Case presentation A 48-year-old man comes to the ED complaining of severe right knee pain for 8 hours. He states that the pain, which started abruptly at 2 AM and woke him from sleep, was quite severe, so painful that even the weight of the bed sheets on his knee was unbearable. By the morning, the knee had become warm, swollen, and tender. He explains that he prefers to keep his knee bent, and extending his leg to straighten the knee causes the pain to worsen.
He has never had pain, surgery, or injury to his knees. A year ago, he did have some pain and swelling at the base of his great toe on the left foot, which was not as severe as this episode and resolved in 2 or 3 days after taking ibuprofen. His only medical history is hypertension, which is controlled with hydrochlorothiazide. He works as a financial analyst; he is married and does not smoke but consumes one or two drinks after…
