What is the recommended diagnostic approach for a 17-year-old female presenting with fatigue and joint pain?

Diagnostic Approach for a 17-Year-Old Female with Fatigue and Joint Pain

The recommended initial diagnostic approach for a 17-year-old female presenting with fatigue and joint pain should begin with radiography of the affected joints, followed by laboratory tests to evaluate for inflammatory arthritis, and consideration of MRI if initial tests are inconclusive.

Initial Diagnostic Workup

• Plain radiographs of the affected joints should be the first imaging study to evaluate for structural abnormalities, early signs of arthritis, or other pathology 1
• Laboratory tests should include:
  • Complete blood count to assess for anemia or signs of infection 2
  • Inflammatory markers (ESR, CRP) to evaluate for inflammatory conditions 2
  • Rheumatoid factor and anti-CCP antibodies to screen for rheumatoid arthritis 2
  • Antinuclear antibodies (ANA) to screen for autoimmune conditions 2

Differential Diagnosis Considerations

Inflammatory Arthritis

• Consider juvenile idiopathic arthritis or early-onset rheumatoid arthritis, particularly if multiple joints are involved with morning stiffness lasting more than 30 minutes 1, 2
• Sjögren's syndrome should be considered, especially if there are associated symptoms like dry eyes or dry mouth 1

Non-inflammatory Conditions

• Fibromyalgia should be considered, particularly if there is widespread pain, sleep disturbances, and fatigue without objective findings on imaging 3
• Patellofemoral pain syndrome may be present if knee pain is a predominant feature, especially with anterior knee pain during squatting 4

Advanced Imaging

• If radiographs are normal or show minimal changes but symptoms persist, MRI without contrast of the affected joints is appropriate 1, 5
• MRI can detect early inflammatory changes, bone marrow edema, and soft tissue abnormalities not visible on plain radiographs 1
• Ultrasound of affected joints may complement radiographs to assess for synovitis, effusions, or tendon abnormalities 1

Special Considerations

• For suspected hip-related pain, specific radiographic views should include AP pelvic and lateral femoral head-neck views 1
• If knee pain is present, weight-bearing and patellofemoral views are recommended for optimal detection of abnormalities 1
• If symptoms suggest facet joint involvement in the spine, consider MRI of the spine 6

Important Diagnostic Pitfalls

• Avoid attributing symptoms solely to "growing pains" without thorough evaluation, as this may delay diagnosis of serious conditions 2
• Be aware that normal radiographs do not exclude significant pathology; up to 41% of osteochondral abnormalities can be missed on radiography 1
• Consider that fatigue and joint pain may represent early manifestations of systemic autoimmune diseases that require prompt diagnosis and management 1, 2
• Remember that multiple conditions may coexist (e.g., fibromyalgia and inflammatory arthritis), requiring comprehensive evaluation 3, 7

Follow-up Recommendations

• If initial tests are inconclusive but symptoms persist, consider referral to a rheumatologist for further evaluation 2
• Repeat imaging may be necessary if symptoms progress or change in character 1
• Diagnostic joint aspiration under ultrasound guidance may be considered for persistent effusions to evaluate for crystals or infection 1