What is the recommended physical exam and treatment approach for patients with seronegative arthropathies?

Physical Examination for Seronegative Arthropathies

The physical examination for seronegative arthropathies must systematically assess axial joints (sacroiliac and spine), peripheral joints, entheses, and extra-articular manifestations, with particular attention to asymmetric joint involvement, dactylitis, and enthesitis that distinguish these conditions from rheumatoid arthritis. 1

Systematic Joint Assessment

Axial Skeleton Examination

• Sacroiliac joints: Palpate for tenderness and perform provocative maneuvers (FABER test, Gaenslen's test, sacral compression) to elicit pain suggestive of sacroiliitis, which is a hallmark early feature of axial spondyloarthritis 1, 2
• Spinal mobility: Measure the modified Schober's test (normal >5 cm expansion), chest expansion (normal >2.5 cm), and occiput-to-wall distance to quantify spinal restriction 1
• Cervical spine: Assess rotation, lateral flexion, and forward flexion, as cervical involvement occurs in advanced disease 1

Peripheral Joint Examination

• Distribution pattern: Document asymmetric oligoarthritis (≤4 joints), which is more characteristic of seronegative spondyloarthropathies than the symmetric polyarthritis of rheumatoid arthritis 1, 3
• Distal interphalangeal (DIP) joints: Specifically examine DIP joints, as their involvement strongly suggests psoriatic arthritis rather than rheumatoid arthritis (which rarely affects DIPs) 4, 3
• Large joints: Assess knees, ankles, hips, shoulders, and elbows for swelling, warmth, effusion, and range of motion limitation 1, 4
• Small joints of hands and feet: Examine metacarpophalangeal, proximal interphalangeal, and metatarsophalangeal joints for synovitis 4

Enthesitis Assessment

• Achilles tendon insertion: Palpate the calcaneal insertion bilaterally for tenderness and swelling, as enthesitis is a distinguishing feature of spondyloarthropathies 1, 2
• Plantar fascia insertion: Examine the heel for plantar fasciitis, which is common in reactive arthritis and other seronegative conditions 2
• Other entheses: Check lateral epicondyles, greater trochanters, iliac crests, and costochondral junctions for tenderness 1

Dactylitis ("Sausage Digit")

• Fingers and toes: Inspect for diffuse swelling of entire digits, which indicates inflammation of flexor tendons, joints, and soft tissues—highly specific for psoriatic and reactive arthritis 4, 2

Extra-Articular Manifestations

Dermatologic Examination

• Psoriatic plaques: Thoroughly examine scalp, extensor surfaces (elbows, knees), umbilicus, intergluteal cleft, and nails for psoriasis, as skin involvement may be subtle or precede arthritis 4
• Nail changes: Look for pitting, onycholysis, oil spots, and subungual hyperkeratosis characteristic of psoriatic arthritis 4
• Keratoderma blennorrhagicum: Check palms and soles for hyperkeratotic lesions in reactive arthritis 2

Ocular Examination

• Anterior uveitis: Assess for eye redness, pain, photophobia, and blurred vision, as acute anterior uveitis occurs in 25-40% of ankylosing spondylitis patients 1, 5
• Conjunctivitis: Document conjunctival injection, particularly in reactive arthritis 2

Mucocutaneous Findings

• Oral ulcers: Examine oral mucosa for painless ulcers in reactive arthritis 2
• Circinate balanitis: In males with reactive arthritis, inspect for painless penile lesions 2

Cardiovascular Assessment

• Aortic regurgitation: Auscultate for diastolic murmur at left sternal border, as aortitis can occur in long-standing ankylosing spondylitis 1

Gastrointestinal History

• Inflammatory bowel disease: Inquire about diarrhea, abdominal pain, and bloody stools, as 50% of IBD patients develop spondyloarthropathy symptoms 5, 6

Disease Activity Assessment

Validated Outcome Measures

• BASDAI (Bath Ankylosing Spondylitis Disease Activity Index): Calculate score based on fatigue, spinal pain, peripheral joint pain/swelling, enthesitis, and morning stiffness duration/severity (scale 0-10) 1, 4
• Patient global assessment: Use visual analog scale (0-100 mm) for overall disease activity 1, 4
• Pain assessment: Measure nocturnal and total back pain on visual analog scale 4
• Morning stiffness: Quantify duration in minutes and severity, as prolonged morning stiffness (>1 hour) indicates active inflammation 1, 3

Functional Assessment

• BASFI (Bath Ankylosing Spondylitis Functional Index): Evaluate 10 activities of daily living to assess functional impairment 4
• Peripheral joint counts: Document number of tender joints (0-78 scale) and swollen joints (0-76 scale) 1, 4

Critical Diagnostic Pitfalls

• Do not dismiss normal inflammatory markers: ESR and CRP may be normal in up to 50% of active spondyloarthropathy cases, so clinical assessment remains paramount 1, 7
• Recognize early sacroiliitis: Plain radiographs are insensitive for early sacroiliac joint changes; if clinical suspicion is high despite normal x-rays, proceed to MRI which detects bone marrow edema before structural damage 1, 2
• Distinguish from rheumatoid arthritis: Key differentiating features include asymmetric distribution, DIP involvement, dactylitis, enthesitis, and absence of rheumatoid nodules 1, 4, 3
• Screen for HLA-B27: While not diagnostic alone, HLA-B27 positivity increases post-test probability when combined with clinical findings of inflammatory back pain and peripheral arthritis 7, 6
• Consider imaging-guided aspiration: When monoarthritis is present, perform joint aspiration to exclude septic arthritis and crystal arthropathy before attributing symptoms to seronegative spondyloarthropathy 1, 7

Monitoring Frequency

• High disease activity: Assess every 4-6 weeks after treatment initiation with clinical examination, patient-reported outcomes, and inflammatory markers 1, 7
• Stable disease: Monitor every 3-6 months with individualized frequency based on symptoms and treatment 1
• Radiographic monitoring: Obtain baseline radiographs of affected joints and spine; repeat imaging is guided by clinical changes rather than routine intervals 1