My cat suddenly developed a limp in one leg accompanied with great pain which disappeared as quickly as it appeared only to transpire into another limb.The vet was at a loss, the cat was experiencing muscle wastage. I eventually 'discovered' it was limping cat syndrome, due to a virus related to the Parvo virus..and that it would simple go away..which it did and with home applied physio the cat is at 99%..My point is keep posting..it was only through the likes of these forums that info and answers are found .