Over the last few weeks, your nine year old Bullmastiff girl has been on your mind. She is drinking more then normal and asking you in the middle of the night to let her out to urinate. That in itself is not the worry; it is the weight loss and overall lethargy that has you really concerned. The last straw was when she started vomiting – you had her into the vet the next morning for a full work up but his diagnosis floored you! How could she have chronic renal disease? How could her kidneys be so far gone and you never noticed until now?

The early stages of renal disease are hard to notice as many of the symptoms are mostly benign and can be written off as advancing age. Symptoms include:

• Drinking excess water
• Frequent urination
• Urine will not concentrate so it is pale in color with hardly any odor
• Leaking urine (more common in females)
• Vomiting
• Weight Loss
• Anorexia
• Lethargy
• Muscle Weakness

And, once blood and urine samples are run, the doctor will find:

• An elevated blood urea nitrogen (BUN) and creatinine
• High levels of protein in the urine
• Urine does not concentrate

Most owners do not notice the decline in their pet until the vomiting begins and the dog is off their food. When a dog with usually an unstoppable appetite suddenly will not eat their favorite food, alarm bells go off the unsuspecting for owners. Unfortunately, by the time symptoms begin to show, the kidneys are already working at below twenty-five percent of full function, making the alarm bells ring for the vet!

Our kidneys are the filtering system for our blood. They also produce hormones that stimulate red-blood-cell production, help regulate calcium, magnesium and phosphorous levels and keep our blood pressure within normal parameters. Kidneys are filled with thousands of tiny funnels called nephrons that work to filter and balance fluid levels in the body. When they do not work right, it affects our entire bodies, not just our urine output. Thankfully nephrons are hardy and the canine, as well as human body, come with an overabundance of these microscopic funnels and it is not until the level of functioning nephrons drops below 25% that they no longer can keep up with the physical demand of clearing out the blood of toxins and maintaining a correct fluid balance. As the level of functioning nephrons drop, the remaining nephrons cannot compensate and symptoms develop. Although, if the disease progressed slowly enough, the remaining nephrons can adjust to the higher demand placed on them.

There are two types of renal disease – chronic and acute. Chronic is the slow onset of the disease usually caused by old age and although it is not entirely reversible, the progress of the disease can be reversed to a point, slowing down the decline tremendously. Acute renal disease is usually caused by trauma, poisoning, infection, cancer and auto-immune diseases but many disorders can negatively affect the kidneys. If an animal survives a traumatic incident such as being hit by a car or falling, the next big hurdle is surviving the damage done to the kidneys when the animal went into shock. Shock kills more animals then anything else once they survive the initial incident. Reversing acute kidney failure is possible although not always, it depends on the severity of the disease and how quickly the correct treatment was implemented.

Although there are many toxins that cause acute renal failure, the most commonly seen poisonings are ethyleneglycol in antifreeze and calciferol in rat poison. As little as a teaspoon of ethyleneglycol-based antifreeze causes crystals to form inside the nephrons, shutting down renal function entirely. This is normally fatal unless treatment begins immediately i.e. owner induces vomiting after witnessing the animal lick the antifreeze. Calciferol increases the level of calcium in the body, allowing mineral deposits to develop, damaging the kidneys. There are also medications and treatment for other diseases that can damage the kidneys so always check with your veterinarian before administering anything to your pet.

Due to how insipid the onset of chronic renal failure is, most professionals recommend yearly base line urine and blood tests from age three on for big dogs, five on for small dogs. This practice can catch any kidney disease well before symptoms show as well as giving your vet an idea where ‘normal’ levels lie for your pet (base line testing is recommended for many other diseases as well, not just renal disease).

Treatment for both acute and chronic renal disease is similar and chiefly includes supporting the kidneys until they either begin to function normally once again or the remaining nephrons hypertrophy, each taking on more of the workload.

Due to the toxin levels throughout the entire body increasing, other forms of treatment can come in aiding other organs to function within normal parameters. Treatment can include medication to reduce the irritation of the lining of the stomach, antacids and phosphate binders to control mineral levels and drugs to control high blood pressure or hypertension. Other non-medicinal treatment can include sodium restriction if diet alone is not controlling blood pressure levels and introducing vitamin B complex and C to the diet to help replenish lost vitamins. Diet is an important part of treating both forms of renal failure and thankfully there are low-protein/low-phosphorous diets available through your veterinarian. Encouraging the dog to drink is a vital part of the healing process – dogs suffering from any form of renal disease should have clean, fresh water available at all times.

Kidney problems in dogs are common and serious but with quick treatment and a change in lifestyle, many dogs can continue to lead long, normal and happy lives. Have your dog tested next time you take him in for vaccines and know that forewarning is the best way to ensure your companion is at your side for years to come.