Polycystic kidney disease; cat’s life expectancy
Congenital (inherited) polycystic kidney disease is reportedly prevalent in Persian cats and, I’m told, other long-haired cats. Robert G Sherding (ed.) in The Cat: Diseases and Clinical Management published in 1989 states that the life expectancy of cats with congenital polycystic kidney disease (as opposed to acquired kidney disease) is seven years of age.
A very well-known website on kidney disease in cats (Tanya’s Comprehensive Guide) states that polycystic kidney disease (PKD) usually develops around the age of 5 to 7 years of age but cats can fall ill at two years of age. I wonder whether she is discussing acquired polycystic renal disease (not inherited) as opposed to congenital PKD. I think she is or there is conflicting information.
My earlier research also indicated that an estimated 37% of Persian cats suffer from PKD, which I’m sure you will agree is an extremely high percentage. Is also common in breeds related to Persians. Persian cats have been incorporated into many cat breeding lines. My earlier research also indicates that the disease shows up later in the cat’s life at an average of seven years of age; what is described as a late onset disease.
I’m inclined to believe that the life expectancy of cats with congenital polycystic kidney disease is often longer than seven years but for some cats it will be seven years. Bearing in mind that the average age of the domestic cat is around 18 years nowadays, seven years is a much reduced lifespan.
Robert Sherding states that cats with this disease have distended abdomens. The kidneys are enlarged and have a spongy appearance with small cortical and medullary cysts. The cat’s liver is normal in size but contains dilating cystic bile ducts. When the disease is bilateral i.e. affecting both kidneys it causes polyuria, polydipsia (increased thirst), anorexia, weight loss, lethargy and other signs of chronic renal failure.
It is not painful unless the cysts grow rapidly and rupture at end-stage PKD.