A 64-year-old woman comes to the physician complaining of pain in the right knee for the past day. The patient reports associated joint swelling, warmth, and redness. She says this has happened before in her knees and hips, but those episodes lasted for only a few hours and resolved spontaneously. She also reports feeling
fatigued during the past several months, but attributes this to frequently waking up at night to urinate. The patient has also had to strain more than usual when having a bowel movement and frequently takes laxatives to help.
Vital signs are within normal limits. Physical examination reveals swelling, erythema, and warmth of the right knee joint. It is tender to palpation with decreased active and passive range of motion. Laboratory studies show the following:
Arthrocentesis of the right knee is performed. Gram stain is negative. Polarized light microscopy shows
rhomboid-shaped, weakly positively birefringent crystals. Further evaluation of this patient is most likely to show which of the following?
