What is the likely diagnosis in a construction worker with pain just distal to the base of the thumb that occasionally radiates up the forearm?

De Quervain Tenosynovitis

The most likely diagnosis is De Quervain tenosynovitis, a stenosing tenosynovitis of the abductor pollicis longus and extensor pollicis brevis tendons in the first dorsal compartment of the wrist. This condition is particularly common in construction workers due to repetitive wrist movements and hand loading 1.

Clinical Presentation and Diagnosis

The clinical picture described—pain just distal to the base of the thumb radiating up the forearm—is classic for De Quervain tenosynovitis. This condition affects the tendons that control thumb movement as they pass through a tight fibrous tunnel at the radial side of the wrist.

Key Diagnostic Features:

• Pain location: Radial wrist at the base of the thumb, often radiating proximally into the forearm
• Occupational risk: Construction workers have significantly elevated risk due to repetitive wrist flexion/extension and heavy lifting 2
• Provocative activities: Pain worsens with gripping, pinching, or thumb movements

Physical Examination:

• Finkelstein test: The gold standard provocative maneuver—have the patient make a fist with thumb tucked inside fingers, then ulnarly deviate the wrist. This reproduces the characteristic sharp pain 3
• Tenderness: Direct palpation over the first dorsal compartment (radial styloid area) elicits localized tenderness
• Swelling: May be visible or palpable over the affected tendons 3

Initial Workup

Start with plain radiographs of the wrist to rule out other pathology, though they will typically be normal in De Quervain tenosynovitis 1. Radiographs are the appropriate initial imaging for any chronic wrist pain presentation.

Ultrasound is the preferred advanced imaging modality if diagnosis remains uncertain after clinical examination. US can identify:

• Tendon thickening and inflammation
• Presence of a septum or subcompartmentalization within the first dorsal compartment (important for surgical planning if needed) 1
• Other causes of radial-sided pain like ganglion cysts

MRI is not routinely needed for De Quervain tenosynovitis but may be appropriate if multiple pathologies are suspected 1.

Treatment Algorithm

First-Line Conservative Management:

1. Thumb spica splinting: Immobilize the thumb and wrist to reduce tendon irritation 3
2. Activity modification: Reduce repetitive gripping and pinching motions
3. NSAIDs: For pain and inflammation control

Second-Line: Corticosteroid Injection

• Steroid injection relieves symptoms in approximately 72% of patients, particularly when combined with immobilization 3
• Most effective when injected directly into the first dorsal compartment
• Can be repeated if symptoms recur

Surgical Intervention:

• Consider surgical release of the first dorsal compartment for patients with:
  • Recurrent symptoms after conservative treatment
  • Failure to respond to steroid injection
  • Significant functional impairment affecting work or daily activities 3

Important Differential Considerations

While De Quervain tenosynovitis is most likely, construction workers are also at risk for:

• Thumb carpometacarpal (CMC) joint arthritis: Pain more localized to the base of the thumb joint itself, with grinding sensation and weakness with pinch. More common in older workers and postmenopausal women 2, 4, 5, 3
• Scapholunate ligament injury: Would present with more dorsal wrist pain and instability 1
• Intersection syndrome: Pain 4-6 cm proximal to the wrist where muscle bellies cross tendons
• Cervical radiculopathy (C6): Can cause thumb-sided pain but would have associated neck pain, sensory changes, and reflex abnormalities 6

Critical Pitfall to Avoid

Do not confuse De Quervain tenosynovitis with thumb CMC arthritis—both cause radial-sided thumb pain in manual laborers. The key distinguishing features:

• De Quervain: Pain over radial styloid, positive Finkelstein test, pain with tendon loading
• CMC arthritis: Pain at thumb base joint, positive grind test, radiographic joint space narrowing and osteophytes 4, 7, 5

The occupational history of construction work with repetitive wrist movements and the specific pain pattern radiating up the forearm strongly supports De Quervain tenosynovitis as the primary diagnosis 2, 8.