|Year : 1998 | Volume
| Issue : 4 | Page : 195-202
Posterior scleritis: Clinical profile and imaging characteristics
Jyotirmay Biswas, Sangeet Mittal, Sudha K Ganesh, Nitin S Shetty, Lingam Gopal.
Medical Research Foundation, Chennai, India
Medical Research Foundation, 18 College Road, Chennai - 600 006
Source of Support: None, Conflict of Interest: None
Posterior scleritis is relatively uncommon and is often misdiagnosed due to its protean manifestations. We report eight cases of posterior scleritis to analyse the clinical profile, ultrasonographic and computed tomography (CT) scan features of this rare disorder. Fundus findings included serous retinal detachment, choroidal folds, retinal folds, subretinal mass, choroidal detachment, disc edema, and macular edema. There was associated anterior scleritis and anterior uveitis in the majority of the cases. In all cases ultrasound with or without CT scan confirmed the clinical diagnosis. All patients responded to systemic steroids except one who required immunosuppressive therapy. This paper describes the clinical profile of a series of posterior scleritis cases highlighting varied clinical presentation, and the role of ultrasound and CT scan findings in the diagnosis.
Keywords: Posterior scleritis, ultrasonography, computed tomography scan, corticosteroid, immunosuppressive agents
|How to cite this article:|
Biswas J, Mittal S, Ganesh SK, Shetty NS, Gopal. L. Posterior scleritis: Clinical profile and imaging characteristics. Indian J Ophthalmol 1998;46:195-202
|RD IS RETINAL DETACHMENT. CF IS COUNTING FIGURES. EOM IS EXTRAOCULAR MOVEMENTS.|
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Posterior scleritis is one of the most commonly misdiagnosed conditions in ophthalmology. Such misdiagnosis occurs due to its variable presentations, and also the relative non-familiarity of the general ophthalmologists with this condition. In addition, several inflammatory and non-inflammatory ocular diseases such as posterior uveitis, Vogt-Koyanagi-Harada syndrome, pseudotumour of the orbit, and central serous chorioretinopathy can closely mimic this condition. Early diagnosis is important because prompt treatment often leads to complete resolution with excellent visual recovery. Ultrasonography has been found to be very useful in the diagnosis of posterior scleritis. Computed Tomography (CT) scan and fundus fluorescein angiography (FFA) [1, 10, 11] can also be used as ancillary tests. We report a series of 8 cases of posterior scleritis which were initially misdiagnosed clinically. Subsequently, clinical examination accompanied by ancillary tests established the diagnosis. To the best of our knowlege, this is the largest series of this uncommon entity from India. The paper describes varied clinical presentation, reason for misdiagnosis, diagnostic clues in each case and guidelines for diagnosis.
|RD IS RETINAL DETACHMENT. CF IS COUNTING FIGURES. EOM IS EXTRAOCULAR MOVEMENTS.|
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| Materials and Methods|| |
We examined the records of all patients who were diagnosed as having posterior scleritis from 1992 to 1996. Out of the 94 cases of scleritis, 8 patients were found to have posterior scleritis. The hospital outpatient records were reviewed in these 8 patients to determine the age, sex, history of systemic ailment and the preliminary diagnosis of the referring ophthalmologist. The information regarding the presenting complaints of the patient, the best corrected visual acuity at time of presentation, external examination including presence or absence of proptosis, range of extraocular movements, slitlamp findings, intraocular pressure, fundus findings including status of optic nerve head, presence or absence of mass, secondary retinal detachment, choroidal folds, ciliochoroidal detachment, etc., were noted. Details of imaging techniques such as ultrasonography (A-scan and B-scan), CT scan, and FFA were evaluated. Ultrasonography (A & B scan) was done in all cases. FFA and CT scan were done subsequent to ultrasonography in 5 cases and were considered unnecessary in 3 cases. Laboratory investigations, including routine haemogram, erythrocyte sedimentation rate, serum rheumatoid factor and serum antinuclear antibodies. Response to treatment and follow-up findings were recorded. The data were analysed. Summary of the cases is given in [Table - 1].
