A 63-year-old man presents to the emergency room with severe pain and swelling in his right knee. The pain started suddenly, and there is no history of injury to the knee. On physical examination, the knee is warm, red, and swollen with decreased range of movement. A diagnostic aspiration of the knee is performed. Which of the following will most likely distinguish pseudo-gout from gout?
Pseudogout (calcium pyrophosphate crystals - CPPD) is distinguishable from gout by positive birefringent crystals. CPPD are short, blunt rhomboids, and urate crystals (seen in gout) are needle-shaped with negative birefringence.
positive birefringent crystals
acute onset
involvement of single joints
involvement of large joints
Immunology and Rheumatology