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During a busy swing shift, a 45-year-old male presents to the emergency department with two days of worsening right knee pain. He denies any injury, but states that the knee feels warm and swollen and now he can barely walk on it. He had a meniscal injury to the same knee about 8 years prior, and is now using crutches that he has left over from that time. He thinks he has gout because his brother and father have both had it with similar symptoms to his own. He denies any history of hardware in the knee, prior personal history of gout or joint infection, or any sexual exposures other than his wife of 15 years. His medical history is otherwise unremarkable and the only other surgery that he has had in the past was a splenectomy at age 18 from a motor vehicle accident.
On exam, he is an athletic male appearing younger than his stated age with a temperature of 99.4, blood pressure of 148/90, pulse of 83 and respiratory rate of 18. His head and neck exam are normal, as is his chest exam. His abdomen is non-tender with a well-healed left upper quadrant scar. The knee appears slightly swollen with a slightly reddish hue, but is not really warm. He can move it fairly decently while supine on the bed with some mild pain, but the area is fairly tender and he cannot bear weight on it.
Given the overall picture – his age, family history and the physical exam - you suspect new onset gout, but are worried that he could have a milder-than-usual presentation of a septic joint, especially since he has had prior surgery there and is minus a spleen. You therefore recommend a knee aspiration to be certain. “No way!” he answers. “I know those hurt and my brother has had those twice and they never even found any fluid. Can’t you just give me indomethacin and oxycodone like my brother gets? When he gets those, he is usually better in a few days.” You stick to your guns and answer, “Well then how do they even know that he really even has gout? The only way to tell for sure is to tap the joint. And what is more important, we need to make sure that you don’t have an infection in the knee, which would be dangerous to miss. The fact that you don’t have your spleen puts you at higher risk for infections, you know.”
Your patient appears to be pondering your words and weighing your arguments when you see his committed expression soften just a bit. He asks, “Doc, I don’t want to be a pain in the ass, and I certainly don’t want to have you give me medicine for gout if I really have an infection, but is there any way you can make sure there is fluid there so I don’t have to get stuck with a huge needle for no reason?” “Sure” you answer, “We can look at your knee with our ultrasound machine first to make sure there is a pocket of fluid to go after.” Knowing that ultrasound is more sensitive for a joint effusion than plain films, you decide to just skip the formal imaging and wheel over the department’s bedside ultrasound machine to take a peek (Image below).
What do you see? What position do you think the knee was in for this image? Is there a fluid pocket? Conclusion on next page