| Results|| |
Between 1992 to 1996, 94 cases of scleritis were seen in our hospital, which is a referral eye centre. Of these only 8 patients (8.5%) were diagnosed as having posterior scleritis. In none of these cases was the referral diagnosis posterior scleritis. The diagnosis by the referring ophthalmologists included conditions like subretinal cyst, retinal detachment, uveal effusion syndrome, panuveitis, retroorbital tumour, neuroretinitis, and choroidal melanoma. The age in these patients ranged from 11 to 46 years (mean 27.8 years, median 35.5 years). There were 4 each of males and females. The presenting complaint among these patients was variable decrease of vision associated with moderate to severe ocular pain. Profound vision loss (<6/60) was seen in 4 cases, while moderate visual loss (<6/24) and mild visual loss (<6/9) occurred in 2 eyes each. 6 out of 8 eyes had associated anterior uveitis which was non-granulomatous in nature. 3 patients had mild ptosis and one patient each had restriction of extraocular movements and proptosis. Fundus changes included secondary retinal detachment (5 eyes), subretinal mass [Figure - 1] (4 eyes), retinal striae (2 eyes), choroidal striae (2 eyes), choroidal detachment (2 eyes), macular edema (2 eyes) and disc edema (2 eyes). All cases were unilateral. However one patient gave a similar history in the other eye and had a few retinal striae with pigmentation indicating a probable resovled posterior scleritis (Case 7). The clinical profile of the 8 cases is summarised in [Table - 1].
Ultrasonography was done in all eyes [Table - 2]. This showed variable degree of thickening of the posterior eye wall (choroid and sclera), associated with edema in the retrobulbar space. 'T' sign due to edema in the tenons space was seen in 3 eyes [Figure - 2]. A shallow serous retinal detachment was seen in 2 eyes. Subretinal mass lesion was seen in 2 eyes and optic nerve head swelling was seen in one eye. Repeat ultrasonography following clinical improvement showed total or almost total reduction in choroidal and scleral thickening [Figure - 3].
FFA was done in 5 cases. 2 cases had evidence of late hyperfluorescence due to staining of inflamed area. 2 eyes showed blocked fluorescence corresponding to the subretinal mass lesion. One eye showed alternate dark and bright bands corresponding to choroidal folds[Figures:4 & 5].
CT scan was done in 5 cases [Table - 2]. Thickening of posterior eye wall was seen in 4 out of 5 eyes [Figure - 6] whereas the scleral thickening could not be made out in one eye. CT scan was not done in 3 eyes as it was not required for diagnosis.
None of the cases had clinical evidence of systemic disease at the time of presentation except one patient who had nonspecific arthiritis.
Laboratory studies revealed positive antinuclear antibodies in one patient (case 2) and raised erythrocytic sedimentation rate in two cases. All except one case showed complete clinical resolution with the use of systemic and topical steroids. In the one case that did not respond to systemic steroid, cyclophosphamide 100 mg per day was given which resulted in resolution of the disease. Although the subretinal mass subsided, few chorioretinal striae still persisted in one case 6 weeks after therapy [Figure - 7]. One case (case 5) developed mild cushingoid features following oral steroid therapy. Follow up ranged from 1 to 46 months (median 12 months). Marked visual improvement was seen in 7 eyes [Table - 1]. The final vision was 6/12 or better in 5 eyes. Vision did not improve in one eye, although the retinal edema subsided clinically. This patient had corneal changes due to an episode of proven viral keratitis (case 1). Recurrence of disease was seen in one eye (case 5) which responded to systemic steroid.
| Discussion|| |
In our series the mean age of presentation was 30 years with the range of 11 to 46 years. The average age in the 3 largest series of posterior scleritis was 47-49 years. The age range in previous reported series was 12-77 years. In our series the youngest patient was 11 years old. Occurrence of posterior scleritis at a young age, though uncommon, has been reported in literature. Woon and coworkers reported 5 cases of posterior scleritis in children. The mean age in their series was 11.6 years (range 9-14 years). In all the reported series there was female preponderance. However, in our series equal sex distribution was observed. However, the rarity of this disorder and small number of cases can account for such disparity.
