HCM
What is hypertrophic cardiomyopathy? Hypertrophic cardiomyopathy (HCM) is the most common heart disease of cats, whether they are random bred or pedigreed. It is a heart muscle disease in which the papillary muscles (the muscles in the left ventricle that anchor the mitral valve) and the walls of the left ventricle become abnormally thickened. HCM is often a progressive disease, and a proportion of affected cats develop heart failure if the muscle hypertrophy and subsequent scarring of the heart muscle significantly affects heart function.
What causes HCM in cats? This is currently unknown in most cats although familial (hereditary) HCM has been observed in several breeds, such as the Maine Coon and American Shorthair. Anecdotal information suggests there is familial HCM in many other breeds. Heart muscle hypertrophy in cats can be caused by other diseases, such as systemic hypertension (high blood pressure) and hyperthyroidism. HCM is a primary disease of the heart muscle. Hypertension and hyperthyroidism cause secondary thickening of the left ventricle and so are not causes of HCM (although it is possible that they may exacerbate the disease if they become present in a cat with mild to moderate HCM). HCM is diagnosed when these other causes are ruled out.
PKD
What is Polycystic Kidney Disease? Polycystic Kidney Disease (PKD) is a slowly progressive disease. It clinically shows up later in life (late onset), with enlarged kidneys and kidney dysfunction on average at seven years of age. The condition is inherited and cysts are present from birth. The size of cysts can vary from less than one millimeter to several centimeters, with older animals having larger and more numerous cysts. Problems occur when these cysts start to grow and progressively enlarge the kidney, reducing the kidneys' ability to function properly. The ultimate end is kidney failure.
Some of the clinical signs are depression, lack of or reduced appetite, excessive thirst, excessive urination and weight loss. There is a marked variability in how quickly individual cats succumb, with the possibility of the symptoms of PKD developing late enough in life that the cat can die of other causes before kidney failure. However, kidney failure is certain when and if the cysts grow and cause problems.
