MRCP2-4619

A 42-year-old woman who has taken up gardening recently complains of pain on the lateral side of her left wrist. The pain is aggravated by gripping objects tightly and using heavy gardening tools. Upon examination, there is swelling and tenderness around the lateral margin of the left wrist, extending a few centimeters proximally. Finkelstein’s test is positive. The patient’s recent FBC, UEC, LFTs, and rheumatoid factor have all been negative. What is the diagnosis?