The most common presentation was seen to be acute loss of vision associated with moderate to severe degree of pain and redness. Associated anterior scleritis or anterior uveitis was seen in 6 out of 8 eyes. In earlier reports also the presence of anterior scleral involvement to variable extent has been seen commonly associated with posterior scleritis. Proptosis, eyelid edema, and restriction of ocular movements can be seen with intense periscleral inflammation spreading to orbit and extraocular muscles.
Protean manifestations of posterior scleritis often make the diagnosis difficult. In our series such varied manifestations were noted. Pain is an important indication of posterior scleritis. Such pain is often located at the brow, temple or zygoma. A careful history should be taken of associated pain in case of any secondary retinal detachment or subretinal mass involving the posterior pole of the fundus, and this should arouse the suspicion of posterior scleritis.
The most striking finding in our series is the inability to diagnose posterior scleritis by the referral ophthalmologist. Such a finding is in accord with the report of Benson and associates who described cases of posterior scleritis where misdiagnosis included intraocular neoplasms, retrobulbar tumour, choroiditis, and central serous choroidopathy. Similarly, in a series of 9 patients described by Singh and co-workers, referral diagnosis included macular edema, retinal detachment, papilloedema, posterior choroidal folds, papillitis, episcleritis, and uveitis. In our series the wide-ranging misdiagnoses made included retinal detachment, uveal effusion syndrome, inflamed pterygium, retrobulbar tumour, panuveitis, central serous choroidopathy, malignant melanoma of the choroid [Table - 1]. This was probably due to the general ophthalmologists' unfamiliarity with this condition and lack of ultrasonographic facility. In a 6-year period, out of 150, 149 new cases in our referral centre only 8 cases (0.005%) of posterior scleritis were diagnosed. In case 1, a cystic lesion was located in the macula leading to a diagnosis of subretinal cyst. An exudative retinal detachment in posterior scleritis can restrict the detachment to the posterior pole. In a series reported by Benson and co-workers, two cases of fundus mass with considerable secondary serous detachment were observed. Our case was similar to case 1 reported by Benson and co-workers where, just anterior to the fovea, an 8 x 8 mm fundus mass was seen. A serous retinal detachment was seen over the mass. In our case, the colour of the mass which was similar to the adjacent fundus and a few retinal striae helped the diagnosis. In addition, there was evidence of anterior scleritis and mild anterior uveitis which increased the suspicion. Finally ultrasound and CT scan confirmed the diagnosis. Our second case had been diagnosed as secondary retinal detachment [Figure - 2]. In this case, though there was no anterior segment inflammation, localised retinal detachment with associated retinal striae led to clinical suspicion. Such retinal striae can be the only indication in patients with relatively mild diffuse inflammation of posterior sclera. However, such retinal striae may be associated with orbital tumours, optic nerve disorders, thyroid eye diseases, gross hypotony, following trauma, orbital cellulitis or even idiopathic and is not an absolute indication of posterior scleritis.
In our third case uveal effusion syndrome was considered as the patient had bullous retinal detachment. Uveal effusion syndrome is an insidious painless progression usually causing bilateral non-rhegmatogenous bullous retinal detachment. There is no associated anterior uveitis, or anterior scleritis. Such patients respond poorly to corticosteroid.
