gouty arthritis
"Rare attacks, but when they hit, they're bad. Atypical, knee, ankle, 5th metatarsal (long foot bone behind the little toe), but always only one joint at a time, and never the big toe.  Severe pain, can't bear any weight on that side. This last time around, acetaminophen, ibuprofen, naproxen had no effect whatsoever; hydrocodone took the leading edge off but that's all.  After first dose of Prednisone, 80% pain reduction in 12 hours, remaining pain disappeared completely over the following 2-3 days."