Understanding Bone Scan Results: Pathologic Activity in the Left Wrist

A bone scan showing increased radiotracer uptake in the left distal radius (and possibly carpal row) indicates abnormal bone turnover at that site. This is a sensitive but non-specific finding requiring clinical correlation.

Differential Diagnosis for Focal Uptake in Distal Radius

• Fracture: Acute, stress, or occult (scaphoid, distal radius).
• Degenerative/Overuse: Osteoarthritis (radiocarpal, STT joint), tendinopathy (ECU, FCR insertion), intersection syndrome.
• Inflammatory: Rheumatoid arthritis, psoriatic arthritis, gout/CPPD deposition.
• Infection: Osteomyelitis, septic arthritis (usually diffuse, intense).
• Neoplastic: Primary bone tumor (rare), metastasis (breast, lung, prostate, kidney, thyroid).
• Complex Regional Pain Syndrome (CRPS): Diffuse periarticular uptake.
• Post-traumatic/Surgical: Recent injury, hardware, arthroplasty.
• Physiologic: Growth plate (in children), healing fracture.

Next Steps

1. Clinical correlation: History (trauma, pain pattern, systemic symptoms), physical exam (Tinel's, Phalen's, joint line tenderness, swelling).
2. Targeted imaging: X-ray (first-line), MRI (soft tissue, occult fracture, marrow edema), CT (cortical detail).
3. Labs if indicated: CBC, ESR/CRP, RF/CCP, uric acid, tumor markers.
4. Referral: Orthopedics, rheumatology, oncology based on suspicion.

Key Point

The bone scan localizes the process; clinical context and anatomic imaging define the diagnosis. "Pathological activity" is a description, not a diagnosis.