In our fourth case, a prominent anterior segment inflammation, led to a clinical diagnosis of panuveitis. Some anterior scleral involvement is often associated with posterior scleritis. In the acute stage mild non-granulomatous anterior uveitis can also be seen. Wilhelmus and associates reported anterior uveitis in 50% of their cases of both anterior and posterior scleritis. They were associated with few or no keratic precipitates. Vitreous cells are minimal, in contrast to panuveitis. Some anterior scleral involvement is often associated with posterior scleritis. They were with few or no keratic precipitates. Vitreous cells are minimal, in contrast to panuveitis where dense vitreous inflammation is seen. Anterior scleritis can often be associated with posterior scleritis. In a series of 11 cases described by Foster and co-workers the initial site of scleritis was anterior in 3 cases and 4 cases had anterior scleritis associated with it at the initial presentation.
In case 5 severe pain, conjunctival chemosis, proptosis and restriction of ocular movements indicated a diagnosis of pseudotumour. However, associated anterior scleritis and anterior uveitis and history of arthritis indicated a suspicion of posterior scleritis. Subsequently, ultrasonography indicated posterior scleritis. Pseudotumour can closely mimic an acute posterior scleritis, particularly when associated with anterior scleritis. Both conditions can cause retino-choroidal striae. The diagnosis depends on mostly demonstration of an orbital mass by ultrasonography or CT scan. In both conditions ultrasonography and CT scan show scleral thickening, retrobulbar edema, extraocular muscle enlargement and diffuse orbital involvement. However, in posterior scleritis intraocular findings like anterior uveitis, retinal and optic nerve involvement are more prominent than extraocular findings. Associated arthritis is seen in posterior scleritis., For instance, a series reported by Foster and associates, 3 had associated arthritis. Pseudotumour is not known to be associated with collagen disease.
In case 6 prominent anterior scleritis finding indicated inflammed pterygium however characteristic posterior segment finding indicated the diagnosis of posterior scleritis. Optic disc edema was also noted in case 6. Such disc edema can also accompany posterior scleritis and can be the predominant feature if inflammation involves sclera and choroid adjacent to the optic nerve head. In a series reported by Singh and co-workers, 6 out of their 9 cases had optic disc involvement. 5 had papilloedema, and one had papillitis as the referral diagnosis.
A central serous choroidopathy (CSC) can closely mimic posterior scleritis. Distinguishing features are that it does not cause anterior scleritis, or anterior uveitis and usually has clear subretinal fluid. Fluorescein angiography and ultrasonography can certainly differentiate from posterior scleritis. FFA will show commonly single or rarely multiple leaks. Ultrasonography will show retinal elevation and not the scleral and choroidal thickening and retrobulbar edema. In one case (case 7) the diagnosis of central serous chorioretinopathy was made based on the serous retinal detachment involving the macular area.
In case 7 diagnosis of choroidal haemanngioma was also considered. Choroidal haemangioma also can mimic posterior scleritis, closely. The fundus usually shows an orange red mass (tomato ketchup fundus). FFA and ultrasonography can often unequivocally establish choroidal haemangioma. FFA though do not show any characteristic sign in posterior scleritis but in choroidal haemangioma will show early hyperfluorescence of large calibre choroidal blood vessels either prior to or simultaneously with the initial filling of retinal arteries and the entire lesion becomes extremely hyper-fluorescent. Ultrasonography also did not indicate typical appearance of haemangioma.
