Kidney failure and disease in dogs

What is kidney disease in dogs?

Many important tasks are carried out by the kidneys when they are functioning normally. They remove toxins from the blood and excrete them from the body in urine, regulate blood pressure and blood acidity levels, as well as preventing water loss and maintaining an overall healthy metabolic balance. Any condition which stops the kidneys working properly is referred to kidney or renal disease, and can vary greatly in severity. It means damage is in progress but there is still functional tissue left. In renal failure, the kidneys have stopped working altogether and is far more serious. 

Kidney disease is classified in two ways; acute and chronic.

When the condition is acute, it is a complication of another condition such as kidney stones or cancer, or the consumption of something toxic. In this case, symptoms can be severe and onset rapidly but, depending on the cause, the condition can sometimes be treated and resolved.

Chronic renal disease is an irreversible long-term condition which progresses gradually over time. But, because dogs have much more kidney tissue than is essential for day to day life, chronic disease can also appear to start suddenly because symptoms often only show when a lot of damage has already happened. Although there is no cure for chronic renal disease, early intervention can sometimes limit the damage done to the kidneys and slow the progression of the disease. Chronic renal disease is normally caused by a primary malfunction of the kidneys and not another illness or toxicity, although acute renal failure can sometimes develop into a chronic form of the condition.

What causes renal disease in dogs?

There are many different causes of kidney disease in dogs. Certain breeds are more susceptible to the condition and it can often be genetic. Age has a bearing on renal functionality, and environmental factors can also damage the organs, such as chemicals, toxic foods, infections and some medications. Kidney problems in dogs can also be caused by illnesses such as cancer. It’s even suggested that advanced dental disease has a link with renal failure.

What are the symptoms of kidney disease in dogs?

Symptoms of renal failure in dogs can vary dramatically between cases because the kidneys are responsible for so many functions within the body. Symptoms can appear suddenly or progressively, and can include any of the following:

• Drinking excessively and urinating more frequently. It often seems strange to pet owners that a pet which is urinating a lot can have renal problems but it’s because the kidneys lose their ability to conserve water
• Soiling in the home due to the larger volumes of urine
• Vomiting
• Diarrhoea
• Loss of appetite
• Weight loss
• Pale gums (caused by anaemia)
• Ulcers in the mouth
• Overall weakness or dullness
• Sudden blindness due to high blood pressure
• Fragile bones

But remember, most of the above symptoms can be caused by other conditions which are less serious. However, if symptoms do arise, it’s important to take your dog to see the vet as soon as possible as early treatment is vital if kidney disease is detected.

Diagnosing kidney disease in dogs

Blood and urine samples are normally the first tests done to diagnose renal failure in dogs, as both can show up abnormalities linked to the condition. It can often take a lot of kidney damage before routine tests can show traces of the disease, but newer tests are now appearing which offer the chance of earlier detection. Elevated blood pressure is often found in dogs with chronic kidney disease, so is also a useful indicator, although it does have many other causes. Ultrasound or X-rays may be used so that your vet can take a look at your dog’s kidneys – the organs can often change in size and appearance when a pet is suffering from renal failure.

Once a dog is diagnosed with kidney disease, vets may asses their blood to stage the condition to help determine treatment. It goes from stage I, where pets show evidence of disease but no change in kidney function, to stage IV, where the condition is making the dog unwell.

How is renal disease in dogs treated?

Treatment will depend on how advanced your dog’s kidney disease is, but can include:

Diet

Diet is the cornerstone in managing kidney disease. A specially formulated diet for patients can often help, as can individually-tailored diets such as those low in protein, phosphorus, calcium and sodium but high in omega 3 fatty acids. But recommended changes in diet will depend on the stage of renal disease in your dog, so you’ll need advice from your vet before making any adjustments. Unfortunately, the lack of protein in diets for kidney disease in dogs can often make food unappealing to them and it’s important to ensure your pet continues to eat. Keeping your dog well hydrated is also crucial, so always ensure they have a supply of clean water. It’s best to have lots of water bowls in different locations.

Medication

As renal disease can affect so many different bodily functions, a huge variety of medications are available to treat each dog’s symptoms, whether primary or secondary – from eye problems to sickness. Supplements can also be used to replace vital vitamins lost in kidney disease patients, and phosphorus binders and vitamin D supplements can be used to try to reduce some of the secondary effects of renal disease by improving calcium and phosphorus balance. Medications can vary depending on the stage of the condition and the symptoms your dog is showing. Always be guided by your vet as the wrong supplement can be harmful.

Fluid therapy

To help reduce dehydration resulting from renal disease and kidney failure, fluid therapy can be used to replace depleted body fluid levels and help the kidneys flush out the toxins in the body. This can be given through an intravenous drip or subcutaneously (injected under the skin).

Kidney dialysis

In cases where all other treatment options have been exhausted, a vet may recommend kidney dialysis to further prolong or enhance your dog’s life. Like in humans, it involves a machine which takes in the dog’s blood and cleanses it before pumping it back into the body.

But this is not common practice as it is only offered at a small number of specialist centres, and can be very expensive - especially since around three sessions will be needed every week and it will never cure the condition. Furthermore, it is not without risks of its own and not all patients respond to the treatment.  

Can kidney disease in dogs be prevented?

As kidney disease can be inherited, responsible breeding can play a role in preventing the chronic form of the disease. Many acute cases of the condition can also be prevented by keeping pets away from toxic substances like antifreeze and rat poisons, as well as certain foods including raisins, grapes and some plants. The infectious disease, leptospirosis, can cause kidney disease so it's important to keep vaccinations up to date.

A balanced, species-appropriate diet will also supply your pet with the fundamental nutrients needed for their body, which will give your dog the best chance of staying healthy. Perform regular health checks on your dog at home and contact your vet promptly if your pet seems unwell, is drinking more or losing weight. Always take them to your vet for an annual health check to ensure any signs of disease can be spotted as soon as possible.