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Rheumatoid arthritis can be accompanied by a range of ocular manifestations
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Rheumatoid arthritis (RA) is a chronic, multisystem inflammatory condition whose etiology is not fully understood. It fits into the connective tissue autoimmune category of illnesses. An individual’s genetic background plays a critical role in both the susceptibility to and severity of RA. It has a worldwide distribution and no racial or ethnic predilection. This disease affects individuals at any age but its incidence does rise significantly with increasing age. Women are affected three times more often than men.
Although RA can begin abruptly, the typical presentation is that of a slow and progressive development of symptoms over a period of weeks or months. Often, constitutional symptoms of fever, malaise, morning stiffness and weight loss herald the onset of the disease.
Articular inflammation (swelling, pain and warmth) of the joints soon follows. The number of involved joints is highly variable, but the process is eventually polyarticular in most people. Almost any joint may be involved, but there is an increased tendency for peripheral joint involvement with sparing of the axial skeleton. The joints involved most often are the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints of the hands, wrists, elbows and ankles; metatarsophalangeal (MTP) joints of the foot; and temporomandibular joints. Involvement of shoulders, hip, sternoclavicular and cricoarytenoid (cartilage and muscle of the larynx) joints is less common.
Classification criteria
Classification criteria for RA were originally drafted in 1956 by the American College of Rheumatology and were revised in 1987. You can access these classification guidelines at www.shim.org/rheumatology/1987ra.html.
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In addition to ocular involvement, the greatest morbidity of this disease results from hand involvement. The swelling that affects the hands varies throughout the day and characteristically assumes a fusiform or sausage configuration. Palpation reveals warmth and frequently fluid within the joint. Marked involvement of the MCP and PIP hand joints results in the characteristic ulnar drift — the fingers, rather than straight extensions of the hand, point toward the ulnar side of the wrist — and swan neck deformities (hyperflexion of the joint), which are often seen with boutonniere deformity (hyperextension of the joint).
Other findings include spindling of the fingers, tendon nodules and subluxation causing the heads of the metacarpals to ride up and over the heads of the phalanges, such that the knuckles appear very prominent.
Clinical evaluation is usually all that is necessary to make the diagnosis of RA. Rheumatoid factor (RF) is the most specific laboratory test to order if one suspects RA, but it is only positive in 70% to 80% of patients with RA. In addition, RF may be detected in the serum of apparently normal individuals, especially people older than 50 and smokers. Other tests such as erythrocyte sedimentation rate, C-reactive protein and antinuclear antibody are less specific for RA.
X-ray evaluation of joint damage in RA may exhibit periarticular osteoporosis, joint space narrowing due to generalized cartilage loss and juxtaarticular erosions, generally at the point of attachment of the joint capsule. Although the axial skeleton is usually not affected, cervical spine involvement may be present and can be quite severe, resulting in subluxation, vertebral endplate erosions, spondylodiscitis and disc space narrowing without osteophytes.
Systemic involvement
Other systemic involvement can also occur. Pulmonary findings include pleurisy with or without effusion and can be seen in up to 70% of patients. Other pulmonary findings include bronchiolitis obliterans, pneumothorax or rheumatoid pneumoconiosis (Caplan’s syndrome). The two major forms of cardiac involvement in RA are myocarditis and pericarditis. Pericarditis can occur in up to 40% of patients with RA.
Anemia is the most common hematologic abnormality. About 1% of patients with RA will develop Felty’s syndrome, which is characterized by the triad of neutropenia, splenomegaly and deforming RA. Inflammation of the blood vessels (vasculitis) is seen in 30% of patients with RA. This vasculitis is believed responsible for a number of accompanying manifestations, including fever, mononeuritis multiplex, Raynaud’s phenomenon, chronic leg ulcers, mucosal erosions of the gastrointestinal tract and necrotizing mesarteritis.
Ocular involvement
The ocular conditions associated with RA predominantly involve the anterior segment and include the following:
- Episcleritis — This may be nodular or diffuse, but the majority of cases are diffuse. Only the episclera is swollen with superficial dilated blood vessels but no underlying scleral involvement. The inflamed areas are tender to touch, but there is no deep pain. Treatment includes cold compresses, topical vasoconstrictors, systemic nonsteroidal anti-inflammatory drugs (NSAIDs) and topical corticosteroids.
- Scleritis — This may be diffuse and is the most benign form of scleritis. Nodular scleritis is characterized by localized inflammation with a tender immobile nodule. Necrotizing scleritis is the most destructive form of scleritis, and the vast majority of patients with this form of the disease (up to 90%) have an associated systemic disorder such as RA. Necrotizing scleritis with inflammation is usually bilateral and presents with white avascular areas surrounded by swollen sclera with vascular engorgement. Eventually, the involved areas develop necrosis from the avascularity, staphyloma and perforation from the scleral thinning. Necrotizing scleritis without inflammation is also called scleromalacia perforans (SP), is usually bilateral and is often seen with RA. It is characterized by thinning of the sclera in a seemingly quiet eye and rarely leads to perforation.
- Posterior scleritis — It may accompany the anterior scleritis but may occur in isolation. Uveal effusions, exudative retinal detachments and disc swelling may accompany the scleral inflammation. All forms of scleritis, whether anterior or posterior (except for SP), are accompanied by pain that is often severe. Systemic therapy is required for scleritis. Treatment is based on progression of ocular disease or persistent inflammation. This therapy may include NSAIDs, corticosteroids (oral or intravenous) or second-line immunosuppressive agents, such as cyclophosphamide, cyclosporine or methotrexate.
- Corneal involvement — Significant corneal manifestations in patients with RA can occur with or without accompanying scleritis and are the leading cause of vision loss. These include keratomalacia, which is a severe progressive melting of the corneal stroma and is seen in association with necrotizing scleritis; sclerosing keratitis, which results in thickened, opacified and vascularized areas of peripheral cornea; acute stromal keratitis seen with diffuse or nodular scleritis; and peripheral corneal furrowing, which is a circumferential thinning of the corneal stroma.
- Keratoconjunctivitis sicca (KCS) — KCS is the most common ocular finding of RA and is present in up to 25% of patients. Symptoms of KCS include dryness, foreign body sensation, burning, grittiness and blurred vision. About 15% of patients with RA develop Sjögren’s syndrome, characterized by impaired secretion of saliva and tears, dry mouth (xerostomia) and dry eyes (KCS). Sjögren’s syndrome is a multisystem disorder whose extraglandular findings include pulmonary and renal involvement, Raynaud’s phenomenon, liver changes and the risk of developing lymphomas.
For Your Information:
- Leonid Skorin Jr., OD, DO, FAAO, FAOCO, can be reached at the Albert Lea Eye Clinic, Mayo Health System, 1206 W. Front St., Albert Lea, MN 56007; (507) 373-8214; fax: (507) 373-2819; skorin.leonid@mayo.edu.