Gout in the knee.

[n2doc]

17. 2 things worked for me

One was just hitting the advil as soon as my foot flared up. That helped. Keep taking it until the attack dies down. The other, which isn't something you can just do, is lithium. That really stopped it from coming back for me at least . But Lithium has its own issues, so unless you need an antidepressant, it isn't an option.

Watch what you eat as well, there are several known types of food and drink (beer, unfortunately, with me) that will instigate an attack.