What are the possible causes of unilateral hand pain in a patient?

Causes of Unilateral Hand Pain

Unilateral hand pain stems from a broad spectrum of musculoskeletal, neurologic, vascular, inflammatory, and infectious etiologies that require systematic evaluation beginning with plain radiographs to identify structural abnormalities. 1

Musculoskeletal and Soft Tissue Causes

Tendon Pathology

• Trigger finger causes abnormal resistance to smooth flexion and extension ("triggering") of the affected finger, affecting up to 20% of adults with diabetes and approximately 2% of the general population 2
• De Quervain tenosynovitis involves swelling of the extensor tendons at the wrist, more common in women with median age of onset 40-59 years, and increased risk with frequent mobile phone use 2
• Tenosynovitis and tendinopathy can be identified by ultrasound, which is reasonable for evaluating tendon and soft tissue pathology of the hand 1
• Intersection syndromes represent another form of tendon inflammation detectable on MRI 1

Joint and Ligament Disorders

• Thumb carpometacarpal (basilar) joint arthritis affects approximately 33% of postmenopausal women radiographically, with approximately 20% requiring treatment for pain and disability 2
• Scapholunate and lunotriquetral ligament tears cause chronic wrist pain and can be detected with MR arthrography (sensitivity 70-87% for scapholunate tears) or CT arthrography (sensitivity 80-100%) 1
• Triangular fibrocartilage complex (TFC) tears demonstrate sensitivity of 63-100% on 3.0T MRI and 92-94% on CT arthrography 1
• Metacarpophalangeal joint collateral ligament injury and extensor hood injury are identifiable on ultrasound 1

Arthritis

• Degenerative osteoarthritis, inflammatory arthritis, and crystalline arthritis can all present with unilateral hand pain, though radiographs may show only nonspecific changes requiring clinical correlation 3
• Rheumatoid arthritis warrants rheumatology referral within 6 weeks, as early arthritis can occur with negative serologies 4
• Plain radiographs can assess alignment abnormalities, deformity, soft tissue mineralization, and calcinosis 3

Bone Pathology

• Chronic or occult scaphoid fractures can be detected with bone scan (sensitivity 97%, specificity 89%) 1
• Osteonecrosis and nonunited fractures show characteristic patterns on bone scan 1
• Malignancy requires MRI without IV contrast for optimal local staging when radiographs are suspicious 4

Neurologic Causes

Nerve Entrapment Syndromes

• Carpal tunnel syndrome (median nerve compression at the wrist) is the most common nerve entrapment, characterized by numbness and tingling in the thumb, index, middle, and radial ring fingers with weakness of thumb opposition when severe 5, 2

  • The Durkan maneuver (firm digital pressure across the carpal tunnel) is 64% sensitive and 83% specific 2
  • Electrodiagnostic testing is more than 80% sensitive and 95% specific 2
  • More common in women, people with obesity, diabetes, and those working with keyboards, computer mouse, heavy machinery, or vibrating manual tools 2

• Ulnar nerve entrapment can occur at the cubital tunnel (above the elbow) or ulnar tunnel (at the wrist), causing decreased sensation of the little finger and ulnar aspect of the ring finger with intrinsic muscle weakness 5

• Radial tunnel syndrome occasionally accompanies lateral epicondylitis ("tennis elbow") and can be differentiated with radial nerve block 5

• Ultrasound is reasonable to assess for entrapment of the median or ulnar nerves 1

Other Neurologic Conditions

• Cervical radiculopathy can produce unilateral hand symptoms and must be differentiated from peripheral nerve entrapment 5
• Thoracic outlet syndrome may cause upper extremity pain and numbness 6, 7

Vascular Causes

• Upper extremity deep vein thrombosis (UEDVT) accounts for up to 10% of all DVTs, presenting with ipsilateral upper-extremity edema, pain, and prominent superficial veins 4

  • Duplex ultrasound must be performed urgently with sensitivity and specificity above 80% 4

• Arterial insufficiency warrants upper extremity arterial testing for unilateral cold painful hand 4

• Central venous stenosis should be suspected in dialysis patients with ipsilateral extremity swelling 4

Infectious and Inflammatory Causes

• Septic arthritis and soft tissue infection require MRI without and with IV contrast to distinguish synovitis from joint effusion and to detect tenosynovitis 1
• Abscess formation can be differentiated from cellulitis, myositis, and tenosynovitis using CT with IV contrast 4
• Radiographs should be obtained first to look for soft tissue gas, foreign bodies, periosteal reaction, or bone destruction 4
• Retained foreign bodies causing infection can be identified with ultrasound 1

Occupational and Repetitive Strain Injuries

• Repetitive strain injuries develop from excessive and repetitious motions, causing microtrauma to tissues with local pain, tenderness, weakness, inflammation, and limited function 6, 7
• Physical workplace risk factors include repetition, force, duration, short cycle time, and awkward posture 8
• Epicondylitis (tennis elbow) is a common repetitive strain injury involving the elbow and wrist 6, 7

Other Causes

• Complex regional pain syndrome shows established imaging patterns on bone scan 1
• Synovitis and joint effusion can be detected with ultrasound or MRI with contrast 1, 9
• Ganglion cysts are distinguished from synovitis with postcontrast MRI 1

Diagnostic Approach

Begin with standard three-view radiographs (posteroanterior, lateral, and oblique) to assess alignment, joint spaces, fractures, soft tissue mineralization, erosions, and soft tissue swelling. 1, 3

• If radiographs are normal or show nonspecific arthritis and soft tissue pathology is suspected, ultrasound is the next appropriate study to evaluate tendons, synovitis, tenosynovitis, nerve entrapment, and fluid collections 1, 9

• MRI without IV contrast is indicated when ligament tears, TFC pathology, bone marrow abnormalities, or deeper soft tissue structures require evaluation 1

• MR arthrography or CT arthrography provide superior diagnostic accuracy for scapholunate interosseous ligament tears and early cartilage defects compared to MRI alone 1

• MRI with contrast is reserved for suspected inflammatory arthritis (rheumatoid arthritis, seronegative spondyloarthropathy) or infection to distinguish synovitis from effusion 1

• Consider duplex ultrasound urgently if vascular compromise or UEDVT is suspected based on swelling, pain, and prominent superficial veins 4