De Quervain tenosynovitis is a painful, inflammatory condition caused by tendons at the side of the wrist at the base of the thumb. Pain, which is the main symptom, gets worse when the thumb is drawn out, the hand is grasped and the wrist undergoes ulnar deviation. There may also be swelling and bulging.
The most common cause is prolonged overuse of the wrist.
Activities such as golf, piano playing, fishing, carpentry or office work may cause chronic injury if the wrist is excessively used.
Most often affected by the condition are new mothers who lift up their children too often with radially outstretched thumbs and wrists passing through the ulnar to the deviation.
Repetitive grasping, holding or twisting of objects may cause inflammation of the tendon and the tendon sheaths, which causes the first interosseous compartment, restricting movement of the tendons. If left untreated, the inflammation and gradual shrinkage (stenosis) may cause fusions which further restrict movement of the thumb.
De Queverain is attributed to myxoid degeneration (a process where connective tissue is replaced by a gelatine substance) with suspension of the fibrous tissue and increased vascularity, not acute inflammation of the synovial membrane. The suspension causes swelling of the tendon sheath, which may latch onto the abductor pollicis longus and extensor pollicis brevis tendons and cause pain.