Bumble foot is an ailment common in older guineapigs that occurs when the foot pad becomes infected with a bacteria or fungus and swells causing the animal pain, a grossly swollen foot, a club foot with nails bent sideways, and a slow death from blood poisoning (sepsis) in advanced stages. Cage flooring and wet bedding are usual causes for the intial onset; treatment options are very limited usually without success. Bumble foot causes the animal to bumble (walk akwardly) when walking. This condition could also descibe humans or other animals with a similar condition.
My guinea pig, Sakura Chan, at age six developed bumble foot, but lived nearly a year after developing the condition; poor baby, I miss her.