In the cat with heart disease, a sudden paralysis of the hind limbs can be the result of a blood clot thrown from a diseased heart which lodges in the artery feeding the hind legs. The feet will feel cold and the paws will look pale when compared to the front feet. Heart disease can often be treated successfully and your dog can live out its full life. I raised a dog to be 22 years old with a heart murmur. Consult your veterinarian if your pet has a persistent cough.
Dental disease is also a problem in older pets.
Both cats and dogs can have excess tartar, and abscessed teeth creating pain and loss of appetite. Your veterinarian can safely anesthetize and older pet and take care of it's dental needs. Vaccinations in the older pet are as important as they are in the young pet. Just as with older people, our older pets have aging immune systems which do not fight off bad bugs as will as when they were younger. So don't let those vaccinations become overdue.