Limping may be caused by a number of different things as discussed in this excellent article.
However, limping may also occur after vaccinations and some vets may not think about this as a cause of limping in your cat.
We have spent many dollars on x-rays, ultrasounds and exams before we learned that limping may occur after vaccinations. Our vets never made the connection or even suggested that as a potential cause, so if your cat has been vaccinated recently and then began limping afterward without any other apparent reason, consider that it could be limping syndrome.
Limping syndrome is caused by Feline Calcivirus Infection (FCV)
Feline calicivirus (FCV) is one of the major causes of feline infectious upper respiratory tract disease (cat flu).
Classical cat ‘flu’ follows a short incubation period of 3–5 days and consists predominantly of upper respiratory tract disease (sneezing, rhinitis, nasal discharge, conjunctivitis, ocular discharge and oral ulceration). These signs may be accompanied by pyrexia (raised temperature) and occasionally other manifestations, such as coughing and pneumonia.
From an early stage, transient lameness has also been observed as a clinical feature in some cats infected with FCV and it now seems clear that this is, in fact, a relatively common clinical manifestation of FCV infection. The transient lameness associated with FCV has acquired the name ‘limping syndrome’.
FCV was confirmed as a cause of lameness during early observations that showed kittens infected with FCV from other cats with limping syndrome developed pyrexia, depression and inappetence within 2-3 days.
Within hours of developing pyrexia, the kittens also developed generalised or localised stiffness, manifesting as shifting lameness in some, and an almost complete reluctance to move in others.
None of the cats developed sneezing or ocular discharge, but about one third developed oral ulcers (one of the classic signs of FCV upper respiratory infection).
Clinical signs were reported to resolve within 48 to 72 hours with no residual effects.
The joints were painful on touch/manipulation, and generalised hyperaesthesia (pain or hypersensitivity to touch) was present.