In case 8 a diagnosis of malignant melanoma of the choroid was made based on the prominent mass seen in the fundus. Though the mass was not pigmented as is seen in majority of melanoma cases, an amelanotic melanoma could not be ruled out. Although a melanoma involves the same age group, can have a non-pigmented mass lesion (amelanotic) and secondary retinal detachment. However, they rarely cause pain (unless necrotic). Fundus lesions are not of the same colour as the adjacent normal retinal pigment epithelium. Lipofuscin pigments are also frequently present on its surface. Moreover choroidal folds are quite uncommon. Ultrasonographic features are often characteristic with choroidal mass with low internal reflectivity and choroidal excavation. In contrast, ultrasound of posterior scleritis shows focal thickening of sclera and choroid, high internal reflectivity and retrobulbar edema. There are several reports of such mistaken clinical diagnosis reported in the literature and several eyes have been even enucleated for the same.,, As no diagnostic sign exists in posterior scleritis, ancillary tests are found to be very useful for diagnosis. In all our cases it was the B-scan ultrasonographic findings which provided the most strong evidence for diagnosis. Ultrasound should be done in case of choroidal folds where diagnosis is not certain.,  The characteristic findings included flattening and thickening of posterior coats of the eye and retrobulbar edema. If retrobulbar edema surround the optic nerve, 'T' sign occurs. It is exhibited by squaring of the normally rounded optic nerve shadow along with edema extending along with adjacent sclera. One should remember such a 'T' sign is not evident in mild posterior scleritis. In our series, in only two cases was 'T' sign present. For confirmation one can attenuate the intensity of the sound beam to assess the persistence of the mass lesion due to high internal reflectivity of the sclera. Such technique can differentiate posterior scleritis from posterior uveitis where only choroidal thickening and no scleral thickening occurs.
Computerized tomography has also been found to be beneficial in the diagnosis of posterior scleritis. It shows scleral thickening which can be enhanced by contrast injections. However ultrasound was found to be superior due to its high resolution. In our study in one case although ultrasound showed scleral thickening, CT scan failed to reveal such thickening; this is due to the high resolution capacity of ultrasound. One should remember that orbital pseudotumour can also cause similar ultrasonographic and CT scan findings. However, anterior uveitis, optic disc edema, subretinal mass and choroidal folds will indicate a diagnosis of posterior scleritis. Magnetic resonace imaging (MRI) also can be used in the diagnosis of posterior scleritis but is not required in majority of cases. We found that ultrasonography often can establish the diagnosis and, in majority of cases CT scan and MRI is not needed.
While FFA does not provide characteristic findings, is often found to be very useful to distinguish between central serous retinopathy and choroidal haemangioma. FFA showed in our series blocked fluorescence in initial arteriovenous phase and diffuse hyperfluorescence in late phase with no leak. Associated retinal pigment epithelial detachment, serous retinal detachment, disc edema and cystoid macular edema can be distinguished by FFA. Choroidal folds are seen as alternating hyperfluorescent and hypofluorescent bands. Retinal striae are not seen on fluorescein angiography and thus one can distinguish it from the choroidal striae.
Management of posterior scleritis is less challenging in contrast to the diagnosis. Non-steroidal agents, oral steroids, and periocular steroids have been used successfully in the management of posterior scleritis. Complete resolution of inflammation often takes several weeks. Our series indicate corticosteroid should be the first line of therapy in this entity as all patients except one responded to a course of oral steroid Cyclophosphamide at the dose of 2.5 mg/kg of body weight. Singh and co-workers reported unaffected course and outcome following topical and systemic steroid in 3 out of 9 cases in their series. Bertelson found in addition to oral steroid periocular steroids are generally effective in this condition. Rosenbaum and Robertson reported 6 cases of posterior scleritis that responded to oral indomethacin 150 mg per day in 3 divided doses. There are reports of usage of pulse therapy with intravenous methylprednisolone or cyclophosphamide. Wakefield and Mc Cluskey have used oral cyclosporine in severe form of this disease. Such therapy can be considered in cases which are refractory to corticosteroid treatment. Choroidal folds are known to persist even after resolution of scleritis as seen in our case 7 [Figure - 6].
Early diagnosis of posterior scleritis gains importance due to its excellent response to anti-inflammatory medication, particularly systemic steroid. High index of suspicion should be kept in any subretinal mass lesion or secondary retinal detachment involving the posterior pole if associated with pain. In such a case a B-scan ultrasonogram can be done to establish the diagnosis. Further ancillary studies like FFA and CT scan can be done in case of diagnostic dilemma.
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[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6], [Figure - 7]
[Table - 1], [Table - 2]