Psoriatic arthritis
Psoriatic arthritis: Excerpt from Professional Guide to Diseases (Eighth Edition)
Psoriatic arthritis is a rheumatoid-like joint disease associated with psoriasis of nearby skin and nails. Although the arthritis component of this syndrome may be clinically indistinguishable from rheumatoid arthritis, the rheumatoid nodules are absent, and serologic tests for rheumatoid factor are negative. Psoriatic arthritis is usually mild, with intermittent flare-ups, but in rare cases may progress to crippling arthritis mutilans. This disease affects males and females equally; onset usually occurs between ages 30 and 35.
Causes
Evidence suggests that predisposition to psoriatic arthritis is hereditary; 20% to 50% of patients are human leukocyte antigen-B27 positive. However, onset is usually precipitated by streptococcal infection or trauma.
About 5% to 7% of patients with psoriasis develop psoriatic arthritis. It occurs in up to 1% of the general population.
Signs and symptoms
Psoriatic lesions usually precede the arthritic component; however, after the full syndrome is established, joint and skin lesions recur simultaneously. Arthritis may involve one joint or several joints symmetrically. Spinal involvement occurs in some patients. Peripheral joint involvement is most common in the distal interphalangeal joints of the hands, which have a characteristic sausage-like appearance. Nail changes include pitting, transverse ridges, onycholysis, keratosis, yellowing, and destruction. The patient may experience general malaise, fever, and eye involvement.
Diagnosis
Inflammatory arthritis in a patient with psoriatic skin lesions suggests psoriatic arthritis.
CONFIRMING DIAGNOSIS X-rays confirm joint involvement and show:
❑ erosion of terminal phalangeal tufts
❑ “whittling” of the distal end of the terminal phalanges
❑ “pencil-in-cup” deformity of the distal interphalangeal joints
❑ relative absence of osteoporosis
❑ sacroiliitis
❑ atypical spondylitis with syndesmophyte formation. Hyperostosis and paravertebral ossification result, which may lead to vertebral fusion.
Blood studies indicate negative rheumatoid factor and elevated erythrocyte sedimentation rate and uric acid levels.
Treatment
In mild psoriatic arthritis, treatment is supportive and consists of immobilization through bed rest or splints, isometric exercises, paraffin baths, heat therapy, and aspirin and other nonsteroidal anti-inflammatory drugs. Some patients respond well to low-dose systemic corticosteroids; topical steroids may help control skin lesions. Gold salts and, most commonly, methotrexate therapy are effective in treating both the articular and cutaneous effects of psoriatic arthritis. Antimalarials are contraindicated because they can provoke exfoliative dermatitis.
Special considerations
❑ Explain the disease and its treatment to the patient and his family.
❑ Encourage exercise, particularly swimming, to maintain strength and range of motion.
❑ Teach the patient how to apply skin care products and medications correctly; explain possible adverse effects.
❑ Stress the importance of adequate rest and protection of affected joints.
❑ Encourage regular, moderate exposure to the sun.
❑ Refer the patient to the Arthritis Foundation for self-help and support groups.
Book Source Details
- Book Title: Professional Guide to Diseases (Eighth Edition)
- Author(s): Springhouse
- Year of Publication: 2005
- Copyright Details: Professional Guide to Diseases (Eighth Edition), Copyright © 2005 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
» Next page: Septic arthritis (Professional Guide to Diseases (Eighth Edition))
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