Feline thrombosis is an internal disease, and symptoms vary depending on the location of the blockage. Most cats suffer from: sudden weakness of legs and feet, paralysis of hind limbs, screams caused by pain, etc. Feline thrombosis mostly occurs in obese cats. Therefore, if you want to reduce the prevalence of feline thrombosis in your own cats, it is recommended that owners do not keep their pets too obese.