What is Chronic Kidney Disease in Dogs?

Introduction

Over the past few weeks, Helen had become increasingly concerned about her beloved senior Labrador Retriever, Daisy, who seemed to be losing her appetite and becoming increasingly lethargic. Daisy was also drinking water excessively and urinating more frequently than usual. Worried about her furry companion’s health, Helen scheduled an appointment with their trusted veterinarian. After a comprehensive examination and several diagnostic tests, the vet revealed that Daisy was suffering from chronic kidney disease, a condition that Helen had never encountered before.

Chronic kidney disease in dogs (CKD) is when the kidneys fail over time due to damage or scarring. The most common cause of CKD is diabetes, but many other reasons include hypertension, glomerulonephritis, amyloidosis, polycystic kidney disease, and others.

There are two types of CKD: acute and chronic kidney failure. Acute kidney failure occurs when the kidneys suddenly stop working correctly. This usually happens after surgery or trauma. Patients who suffer from this type of kidney failure may need dialysis or a transplant.

Chronic kidney failure is not life-threatening, but it does require ongoing treatment. Kidney disease stages: Stages 1, 2, and 3. Each step requires different treatments.

• Stage 1: Mildly decreased kidney function. This stage occurs when the dog begins losing weight. This is called prerenal azotemia. Treatment includes diet modifications, blood pressure control, and medications.
• Stage 2: Moderately decreased kidney function. This involves a rise in creatinine levels. This is called renal azotemia. This stage often goes unnoticed until patients develop symptoms like fatigue, shortness of breath, nausea, vomiting, and diarrhea. Treatment includes dietary adjustments, medication, and dialysis. Dialysis is a process of filtering waste materials out of the bloodstream through a machine called a hemodialyzer.
• Stage 3: Severely decreased kidney function. Nitrogen levels in urea rise; this is called hyperazotemia. This stage is characterized by severe fluid retention and swelling. Patients must be treated with dialysis and possibly a transplant.

Dog’s Kidney – What Do They Do?

Dog’s kidneys are organs located at the bottom of the abdomen. They filter blood and remove waste products. The kidney comprises two main parts: the cortex (the outer part) and the medulla (the inner part). The cortex contains many tiny tubes called nephrons. Each nephron filters out waste products such as urea and creatinine. These wastes then pass into the tubules, carrying them away through urine.

In dogs, the kidneys produce approximately 1 liter of urine per day. This amount varies depending on the size of the animal. Smaller breeds may only produce 0.5 liters of urine daily, while larger species may produce 2 liters.

Causes of Renal Failure in Dogs

There are several different types of canine chronic kidney disease. Some dogs develop CKD after being diagnosed with diabetes mellitus, hyperthyroidism, obesity, genetic disorders, or other conditions.

Other dogs develop CKD without having any of those conditions. Some dogs never show signs of CKD until they die.

Regardless of the type of CKD, the leading cause is a chronic inflammation of your dog’s kidneys, known as glomerulonephritis. This happens when your dog’s immune system attacks his own body. Other causes include congenital disabilities, metabolic disorders, bacterial infections, toxins, immune system diseases, and cancer.

This attack damages the tiny filters inside your dog’s kidneys. These filters remove waste products from your dog’s bloodstream. They also regulate the water and minerals he gets from food and drinks.

When the filters stop working correctly, waste builds up in your dog’s bloodstream. The waste eventually goes through the rest of your dog’s body. Your dog’s kidneys try eliminating the trash but can’t handle the extra load. Finally, they become damaged and stop functioning.

Some dogs develop CKD slowly over the years. Others experience rapid deterioration. Regardless of the speed, once your dog develops CKD, it’s almost impossible to reverse. For older animal populations at veterinary care facilities, CKD affects up to 10% of dogs and 35% of cats, but that number is lower for the general population.

Symptoms of Chronic Renal Failure in Dogs

When dogs develop chronic kidney disease, they often experience clinical signs, including weight loss, less water consumption, diarrhea, lethargy, poor appetite, and depression. These symptoms can occur gradually or suddenly.

As long as your dog has access to water, he shouldn’t lose too much weight, so always have extra water. However, if his appetite decreases, he may eat less. This can lead to dehydration.

Diarrhea is another symptom of chronic kidney disease. Dogs suffering from this problem may have loose stool or bloody stools. They may also vomit frequently. As a result, your dog may experience lethargy, lying down more often, sleeping, and exercising longer.

