What are the causes and treatment options for joint pain in patients of various ages and demographics?

Causes of Joint Pain

Joint pain stems from two primary pathophysiologic mechanisms: inflammatory arthritis (rheumatoid arthritis, psoriatic arthritis, gout, systemic lupus erythematosus) and non-inflammatory degenerative disease (osteoarthritis), with osteoarthritis being by far the most common cause, affecting 50% of adults aged 65 and older. 1, 2, 3

Primary Etiologic Categories

Degenerative (Non-Inflammatory)

• Osteoarthritis is the predominant cause of joint pain in adults, increasing to 85% prevalence in those 75 and older 1, 4
• Characterized by brief morning stiffness (<60 minutes), bony hypertrophy, crepitus, and absence of systemic symptoms 4, 5
• Risk factors include age, female gender, obesity, muscle weakness, joint laxity, and altered biomechanics—several of which are modifiable 1

Inflammatory Arthropathies

• Rheumatoid arthritis: symmetrical polyarthritis of small joints, prolonged morning stiffness (≥60 minutes), positive anti-CCP or RF, elevated inflammatory markers 1, 3
• Psoriatic arthritis: asymmetrical inflammatory arthritis, enthesitis, dactylitis, nail dystrophy, psoriasis history, juxta-articular new bone formation 1
• Gout: most common inflammatory arthritis in men and postmenopausal women, caused by monosodium urate crystal deposition, typically presents with acute severe pain 2, 3
• Axial spondyloarthritis: inflammatory back pain, sacroiliitis, enthesitis, HLA-B27 positivity, anterior chest wall involvement in 30-60% of cases 1, 6

Crystal-Induced Arthropathies

• Gout and pseudogout result from crystal deposition (monosodium urate or calcium pyrophosphate) triggering inflammasome activation and interleukin-1β secretion 2
• Confirmation requires synovial fluid analysis demonstrating characteristic crystals 2

Infectious Causes

• Septic arthritis must be ruled out urgently via joint aspiration, as it can rapidly become lethal 2
• Consider when presentation includes fever, chills, bacteremia, significantly elevated CRP/ESR, or solitary rapidly progressive joint involvement 1

Musculoskeletal Chest Wall Pain

• Costochondritis: inflammation of costochondral junctions, accounts for 42% of nontraumatic musculoskeletal chest wall pain, presents with tenderness to palpation 6
• Tietze syndrome: localized inflammation with visible swelling, typically unilateral 6
• SAPHO syndrome: chronic relapsing condition involving sternoclavicular joints, associated with skin manifestations 6

Less Common Causes Requiring Consideration

• Fibromyalgia (neuropathic pain mechanism) 1
• Malignant bone tumors (unexplained weight loss, solitary lesion with cortical destruction) 1
• Paget's disease (elevated alkaline phosphatase, mixed osteolytic/osteosclerotic imaging, age >50 years) 1
• Chronic non-bacterial osteitis (bone marrow edema on MRI, typical sites include anterior chest wall, spine, mandible) 1

Critical Diagnostic Distinctions

Inflammatory vs. Non-Inflammatory

The single most important clinical decision is distinguishing inflammatory from non-inflammatory processes. 3, 5

Inflammatory features:

• Palpable synovitis with soft tissue swelling, erythema, warmth 5
• Morning stiffness lasting ≥60 minutes 4, 5
• Systemic symptoms: fever, weight loss, fatigue 5
• Elevated inflammatory markers (ESR, CRP) 1

Non-inflammatory features:

• Bony hypertrophy and crepitus on palpation 5
• Brief morning stiffness (<60 minutes) 4
• Absence of systemic symptoms 5
• Normal inflammatory markers 1

Distribution Patterns

• Symmetrical small joint involvement suggests rheumatoid arthritis 1
• Asymmetrical large joint involvement suggests spondyloarthropathy 1
• First metatarsophalangeal joint involvement suggests gout 2
• Distal interphalangeal joint involvement suggests osteoarthritis or psoriatic arthritis 5

Evidence-Based Treatment Approach

For Osteoarthritis (Most Common Cause)

First-line non-pharmacologic interventions are mandatory and should never be omitted: 1, 7

1. Patient education about joint protection and disease management 1, 7
2. Physical activity and exercise: most uniformly positive evidence for pain reduction 1
   • Quadriceps strengthening exercises (quad sets, short-arc and long-arc exercises) performed 5-7 times, 3-5 times daily 1
   • Aerobic fitness training (walking, swimming, Tai Chi, low-impact dance) 4, 7
   • Aquatic exercise in warm water (86°F) reduces joint loading while providing resistance 1
   • Avoid high-impact activities; rate of joint loading matters more than magnitude 1
3. Weight loss for overweight/obese patients—critical intervention 4, 7
4. Psychological interventions: uniformly positive effects on pain 1

Pharmacologic therapy (always combined with non-pharmacologic measures): 1, 7

1. Acetaminophen (up to 4 grams daily): preferred first-line pharmacologic treatment for mild-to-moderate OA pain, comparable efficacy to NSAIDs without GI toxicity 1, 7
2. Topical NSAIDs: recommended before oral NSAIDs, especially in patients ≥75 years to minimize systemic effects 1, 7
3. Oral NSAIDs: only if topical agents and acetaminophen fail; high risk of GI, renal, and cardiovascular adverse events in elderly 1, 7
4. Intra-articular corticosteroid injections: for moderate-to-severe pain or acute exacerbations with effusion 7

For Inflammatory Arthritis

Treatment requires disease-specific approaches: 1

• Physical activity and exercise remain beneficial 1
• Psychological interventions show uniformly positive effects 1
• NSAIDs for symptom control while monitoring disease activity 6
• Disease-modifying agents (e.g., immune-modulating therapy for rheumatoid arthritis) to prevent progression 1
• Education, orthotics, weight management, and sleep hygiene as adjuncts 1

For Costochondritis

1. NSAIDs as first-line pharmacologic treatment 6
2. Local corticosteroid injections to affected costochondral junctions for refractory cases 6
3. Analgesics (acetaminophen or tramadol) for residual pain when NSAIDs insufficient or contraindicated 6
4. Avoid systemic corticosteroids—no evidence supporting their use for isolated costochondritis 6

Critical Clinical Pitfalls

• Never attribute joint pain to "normal aging"—symptomatic osteoarthritis requires active management 4
• Never use medications alone without concurrent non-pharmacologic interventions 1, 7
• Always rule out septic arthritis via joint aspiration when infection is possible—can be rapidly lethal 2
• Obtain ECG in patients >35 years or with cardiac risk factors presenting with chest wall pain 6
• Morning stiffness ≥60 minutes indicates inflammatory arthritis, not osteoarthritis—requires different evaluation 4, 7
• Joint pain lasting >1 hour after exercise indicates excessive activity requiring program modification 4, 7
• Elderly patients have high risk for NSAID adverse events (GI bleeding, renal toxicity, cardiovascular events)—use lowest effective dose for shortest duration 1
• Meniscal tears on MRI are often incidental findings in patients >70 years—do not overreact to imaging without correlating symptoms 4
• Consider referred pain from hip or lumbar spine when knee symptoms present with unremarkable knee radiographs 4