and Thomas R. Hedges III, MD

OCT of the right optic nerve
Figure 2. OCT of the right optic nerve demonstrating disc edema.

Anterior segment exam of both eyes revealed no conjunctival or scleral injection and no anterior chamber cells. On dilated fundus exam, the right eye had moderate optic nerve edema without hemorrhage, and there was a patch of retinal pigment epithelium (RPE) change along the superior arcade (Figure 1). The left eye did not have any anterior or posterior segment pathology. On OCT, the right optic nerve appeared elevated (Figure 2). Average retinal nerve fiber layer (RNFL) thickness of the right eye was 239 µm compared with 101 µm in the left eye (Figure 3). Automated visual field (Humphrey 30-2) showed enlargement of the blind spot in the right eye while the left eye was normal (Figure 4). Macula OCT through the area of RPE change showed focal subretinal fluid (Figure 5). B-scan ultrasound of the right eye did not show scleral or choroidal thickening or nodules, nor distended optic nerve sheath with fluid in Tenon’s capsule (Figure 6). Fluorescein angiogram performed at an outside clinic showed late leakage and hyperfluorescence of the optic nerve and a hyperfluorescent area along the superior arcade.

OCT RNFL
Figure 3. OCT RNFL analysis of the both eyes showing right optic nerve edema.
HVF 30-2 of the right eye
Figure 4. HVF 30-2 of the right eye demonstrating enlarged blind spot. The left eye is normal.
OCT through lesion
Figure 5. OCT through lesion along superior arcade of right eye demonstrating focal subretinal fluid.
B-scan ultrasound
Figure 6. B-scan ultrasound of the right eye shows no T-sign or scleral thickening.

What is your diagnosis?

See answer on next page.

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Right eye discomfort

The differential diagnosis of painful unilateral optic nerve edema and focal subretinal fluid includes posterior scleritis due to inflammatory or infectious disease. Our patient’s history of Bell’s palsy suggested a possible underlying inflammatory disease such as sarcoidosis, but she had no other positive symptoms and no family history of autoimmune disease. She had no known infectious exposures to suggest tuberculosis or syphilis. B-scan did not show an obvious T-sign in support of posterior scleritis. Optic perineuritis in the spectrum of idiopathic orbital inflammatory syndrome can also present as eye pain with movement and optic nerve swelling without optic nerve dysfunction, as in our patient. Optic neuritis was thought to be unlikely due to her normal color vision and lack of an afferent pupillary defect. Asymmetric idiopathic intracranial hypertension was also considered given her overweight BMI but thought unlikely due to pain.

Case continued

MRI of the brain and orbits with and without gadolinium was performed to determine the etiology of her right eye pain and optic nerve swelling. This showed mild thickening and enhancement of the posterior right sclera with adjacent fat stranding as well as perineural enhancement of the right optic nerve sheath (Figure 7). Workup for infectious and inflammatory diseases was negative, including ACE, lysozyme, ANA, ANCA, QuantiFERON-TB Gold and TPPA. She had no leukocytosis.

Given her MRI findings and negative workup, our patient was diagnosed with idiopathic right posterior scleritis and associated perineuritis, with plan for close follow-up.

Axial MRI orbits
Figure 7. Axial MRI orbits with gadolinium, T1 sequence with fat saturation. Enhancement of the posterior right sclera (red arrow) with fat stranding and perineural enhancement of the right optic nerve sheath (white arrow).

Discussion

Posterior scleritis can be considered to be noninfectious or infectious inflammation of the posterior sclera. A retrospective case series of 99 patients with posterior scleritis found a mean age of onset of 49 years with a two-to-one female predominance. The most common cause is idiopathic within the spectrum of idiopathic orbital inflammation disease. Two other retrospective case reviews found about 60% to 65% of patients had no identifiable etiology. The second most common cause of posterior scleritis is associated autoimmune disease. Rheumatoid arthritis is the most common, although cases of posterior scleritis have also been seen in granulomatosis with polyangiitis, relapsing polychondritis, polyarteritis nodosa, sarcoidosis, lupus, Crohn’s disease and ankylosing spondylitis. Infectious causes of posterior scleritis include herpes zoster, syphilis and tuberculosis. Posterior scleritis may also follow surgery or trauma.

Patients present with normal or severely decreased vision, depending on associated examination findings. Eye pain is often present, although in one study only 60% of patients had pain. About one-third of patients can have concurrent anterior scleritis, and one author suggested that pain may be associated with the severity of anterior involvement. Other potential examination findings include proptosis, shallowing of the anterior chamber, elevated IOP, exudative retinal detachment, subretinal fluid or focal granulomas, choroidal effusion or retinal vasculitis. Our patient had an area of subretinal fluid affecting the posterior pole of the fundus. One retrospective case series found that 18% of patients also had optic disc edema. This may be due to extension of scleral inflammation to the optic nerve sheath causing optic perineuritis, as in our patient.

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The diagnosis of posterior scleritis is often made from B-scan ultrasonography showing thickened scleral and fluid in the Tenon’s capsule (T-sign). Scleral nodules may be present with high internal reflectivity. Fluorescein angiogram may show early pinpoint spots of leakage with late hyperfluorescence and staining in the presence of subretinal fluid. In our patient, B-scan did not show evidence of scleritis, and fluorescein angiogram was not confirmatory of posterior scleritis. In such cases, MRI of the orbits with gadolinium and fat saturation may be helpful in the diagnosis. A retrospective case review of 11 patients with posterior scleritis showed scleral enhancement in all patients. Other signs included scleral thickening or focal periscleral cellulitis. Our patient had scleral enhancement as well as adjacent cellulitis. CT of the orbits with contrast may show a “ring sign” of scleral enhancement. Laboratory workup is necessary to evaluate for collagen vascular disease, vasculitides and possible infection.

Treatment for posterior scleritis includes oral NSAIDs or oral corticosteroids. Many patients respond well to oral treatment. However, if there is recurrence of disease, intravenous steroids or systemic immunomodulatory agents may be used. Patients with posterior scleritis secondary to a systemic disease are more likely to require immunosuppressants. Scleral thinning can be treated surgically with grafts.

Clinical course continued

Our patient was prescribed prednisone as a 2-week taper starting at 80 mg daily. By the second week, her eye pain had resolved. At 1-month follow-up, her vision was stable. OCT of the right eye showed marked improvement of optic disc swelling. Average RNFL decreased from 239 µm to 127 µm in the right eye. She also had resolution of the enlarged blind spot in the right eye on HVF 30-2. She has not had recurrence of her symptoms to date.