We examined the 10-year-old cat and noticed that in addition to his hind leg coolness, his nails had a bluish tinge, and he had no pulse in his back legs. We took an x-ray and found that he had an enlarged heart, probably caused by a condition called dilated cardiomyopathy. This x-ray and the physical exam confirmed our suspicions about why Templeton's legs were so weak and cold. A blood clot had formed in the heart and was released into the aorta (the major artery running through the body). It traveled through Templeton's bloodstream until it reached the narrower arteries just above the hind legs (called the iliac arteries). There it blocked the blood flow to his legs, causing the problems. This condition is called a saddle thrombus, also referred to as a thromboembolism.
We administered pain medication and clot-dissolving drugs to Templeton and restored the blood flow in his back legs.
Even though he eventually recovered, he has not regained full use of his back legs and his owner had to get a ramp so he could get up onto his favorite spying spot. Templeton was extremely lucky; in many cases, the clot cannot be dissolved and the outcome is not as positive as it was with Templeton.
Unfortunately, cats that develop one saddle thrombus are also more likely to develop future saddle thrombi. We are hoping the best for Templeton. Although he is on medication, unfortunately, there is no way to guarantee it from happening again.
The incidence of cardiomyopathies and therefore saddle thrombi has decreased dramatically in recent years. This is because research has indicated that taurine, an amino acid, helps keep hearts healthy. These days many cat foods contain taurine. In addition, you can supplement with vitamins especially formulated for cats.
Remember, weak or dragging hind legs is a veterinary emergency. This is one of those cases where avoiding treatment can lead to permanent paralysis.