Page 513 - First Aid for the USMLE Step 1 2020, Thirtieth edition [MedicalBooksVN.com]_Neat

Musculoskeletal, skin, and connective tissue ` pathology Musculoskeletal, skin, and connective tissue ` pathology section iii 469

Seronegative Arthritis without rheumatoid factor (no anti-IgG antibody). Strong association with HLA-B27
spondyloarthritis (MHC class I serotype). Subtypes (PAIR) share variable occurrence of inflammatory back
pain (associated with morning stiffness, improves with exercise), peripheral arthritis, enthesitis
(inflamed insertion sites of tendons, eg, Achilles), dactylitis (“sausage fingers”), uveitis.
Psoriatic arthritis Associated with skin psoriasis and nail lesions. Seen in fewer than ⁄3 of patients with psoriasis.
1
Asymmetric and patchy involvement A .
Dactylitis and “pencil-in-cup” deformity of
DIP on x-ray B .
Ankylosing Symmetric involvement of spine and sacroiliac Bamboo spine (vertebral fusion) C .
spondylitis joints Ž ankylosis (joint fusion), uveitis, aortic Costovertebral and costosternal ankylosis may
regurgitation. cause restrictive lung disease. Monitor degree of
reduced chest wall expansion to assess disease
severity.
More common in males.
Inflammatory bowel Crohn disease and ulcerative colitis are often
disease associated with spondyloarthritis.

Reactive arthritis Formerly called Reiter syndrome. “Can’t see, can’t pee, can’t bend my knee.”
Classic triad: Shigella, Yersinia, Chlamydia, Campylobacter,
ƒ Conjunctivitis Salmonella (ShY ChiCS).
ƒ Urethritis
ƒ Arthritis
A B C

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