What is the differential diagnosis of hand pain?

Differential Diagnosis of Hand Pain

The differential diagnosis of hand pain should be systematically approached by first distinguishing between articular and extra-articular causes, with joint distribution pattern, patient age, and inflammatory features guiding the specific diagnosis. 1, 2

Primary Articular Causes

Osteoarthritis (Most Common in Adults >40)

• Targets DIP joints, PIP joints, and thumb base (first CMC joint), with occasional involvement of index and middle MCP joints 1, 2
• Pain is typically usage-related with only mild morning stiffness (<30 minutes) 1
• Clinical hallmarks include Heberden nodes (DIP) and Bouchard nodes (PIP) with bony enlargement 1
• Symptoms are often intermittent, affecting one or few joints at a time 1
• Erosive osteoarthritis is a severe subtype with subchondral erosions, ankylosis, and elevated CRP 1

Rheumatoid Arthritis

• Primarily affects MCP joints, PIP joints, and wrists in a symmetrical pattern 1, 2
• Prolonged morning stiffness (>1 hour) with systemic symptoms possible 2
• Soft tissue swelling rather than bony enlargement 1
• Non-proliferative marginal erosions on radiographs are highly specific 1

Psoriatic Arthritis

• May target DIP joints or affect just one ray in an asymmetric pattern 1, 2
• Dactylitis ("sausage digit") is a hallmark feature with swelling extending along entire digit 3
• Associated warmth, erythema, and functional impairment at adjacent joints 3
• Nail involvement (pitting, onycholysis) highly suggestive 3

Crystal Arthropathies

• Gout can superimpose on pre-existing osteoarthritis with acute flares 1, 2
• Elevated serum urate and urate crystals on joint aspiration are diagnostic 1
• CPPD (calcium pyrophosphate deposition disease) has radiographic changes extremely similar to osteoarthritis 1

Hemochromatosis

• Mainly targets MCP joints (especially 2nd and 3rd) and wrists 1, 2
• Consider in patients with characteristic joint distribution and systemic features 2

Extra-Articular Causes

Tendinopathies and Tenosynovitis

• De Quervain tenosynovitis: radial-sided pain involving first extensor compartment 4
• Positive Finkelstein test with negative grind test 4
• Overuse of forearm and wrist muscles from repetitive activities 5, 4
• Intersection syndrome, stenosing tenosynovitis 5

Nerve Entrapment

• Carpal tunnel syndrome: median nerve compression with sensory changes in thumb, index, middle, and radial half of ring finger 5, 4
• Ulnar neuropathy: wrist discomfort with sensory changes in 4th and 5th digits 4
• Activities involving repetitive/prolonged wrist extension increase risk 4

Ligamentous Injuries

• Scapholunate ligament tears and lunotriquetral injuries 1
• Triangular fibrocartilage complex (TFCC) tears 1
• Often present with vague or distant history of trauma 6

Fractures

• Scaphoid fracture: most commonly fractured carpal bone after fall on outstretched hand 4
• Conventional radiography misses up to 30% of scaphoid fractures 4
• Occult fractures, chronic nonunion, or avascular necrosis 1, 7, 6

Less Common Causes

• Atypical mycobacterial infection 7
• Incomplete carpal coalitions 7
• Complex regional pain syndrome 1

Diagnostic Approach Algorithm

Step 1: Clinical Assessment

• Age, gender, joint distribution pattern, and presence of bony versus soft tissue swelling are critical 1, 2
• Duration and character of morning stiffness (mild <30 min suggests OA; prolonged >1 hour suggests inflammatory arthritis) 1, 2
• Relationship of pain to activity versus rest 1, 6
• History of trauma (acute, repetitive, or distant) 6, 4

Step 2: Initial Imaging

• Plain radiographs (posteroanterior, lateral, and oblique views) should be the first imaging study 1
• Radiographs assess joint space narrowing, osteophytes, subchondral sclerosis, cysts, erosions, alignment, and soft tissue changes 1
• In many cases, radiographs alone establish the diagnosis 1

Step 3: Advanced Imaging When Indicated

• Ultrasound (10-15 MHz linear transducers) for suspected tendon injury, tenosynovitis, nerve entrapment, or soft tissue pathology 1, 5
• MRI without IV contrast for tendinopathy, ligament tears, occult fractures, or avascular necrosis 5, 6
• CT arthrography for suspected scapholunate instability or TFCC tears (sensitivity/specificity 92-94% for TFCC, 80-100% for intrinsic ligaments) 1
• Bone scan for occult fractures (97% sensitivity, 89% specificity for scaphoid) or complex regional pain syndrome 1

Step 4: Laboratory Testing (Selective)

• Strongly positive rheumatoid factor supports RA 1
• Elevated serum urate supports gout 1
• Elevated CRP may indicate erosive OA or inflammatory arthritis 1

Critical Diagnostic Pitfalls

Avoid Single-Feature Diagnosis

• A single clinical or radiographic feature has limited sensitivity and specificity 1, 2
• Diagnosis depends on composite assessment combining age, gender, joint distribution, examination findings, and radiographic changes 1, 2

Recognize Coexistent Conditions

• Hand OA may coexist with CPPD, gout, or RA 1, 2
• Evaluate for additional inflammatory arthritides when atypical features present 2

Scaphoid Fracture Considerations

• If initial radiographs negative but clinical suspicion high, obtain specialized views (PA in ulnar deviation, pronated oblique) or repeat radiography in 10-14 days 4
• Consider bone scan or MRI if diagnosis remains uncertain 4

Chronic Pain Without Clear Diagnosis

• History and physical examination identify the cause in approximately 70% of patients 6
• Systematic algorithm using careful history, thorough examination, and simple imaging (ultrasound, scintigraphy) establishes diagnosis in 78% of cases 8
• Referral for specialized evaluation (arthrography, arthroscopy) when conservative measures fail and diagnosis remains unclear 6, 8