Scleritis: Differential Diagnoses & Workup

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Scleritis: Differential Diagnoses & Workup

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Maite Sainz de la Maza, MD, PhD, Associate Professor, Division of Ocular Immunology and Uveitis, Department of Ophthalmology, Hospital Clinico y Provincial, Barcelona, Spain
Contributor Information and Disclosures

Updated: Nov 8, 2007


Workup
Laboratory Studies
Based on the past history, review of systems, and physical examination, select appropriate diagnostic tests to confirm or reject the following suspected associated diseases:
Rheumatoid factor - Rheumatoid arthritis
Antinuclear antibodies - Systemic lupus erythematosus, rheumatoid arthritis, polymyositis, progressive systemic sclerosis, or mixed connective tissue
Antineutrophil cytoplasmic antibodies (ANCA) - Wegener granulomatosis, polyarteritis nodosa, or microscopic polyangiitis
Human leukocyte antigen (HLA) typing - Ankylosing spondylitis, reactive arthritis, psoriatic arthritis, or arthritis associated with inflammatory bowel disease
Eosinophil count/immunoglobulin E (IgE) - Allergic angiitis of Churg-Strauss syndrome or atopy
Uric acid - Gout
Erythrocyte sedimentation rate (ESR) - Giant cell arteritis
Hepatitis B surface antigen (HBsAg) - Polyarteritis nodosa
Serologies - Infectious diseases, including syphilis
Tuberculosis (TB) and anergy skin testing - Rare occurrence of TB or sarcoidosis
Imaging Studies
Chest x-ray - TB, Wegener granulomatosis, allergic angiitis of Churg-Strauss syndrome, or atopy
Sinus films - Wegener granulomatosis
Sacroiliac x-ray - Ankylosing spondylitis, reactive arthritis, psoriatic arthritis, or arthritis associated with inflammatory bowel disease
Limb joint x-ray - Rheumatoid arthritis, psoriatic arthritis, arthritis associated with inflammatory bowel disease, or gout
Ultrasonography (A- and B-scan) - Posterior scleritis; most helpful test to aid in diagnosing posterior scleritis, which is characterized by flattening of the posterior aspect of the globe, thickening of the posterior coats of the eye (choroid and sclera), and retrobulbar edema
CT scan - Posterior scleritis; a useful diagnostic tool to aid in detecting the following, which are important to differentiate posterior scleritis from orbital inflammatory diseases and orbital neoplasm: extraocular muscle or lacrimal gland enlargement, sinus tissue involvement, and posterior scleral thickening
MRI - Posterior scleritis
MRI is used to differentiate localized inflammatory pseudotumor from posterior scleritis in proptosis or choroidal tumors from posterior scleritis in subretinal mass.
Some orbital tumors, which cause choroidal folds and retinal striae, are also signs of posterior scleritis that are detected successfully by MRI.
Other Tests
Skin testing
Intracutaneous tuberculin purified protein derivative (PPD) - TB
Prick test - Atopy
Smears, cultures, and polymerase chain reaction (PCR) from conjunctival, corneal, episcleral, or scleral scraping - Infectious scleritis
Scleral or corneoscleral biopsy is recommended if smears and culture results are negative at 48 hours, infectious scleritis is still the primary clinical suspicion, and the patient is worsening.
One third of tissue from a biopsy is sent to the microbiology department, where it is homogenized for smears, cultures, and PCR.
The middle third of tissue is transported to the pathology department for histopathology with special stains (eg, periodic acid-Schiff [PAS], Gomori methenamine-silver, acid-fast, calcofluor white).
The last third of tissue is sent to the immunology department for immunofluorescence studies with monoclonal antibodies (eg, anti–herpes simplex virus type 1, anti–varicella-zoster virus antibodies).
PCR of body fluids - Infectious scleritis
Procedures
Low-dose anterior segment fluorescein angiography (FA) combined with anterior segment indocyanine green (ICG) angiography is recommended. ICG distinguishes totally occluded vessels from the temporary obstruction caused by high endothelial venules or vascular spasm seen as nonperfusion with FA. FA identifies new corneal vessels and leakage, whereas ICG does not. ICG locates the site of maximum inflammation and is more valuable in assessing the effects of treatment and when to withdraw that treatment.
Diffuse scleritis
FA - Rapid filling, short transit time, extensive leakage, normal vascular pattern, and deep sclera leakage in early disease
ICG - Rapid filling, short transit time, no leakage except for local vascular damage, and occasionally late deep leakage
Nodular scleritis
FA - Rapid transit time, abnormal leakage pattern, and staining nodules
ICG - Rapid filling, short transit time, and stained nodules
Necrotizing scleritis
FA - Hypoperfusion and venular occlusion, increased transit time, new vessel formation, and deep staining
ICG - Hypoperfusion and venular occlusion, increased transit time, and late leakage from new or damaged vessels
Scleromalacia perforans
FA - Virtually no perfusion
ICG - Leakage in area of necrotic tissue
Posterior scleritis
FA - Retinal pigment epithelial detachments, serous retinal detachment, cystoid edema, choroidal folds, and hyperfluorescent and hypofluorescent areas
ICG - Diffuse zonal choroidal hyperfluorescence intermediate or late phase, pinpoint leakage, delayed choroidal perfusion, and hyperfluorescence in areas of maximal activity
Histologic Findings
Diffuse scleritis or nodular scleritis

A nongranulomatous inflammatory reaction occurs that is characterized by infiltration of mononuclear cells, such as macrophages, lymphocytes, and plasma cells. In the most severe cases, mononuclear cells may organize into granulomatous lesions. Mast cells, neutrophils, and eosinophils may also be present.

Necrotizing scleritis

A granulomatous inflammatory reaction occurs that is characterized by a central area of fibrinoid necrosis, surrounded by epithelioid cells, multinucleated giant cells, lymphocytes, and plasma cells. Neutrophils, mast cells, and eosinophils are dispersed throughout the inflamed tissue and around vessels. Inflammatory microangiopathy, which is characterized by neutrophilic infiltration in and around the episclera and sclera that perforates the vessel walls with or without fibrinoid necrosis, is frequently seen.

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