One of the three most common causes of death in older cats is Chronic Renal Disease. There are a wide variety of causes of this condition ranging from inherent genetic problems to infectious to cancer but all result in a slow loss of normal kidney tissue with a subsequent loss of kidney function. The kidneys are responsible for maintaining the proper hydration of the body (losing water if too much is consumed, saving water it not enough is consumed), the proper levels of electrolytes in particular sodium and potassium, removing waste, especially nitrogenous waste, from the body and a variety of other minor but important functions like producing erythropoieton (a hormone that stimulates red blood cell production). When kidney function is compromised the first ability that is lost is the ability to concentrate the urine. This results in an inability to compensate for decreased water intake which results in rapid dehydration if the cat does not increase its water intake. Since water is no longer able to be removed from the urine, urine amount increases as well. Thus, the first sign that owners notice is increased thirst and increased urination (often with accidents outside the litterbox). As kidney function worsens, electrolyte imbalances, dehydration, and buildup of nitrogenous waste quickly follow resulting in loss of appetite, lethargy, depression, and often vomiting. Weight loss and an unkempt appearance (failure to groom) are also common signs. Upon physical examination, the kidneys are small and the cat tends to be weak, thin, dehydrated, and have very dilute urine. Bloodwork shows elevated nitrogen wastes (BUN and creatinine), anemia (due to the lack of erythropoieton), and electrolyte imbalances.

Unfortunately, nothing can restore damaged kidney function. Thus, therapy is aimed at supportive care and restoring hydration, electrolyte imbalance, and removing nitrogenous wastes. Typically, by time of presentation cats with chronic renal failure will need hospitalization with aggressive intravenous fluids and electrolyte adjustments. Cats that respond to the fluid therapy can be weaned of the intravenous fluids in several days. Long-term maintenance includes a combination of subcutaneous fluids and improved oral fluid intake (thru canned food and owner encouragement via chicken broth, tuna juice, etc); a low-protein diet such as Science Diet K/D; erythropoieton injections, and regular bloodwork to ascertain nitrogenous waste levels. Many cats can live for months to a year with chronic renal failure. Eventually, though, the remaining kidney tissue deteriorates and the cat can no longer be maintained in a good quality of life.

For more information, please contact your veterinarian or email me..