A lady presents with right knee swelling.Aspiration was done in which CPPD crystals were obtained.Next best investigation is: (A) ANA, (B) RF, (C) CPK, (D) TSH
Answer is D. Secondary CPPD deposition is associated with hypothyroid,hence TSH level should be assessed. Other conditions: Hyperparathyroidism Hemochromatosis Hypophosphaemia Hypomagnesemia Diabetes