What is the most likely diagnosis and initial management for a stable patient with normal vital signs who reports diffuse pain, most severe on the dorsal aspect of the left hand near the thumb, without recent trauma, swelling, warmth, or focal tenderness?

Diagnosis and Management of Dorsal Hand Pain Near Thumb Base

Most Likely Diagnosis

The clinical presentation most strongly suggests de Quervain tenosynovitis, given the localization to the dorsal radial aspect of the hand near the thumb base, absence of trauma, and presence of swelling, warmth, and tenderness. 1, 2, 3

Differential Diagnoses to Consider

The dorsal thumb base location requires systematic evaluation for several conditions:

• De Quervain tenosynovitis - inflammation of the first dorsal extensor compartment tendons (abductor pollicis longus and extensor pollicis brevis), presenting with radial-sided wrist/hand pain, swelling, and tenderness 1, 2, 3
• Thumb carpometacarpal (CMC-I) osteoarthritis - typically presents with pain at the base of the thumb, though usually without acute warmth unless experiencing inflammatory flare 4, 2, 5
• Occult dorsal ganglion cyst - the most common cause of dorsal wrist pain (76% in one MRI study), though typically without warmth 6
• Thenar compartment syndrome - rare but critical diagnosis presenting with thenar eminence firmness, pain worsened with movement, and potential neurovascular compromise 7
• Scaphoid fracture - must be excluded even without reported trauma, as 30% can be missed on initial radiography 3

Critical Physical Examination Maneuvers

Perform these specific tests to differentiate diagnoses:

• Finkelstein test - patient makes fist with thumb tucked inside fingers, then ulnar deviate the wrist; positive if reproduces pain over first dorsal compartment (diagnostic for de Quervain) 2, 3
• Grind test - axial compression and rotation of thumb metacarpal; positive suggests CMC arthritis, negative helps confirm de Quervain 2, 3
• Assess thenar compartment - palpate for firmness/tenseness of thenar eminence, check capillary refill and sensation in thumb/index finger to exclude compartment syndrome 7
• Palpate anatomic snuffbox - tenderness suggests scaphoid fracture even without trauma history 3
• Assess for joint effusion - presence suggests intra-articular pathology rather than tendinopathy 1

Imaging Strategy

Plain radiography should be obtained initially to exclude fracture and assess for CMC arthritis, with specialized views if scaphoid fracture suspected. 3

• Posteroanterior, lateral, and oblique views of the hand/wrist 3
• If scaphoid fracture suspected: add posteroanterior in ulnar deviation and pronated oblique views 3
• MRI is warranted if diagnosis remains unclear after initial evaluation, as it identifies dorsal pathology in 84% of cases with dorsal wrist pain 6
• Repeat radiography in 10-14 days or bone scan/MRI if scaphoid fracture cannot be excluded but initial films negative 3

Initial Management Algorithm

First-Line Conservative Treatment (Start Immediately)

Begin with activity modification, immobilization, and topical NSAIDs as first-line therapy for presumed de Quervain tenosynovitis or early CMC arthritis. 4, 2

• Activity modification - avoid repetitive thumb/wrist movements and gripping activities 4, 8
• Thumb spica splint - immobilize the thumb and wrist, particularly effective when combined with other treatments 4, 8, 2
• Topical NSAIDs (e.g., diclofenac sodium 2% solution) - apply twice daily to affected area; provides efficacy with lower systemic exposure than oral agents 4, 8
• Heat application - paraffin wax or hot packs before exercise for symptomatic relief 4, 8
• Elevation - elevate hand to reduce swelling 1

Second-Line Pharmacological Management

If inadequate response to topical therapy after 1-2 weeks:

• Acetaminophen up to 4g daily - first-choice oral analgesic due to safety profile 4, 8
• Oral NSAIDs at lowest effective dose for shortest duration if acetaminophen insufficient 4, 8, 9
  • Naproxen 375-500mg twice daily is effective for musculoskeletal pain 9
  • Mandatory proton pump inhibitor co-prescription for gastrointestinal protection 4
  • Assess cardiovascular and renal risk factors before prescribing 4, 9

Third-Line Invasive Treatment

Corticosteroid injection provides approximately 72% symptom relief for de Quervain tenosynovitis, particularly when combined with immobilization. 8, 2

• Inject into first dorsal compartment for de Quervain 8, 2
• Target CMC joint if arthritis confirmed 4, 8
• Consider earlier injection if symptoms significantly impact function 8, 2

Fourth-Line Surgical Referral

Surgical release should be considered when conservative treatments have failed and the patient has marked pain and/or disability affecting quality of life. 4, 10, 8, 2

• For de Quervain: release of first dorsal extensor compartment 8, 2
• For CMC arthritis: interposition arthroplasty, osteotomy, or arthrodesis 4, 10
• Critical timing: refer before prolonged functional limitation develops, as delayed treatment leads to worse outcomes 4, 10

Red Flags Requiring Urgent Evaluation

• Firmness/tenseness of thenar eminence with pallor, poikilothermia, or paresthesias - suggests compartment syndrome requiring emergent surgical decompression 7
• Progressive neurologic symptoms - may indicate nerve compression requiring urgent intervention 3
• Signs of infection - erythema, warmth, systemic symptoms require consideration of septic arthritis or cellulitis 1

Common Pitfalls to Avoid

• Do not delay surgical referral once conservative management has clearly failed - established functional limitation leads to worse outcomes 4, 10
• Do not miss compartment syndrome - acute hand pain with thenar firmness requires immediate surgical consultation 7
• Do not rely solely on initial radiographs to exclude scaphoid fracture - up to 30% are missed on conventional radiography 3
• Do not prescribe oral NSAIDs without gastroprotection - mandatory PPI co-prescription required 4
• Do not use first-generation cephalosporins, macrolides, or clindamycin if infection suspected - these have poor activity against common hand pathogens 1

Monitoring and Follow-Up

• Reassess within 24-48 hours if symptoms worsen or new neurologic symptoms develop 1
• If on oral NSAIDs: monitor cardiovascular, gastrointestinal, renal, and hepatic function based on individual risk factors 4, 9
• Check hemoglobin if prolonged NSAID use planned 9
• If no improvement after 3-6 months of conservative therapy, proceed to surgical consultation 1, 4, 10