Kidney Disease in Persian Cats

Polycystic kidney disease (PKD) is a condition that causes cysts, or pockets of fluid, to form in a cat's kidneys. Kittens are born with the disease, but the cysts grow slowly, so most cats show no sign of the disease until between 3 and 10 years of age. Though the disease has been diagnosed in British shorthairs, exotics, Scottish folds and Himalayans, it is most prevalent in Persian and Persian-cross cats, which makes the disease especially troubling to Persian cat owners and breeders.

  1. Facts

    • Persians cannot "catch" PKD from other cats. It is an inherited disease that one or both parents pass to their offspring. Cysts are present from birth but grow larger over time until they cause kidney failure. The disease is irreversible and eventually leads to death.

    History

    • Feline polycystic kidney disease was first reported in 1967. No thorough research was conducted until 1990, when a 6-year-old Persian female with large kidneys and symptoms of renal failure was taken to the Ohio State University hospital. She was diagnosed with PKD, and her offspring were used to conduct further research.

    Significance

    • Though many breeders have adopted screening practices before breeding, the delay in symptoms means an affected cat may produce many litters of affected kittens before it becomes ill. Research shows that one in three Persians is affected by PKD worldwide, but some researchers estimate that 50 percent of Persian cats in the U.S. are or will be affected by polycystic kidney disease.

      Polycystic kidney disease in Persian cats is also important to the medical community because it resembles autosomal dominant polycystic kidney disease (ADPKD) in humans. Because of this, it is a valuable animal model of the human disease.

    Identification

    • Cysts are larger and easier to detect in older Persians, but professionals can use an ultrasound to diagnose PKD in six- to eight-week-old kittens. An ultrasound after about 10 months old is 98 percent accurate in diagnosis. Kidney failure is usually diagnosed through urinalysis or a blood chemistry panel. There are many causes of kidney failure, though, so an ultrasound is still the best way to determine if a cat has PKD. Owners can also use DNA testing to see if their Persians may be at risk for polycystic kidney disease. When diagnosis occurs only after renal failure, it is often too late to save the cat.

    Effects

    • As cysts develop in the Persian cat's kidneys, the cat loses normal kidney tissue and the kidney is less able to function normally. When the cat's kidney function drops too low, kidney failure occurs. Persians with kidney dysfunction may experience depression, lack of appetite, extreme thirst, excessive urination, poor hair coat and weight loss. Some may also experience vomiting or diarrhea, high blood pressure or nervous system problems like blindness or seizures.

    Treatment

    • More research is needed to understand the underlying causes of PKD and develop better treatments. Polycystic kidney disease currently cannot be treated, and the small size and sheer number of the cysts makes surgical removal impractical. However, Persians can be treated for kidney failure, which may improve the cat's quality of life. The most common treatments for kidney failure are increased fluids, potassium- or calcium-rich diets, low-phosphorous diets or certain medications, such as metoclopramide or famotidine.

    Prevention/Solution

    • The most effective way to prevent the spread of polycystic kidney disease in Persian cats is to screen cats before they are bred, and then neuter or spay infected cats to keep them from passing the disease to their offspring. Since an ultrasound can detect PKD before cats reach breeding age, breeders may be able to reduce or eliminate the disease entirely through selective breeding programs.