Decreased appetite is another symptom to look out for. Sometimes, owners report that their dogs refuse food altogether. Some dogs also become withdrawn and depressed. Others become aggressive and destructive. Other clinical signs of chronic kidney disease include vomiting, increased thirst, and urination.

Diagnosis of Chronic Kidney Disease in Dogs

Clinical diagnosis is based on physical examination, laboratory tests, urinalysis, radiographs, and ultrasound imaging. However, there are some things that doctors look for when diagnosing CKD. These include blood pressure readings, proteinuria, decreased urine output, elevated creatinine levels, abnormal liver function tests, swelling of legs or ankles, fatigue, weight loss, and bone pain.

• Physical exams check for abnormalities in the eyes, ears, nose, mouth, skin, gums, teeth, abdomen, genitals, and rectum. In addition, the vet checks for swelling in the legs or feet, diarrhea, vomiting, lethargy, weight loss, coughing, sneezing, breathing difficulties, and other clinical signs.
• Laboratory tests measure the amount of protein in the blood, blood flow, cholesterol levels, electrolytes, glucose, calcium, phosphorus, albumin, globulin, bilirubin, urea nitrogen, creatinine, urine protein, alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferases.
• Urinalyses are used to analyze the color, consistency, odor, presence of crystals, sedimentation rate, pH level, specific gravity, bacteria count, and red blood cell production.

• Radiographs are taken to examine the kidney’s size, shape, density, and structure.
• Ultrasounds view internal structures such as the heart, lungs, spleen, pancreas, gallbladder, liver, kidneys, bladder, uterus, ovaries, testicles, lymph nodes, and thyroid gland.

Once the vet determines that the dog has kidney disease, they may recommend treatment options such as medication, surgery, dialysis, or transplantation.

Treatment for Canine Kidney Failure

Treatment options for CKD depend upon the underlying cause. For example, if the primary problem is diabetes mellitus, then dietary management may be sufficient. However, additional treatment may be required if there is evidence of contemporary issues such as proteinuria, azotemia, or hypertension.

• Dietary management includes reducing the intake of carbohydrates and increasing the consumption of lean meat, fish, eggs, and low-fat dairy products. In addition, low-phosphorus, low-sodium, and low-protein prescription diets for dogs with kidney disease have improved their health and extended their lives.

Additional treatments include insulin therapy, angiotensin-converting enzyme inhibitors, calcium channel blockers, potassium-sparing diuretics, and antihypertensive medications.

• Dialysis is usually recommended for dogs who experience severe clinical signs of CKD, including those with very high creatinine levels. It involves removing waste products from the bloodstream through a machine. Dialysis is used when medical treatment has failed, but the chances of dying without dialysis are almost 100%. It does not cure CRF but helps control symptoms until a patient receives a transplant. This is typically performed three times per week. Some patients require daily dialysis.

There are two types of dialysis: hemodialysis (HD) and peritoneal dialysis (PD). HD uses a particular kind of blood vessel called a fistula to connect the vein and artery of the arm. PD uses a catheter inserted into the abdomen. Both methods remove excess water and toxins from the body.

After dialysis, patients return home with instructions on monitoring their health and adjusting medications.

• Transplantation is often used for dogs who have mild to moderate CKD. Transplants are performed after the patient has been treated with immunosuppressive drugs for several months. These medications help prevent the rejection of the transplanted organ.

Prevention of Chronic Kidney Disease in Dogs

So, what can you do to prevent your dog from developing CKD?

1. Watch your dog closely for symptoms of CKD. Your vet may recommend blood tests to check your dog’s levels of creatinine and urea nitrogen (also called BUN). These tests measure the level of waste in your dog’s blood. If your dog’s levels are high, then he likely has CKD.
2. Make sure your dog eats a healthy diet. Food rich in protein and phosphorus is linked to higher levels of waste in your dog. So, avoid foods such as red meat, poultry, dairy, fish, eggs, and shellfish. In addition, limit your dog’s intake of table salt. Table salt contains sodium chloride, which increases your dog’s urine output.
3. Make sure your dog gets plenty of exercises. Exercise boosts your dog’s metabolism, which burns calories. Burning calories reduces your dog’s chances of getting overweight.
4. Make sure your dog receives regular veterinary care. Regular visits to your veterinarian can detect early kidney issues. Early detection means better treatment options.
5. Consider adding supplements to your dog’s diet. Supplements can help improve your dog’s overall health. For example, omega-3 fatty acids in salmon oil can boost your dog’s immunity.
6. Take steps to reduce stress in your life. Pressure can increase your dog’s risk of developing CKD. So, spend less time worrying and more time enjoying life.

Frequently Asked Questions