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Monday: 8:30 a.m.-7 p.m.
Tuesday: 8:30 a.m.-7 p.m.
Wednesday: 8:30 a.m.-5 p.m.
Thursday: 8:30 a.m.-7 p.m.
Friday: 8:30 a.m.-7 p.m.
Saturday: 8:30 a.m.-2 p.m.
Sunday: Closed

What to do when our pet's kidneys fail

Many articles ago I discussed different diseases that cause our pets to drink and urinate more — kidney failure being one of them. This article delves a little more into this particular condition. Although there are many causes of kidney failure (infections, poisons, related to age), the end result is the same. Before we can discuss what happens when a kidney fails, we must first go over how a healthy kidney works.

The kidney's two main functions are to filter toxins from the blood and regulate adequate hydration. The kidneys filter the blood by sending it through a series of filters. Blood flows into the kidney through the renal (kidney) artery and into the outer portion called the cortex.

The cortex of the kidney is made up of millions of microscopic units called nephrons. Each nephron is made up of different parts that filter out toxins (byproducts of metabolism and digestion) but retain fluid.

In addition, the kidneys also have secondary functions. They help to balance calcium, phosphorus and electrolytes in the body. They produce a hormone named erythropoietin that controls and stimulates red blood cell production. Finally, the kidneys produce hormones that help to regulate blood pressure.

Most commonly kidneys decline as pets get older and they sort of "wear out" but certain infections, poisons, periodontal disease and complications of certain hormonal conditions (diabetes and hyperthyroid, most commonly) can lead to premature failure.

Luckily, the kidneys don't usually fail all at once, but rather in stages. While some of the nephrons stop functioning and scar over, others will actually increase in size and function to attempt to pick up some of the slack.

What we veterinarians used to call kidney failure is now kidney disease or kidney insufficiency in the early stages and the term failure is now reserved for the advanced to end stages of this disease.

The earliest sign or symptom of chronic kidney disease is an increase in thirst and urination (accidents in the house, urinating while sleeping, finishing a dish of water more quickly, etc).

As the disease continues, the kidney is less able to clear toxins and maintain normal electrolyte balance. This leads to a decreased appetite, weight loss, lethargy and sometimes intermittent vomiting. Chronic electrolyte and mineral imbalances can lead to muscle wasting or atrophy in conjunction with these other signs.

A definitive diagnosis of kidney disease is made by routine analysis of blood and urine. Once a diagnosis is made, additional testing such as x-rays, ultrasound, urine culture, etc. will aid in finding out the initial cause of the kidney disease.

If a specific cause can be diagnosed (such as a urinary tract infection or systemic infection that has made its way to the kidneys) then treating specifically is indicated. This can help to bring back some degree of function to nephrons that are not permanently damaged.

Overall, once a diagnosis of chronic kidney disease is made our goal is to manage it, or slow the progression. In my next article, I will discuss how veterinarians manage this disease.

Dr. Kearns has been in practice for 14 years.

matthew Kearns, DVM