Joint pain (arthralgia) is a common musculoskeletal complaint with a broad differential diagnosis. A systematic approach is crucial for accurate diagnosis and timely intervention.
1. Comprehensive History Taking
A detailed history provides over 80% of diagnostic clues in joint disorders.
A. Pain Evaluation
| Feature | Inflammatory Arthritis | Non-inflammatory (Degenerative) Arthritis |
|---|---|---|
| Timing | Pain at rest and motion | Pain mainly during activity |
| Aggravation | Worse in the morning or after rest | Worsens with activity; relieved by rest |
| Morning stiffness | > 30–60 minutes (RA, SLE, PsA) | < 15–30 minutes (OA) |
| Onset | Gradual (RA, OA), or abrupt (gout, trauma) | Gradual or post-traumatic |
| Location | Deep (synovitis) or superficial (tendon) | Often localized to weight-bearing joints |
| Referred Pain | May radiate (e.g., hip to knee) | Less common |
B. Key Symptoms and Their Clinical Implications
- Stiffness
- Inflammatory: Prolonged, especially morning stiffness (RA, SLE)
- Degenerative: Brief, improves with movement (OA)
- Considerations: If stiffness doesn't involve hands/feet, RA is less likely.
- Swelling
- Inflammatory: Soft tissue swelling, synovitis
- Non-inflammatory: Bony enlargement (osteophytes in OA)
- Limitation of Motion
- Caused by inflammation, joint damage, or soft tissue contracture
- Often noted during daily activities (e.g., combing hair, climbing stairs)
- Weakness
- Disuse atrophy around painful joints
- Weakness with pain suggests musculoskeletal origin; without pain, consider neurological/myopathic causes
- Fatigue
- Inflammatory: Common; worse in the afternoon/evening
- Psychogenic: Fatigue on waking, linked to anxiety or poor sleep
2. Diagnostic Patterns in Arthritis
A. Temporal Pattern
| Pattern | Description | Example Conditions |
|---|---|---|
| Abrupt | Onset in hours to days | Septic arthritis, crystal arthropathy |
| Insidious | Weeks to months | RA, OA, SLE |
| Acute | < 6 weeks | Viral arthritis, trauma |
| Chronic | ≥ 6 weeks | RA, OA, Psoriatic arthritis |
B. Pain Pattern
| Type | Description | Examples |
|---|---|---|
| Migratory | Pain moves from one joint to another | Rheumatic fever, gonococcal arthritis |
| Additive | Pain persists and spreads to new joints | RA, SLE |
| Intermittent | Episodic joint involvement with symptom-free intervals | Gout, pseudogout, Lyme disease |
C. Joint Involvement
| Classification | Joints Affected | Examples |
|---|---|---|
| Monoarthritis | 1 joint | Gout, septic arthritis |
| Oligoarthritis | 2–4 joints | Psoriatic arthritis, reactive arthritis |
| Polyarthritis | ≥5 joints | RA, SLE, viral arthritis |
D. Symmetry
| Type | Features | Conditions |
|---|---|---|
| Symmetric | Same joints on both sides | RA, SLE, viral arthritis |
| Asymmetric | Uneven joint distribution | Psoriatic arthritis, reactive arthritis |
E. Joint Distribution
| Joint Involved | Indicative Condition |
|---|---|
| Distal interphalangeal | OA, PsA, gout |
| Proximal interphalangeal | RA, SLE |
| Spine involvement | Ankylosing spondylitis (lumbar), PsA |
| Sparing of spine | RA |
3. Distinctive Musculoskeletal Patterns
- Spondyloarthropathies (Ankylosing spondylitis, PsA, reactive arthritis):
- Involve axial skeleton, entheses, dactylitis (“sausage digits”), and heel pain.
- Gout and Septic Arthritis:
- Can affect joints, tendons, bursae (e.g., olecranon bursa).
4. Extra-Articular Manifestations
Clues for systemic involvement and differential diagnosis:
| System Involved | Clinical Features | Related Diseases |
|---|---|---|
| General | Fever, malaise, weight loss | RA, SLE, systemic vasculitis |
| Skin | Psoriasis, malar rash, Gottron papules, purpura | PsA, SLE, dermatomyositis, vasculitis |
| Eyes | Uveitis, scleritis, conjunctivitis | RA, AS, JIA, reactive arthritis |
| Cardiovascular | Pericarditis, conduction abnormalities | SLE, RA, vasculitis |
| Pulmonary | Pleuritis, fibrosis | RA, SLE, systemic sclerosis |
| GI/GU | Diarrhea, urethritis | Reactive arthritis, IBD-associated arthritis |
Clinical Pearls
- Monoarthritis in elderly → Consider crystal arthropathy or septic arthritis until proven otherwise.
- Symmetric polyarthritis with systemic symptoms → Think RA or SLE.
- Joint pain with rash → Check for SLE, PsA, dermatomyositis.
- Back pain in a young adult male with stiffness → Evaluate for ankylosing spondylitis.
