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Chronic Kidney Disease

  • Kidney disease is a very general term used to describe several conditions that can affect the kidneys or damage kidney cells. Some types of kidney disease are reversible. Chronic kidney disease is a progressive disease that is not curable.
  • Clinical signs associated with chronic kidney disease include increased drinking and urination, weight loss, and appetite loss.
  • Pets can sometimes experience a good quality of life for many years after being diagnosed with chronic kidney disease. Your veterinarian will evaluate your pet and discuss the best methods of disease management with you.

What Is Kidney Disease?

Kidney disease is a very general term used to describe several conditions that can affect the kidneys or damage kidney cells. If kidney disease progresses, it can eventually lead to kidney failure and death. Here are just a few medical conditions that can be associated with kidney disease:

  • Nephritis: infection of the kidneys, including the spread of systemic diseases (e.g., leptospirosis, Lyme disease) that can cause kidney damage
  • Nephrotoxicosis: damage to kidney cells associated with a drug or poison (such as antifreeze)
  • Polycystic kidney disease: a genetic condition in which kidney cells become cysts, losing their ability to function properly
  • Kidney stones
  • Heart failure (heart disease can decrease the blood supply to the kidneys, which can damage kidney cells)

The kidneys are responsible for several important functions in the body, including the following:

  • Eliminating waste products through the urine
  • Producing a hormone involved in the production of red blood cells
  • Helping to maintain the body’s fluid balance/hydration
  • Participating in the breakdown and elimination of many types of drugs
  • Helping regulate levels of important electrolytes such as potassium and sodium

Kidney disease reduces the kidneys’ ability to carry out these functions, resulting in illness and (often) further progression of disease.

How Is Chronic Kidney Disease Different?

The term kidney disease describes many conditions that can affect the kidneys. Kidney failure describes a condition in which the kidneys cannot effectively eliminate waste products, maintain hydration, and help regulate the balance of electrolytes in the blood. Despite how the term may sound, kidney failure does not mean that the kidneys stop producing urine. In fact, because the kidneys can no longer concentrate urine, increased urine production is often one of the key clinical signs associated with kidney failure. Urine production does not stop completely until kidney failure has progressed to the very end stage, which is fatal.

Kidney failure can be acute (occurring over a period of hours or days) or chronic (occurring over a period of weeks to months or longer). Antifreeze toxicosis is an example of a condition that can cause acute kidney failure. If diagnosed quickly and treated aggressively, acute kidney failure can be reversed in some cases, and the pet can go on to live a normal life.

In contrast, chronic kidney failure, or chronic kidney disease (CKD), is not reversible. CKD can be caused by conditions such as polycystic kidney disease or kidney stones, but in senior pets, it is commonly the result of an age-related decline in kidney function.

CKD tends to be progressive, meaning that it gets worse over time. Although CKD is not reversible, it is often possible to slow the progression of the disease and manage some clinical signs so that your pet is more comfortable.

What Are the Clinical Signs of Chronic Kidney Disease?

The clinical signs of CKD often start off as very mild and increase in severity as the disease progresses:

  • Vomiting
  • Appetite loss
  • Increased drinking and urination
  • Dehydration
  • Lethargy (tiredness)
  • Weight loss
  • Constipation
  • Decreased grooming
  • Drooling (due to nausea or ulcers in the mouth)

How Is Chronic Kidney Disease Diagnosed?

As with many other medical conditions, diagnosis of CKD frequently begins with your veterinarian obtaining a medical history from you. Among other things, your veterinarian may ask about any medications or supplements your pet has received; changes in appetite, drinking, or urination; previous illnesses; or any current signs of illness.

Diagnosis of kidney disease may require a combination of several tests. Your veterinarian may not recommend all of these tests, but the following are some common ones:

  • CBC and chemistry profile: These tests are commonly performed together as part of a wellness screen or initial blood testing when a pet is ill. These tests provide an overview of many of your pet’s organ systems, including the kidneys. The CBC (complete blood cell count) shows the numbers of red blood cells (needed to carry oxygen to all the body’s tissues), white blood cells (needed to help fight off infection), and platelets. Because the kidneys are involved in the production of red blood cells, pets with CKD may have low numbers of these cells. The white blood cell count may also be abnormal if infection is present. The chemistry profile measures the levels of several substances that can change if there is a problem with the kidneys, such as CKD.
  • Urinalysis: Evaluation of a urine sample from your pet can provide critical information about how well the kidneys are working. Urine that is too diluted or that contains material that should not be present can indicate that a pet may have kidney disease.
  • Radiography (obtaining x-rays): X-rays of your pet’s abdomen may show kidney stones or abnormally shaped or sized kidneys.
  • Sonographic evaluation of the abdomen: Evaluation of the abdomen by ultrasonography is a very useful test for examining the kidneys. The ultrasound machine is connected to a small, handheld probe that is held against your pet’s abdomen. The probe sends out painless sound waves that bounce off structures in the abdomen (such as the kidneys) and return to a sensor inside the ultrasound machine. This creates an image on a screen that shows your veterinarian the structure of your pet’s internal organs. The ultrasound can also “look inside” organs (like the kidneys) to detect masses, cysts, or other problems that can contribute to CKD.

How Is Chronic Kidney Disease Treated?

CKD is a progressive, irreversible condition. It is not technically “treatable” or “curable,” but in many cases, it can be well managed. Effective management generally focuses on slowing the progression of disease and improving quality of life for the patient.

Pets that are severely ill from CKD may need hospitalization and intensive care to become stable enough to continue recovering at home. At home, medications and supplemental fluids can often effectively manage the condition. There are even special diets and dietary supplements that can help some pets with CKD. Periodic blood testing and urine evaluations are often recommended to assess the pet’s response to management and determine how quickly the disease is progressing.

Pets can sometimes experience a good quality of life for many years after being diagnosed with CKD. Your veterinarian will evaluate your pet and discuss the best methods of management with you.

Although CKD is frequently not preventable, regular physical examinations and wellness screening tests can increase the chances of early diagnosis and effective management.