An 82-year-old woman had sudden onset of pain and swelling in her left knee

An 82-year-old woman had sudden onset of pain and swelling in her left knee. Th ere was no trauma. She had no previous episodes or history of fever. She was taking hydrochlorothiazide for hypertension. Joint aspiration analysis is negative with Gram staining, the synovial fl uid leukocyte count is 12.5 × 10 9 /L, and polarization microscopy shows weakly positive rhomboid birefringent crystals. Laboratory study results include the following: hemoglobin 11.7 g/dL, leukocyte count 7.2 × 10 9 /L, erythrocyte sedimentation rate 45 mm/h, creatinine 1.6 mg/dL, and uric acid 8.6 mg/dL (reference range cause of her acute monoarthritis? a. Gout b. Pseudogout c. Basic calcium phosphate disease d. Calcium oxalate arthropathy e. Septic joint