The kidneys are an extremely important organ with respect to the body's normal functioning. They filter wastes from the blood, help regulate the body's water and salt levels, play a role in regulating the blood's acidity and produce hormones responsible for maintaining red blood cell numbers and calcium balance.
Chronic kidney insufficiency is a condition where the kidneys are no longer doing their work at full capacity. The severity of the condition may vary between patients, but tends to get worse over time. Once the kidneys are no longer able to maintain the above functions on their own the condition is termed kidney "failure".
Why do cats get kidney insufficiency?
There are a number of conditions that may damage the kidneys and produce insufficiency. Drugs, toxins, infections, tumours or decreased blood flow may cause reversible and/or permanent kidney damage. In the vast majority of cases however, no underlying condition is identified.
What are the signs?
Clinical signs may be very subtle with early kidney disease. Cats may start to lose weight, be excessively thirsty and urinate more frequently. Once toxins start to accumulate in the blood the cat may go off its food, become mentally dull, have smelly breath (halitosis) and may vomit. Often cats with significant kidney insufficiency will become very dehydrated. Cats with kidney disease may also develop high blood pressure. This may cause blindness, behavioural changes or neurological signs.
How is it diagnosed?
Early kidney insufficiency can be very difficult to diagnose. Typically, changes detectable by routine blood and urine tests only become evident after a significant amount of kidney function has been lost. Tests such as urine culture and kidney ultrasound may be performed to rule out treatable conditions that may be contributing to the kidney dysfunction.
How is chronic kidney insufficiency treated?
The aim of treatment is management rather than cure. Even though some forms of kidney disease can be cured, chronic kidney insufficiency is considered an irreversible condition. The aim of management is to alleviate clinical signs and hopefully slow the progression of the condition.
Treatments may include:
Fluids delivered intravenously or under the skin to correct dehydration
Introduction of a diet low in protein to decrease the production of waste products in the blood. These diets are also low in phosphorus which may slow the progression of the disease. This may be further enhanced by the use of medications that reduce absorption of phosphorus from the gut.
Introduction of a new diet must be done slowly. Under no circumstances should a cat with kidney disease be allowed to starve in order to get it to eat the new diet. It is essential that the cat maintain an adequate food intake, even if it is not an ideal kidney diet
Supplementation of potassium
Correction of blood acid imbalances
Medication for high blood pressure
Medication for appetite stimulation and to correct nausea and vomiting
The use of benazepril (Fortekor) if there is protein loss in the urine
Injections for serious anaemia (although these may have significant side effects and are not commonly used)
It is important that cats with chronic kidney disease have regular check-ups. This enables changes in weight, blood pressure and blood test values to be picked up early. Occasional urine cultures are helpful in detecting urinary infections, which are common in cats with kidney insufficiency. Cats with kidney disease cat dehydrate very quickly, thus any changes in food and water intake or demeanour should prompt a visit to the vet.