Kidney Disease in Pets
- Kidney disease is a very general term used to describe any one of several conditions that can affect the kidneys or damage kidney cells.
- Clinical signs associated with kidney disease can vary depending on the presentation (acute or chronic) and the underlying cause.
- Pets can sometimes experience a good quality of life for many years after being diagnosed with kidney disease. Your veterinarian will evaluate your pet and discuss the best methods of treatment with you.
What Is Kidney Disease?
Kidney disease is a very general term used to describe any one of 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
- Nephrotoxicosis: kidney toxicosis; damage to kidney cells associated with a drug or poison (such as antifreeze)
- Polycystic kidney disease: a genetic condition in which functioning kidney cells undergo degeneration to become cysts and lose their ability to function properly
- Kidney stones
- Heart failure: decreased blood supply to the kidneys (secondary to heart disease) can cause kidney cell damage, leading to kidney disease
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 metabolism and elimination of many types of drugs
- Helping regulate levels of important electrolytes such as potassium and sodium
When kidney disease develops, these functions don’t occur properly, resulting in illness and (frequently) further progression of disease.
How Is Kidney Disease Different From Kidney Failure?
The term kidney disease describes many conditions that can affect the kidneys. However, kidney failure describes a condition in which kidney function decreases to such an extent that the kidneys are no longer able to 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 (not decreased) 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 terminal.
Kidney failure can occur acutely (over a period of hours or days) or chronically (usually 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. In contrast, chronic kidney failure is not reversible. Chronic kidney failure can result from a variety of causes (such as polycystic kidney disease or kidney stones), but it also commonly occurs in senior pets as a result of age-related decreased kidney functioning. The terms chronic kidney disease and chronic kidney failure are sometimes used interchangeably. These chronic kidney conditions tend to be progressive, meaning that they get worse over time. Although chronic kidney failure is not reversible, it can be successfully managed in many cases.
What Are the Clinical Signs of Kidney Disease?
The severity of clinical signs associated with kidney disease can vary depending on the presentation (acute or chronic) and the underlying cause. The clinical signs of kidney disease include the following:
- Appetite loss
- Increased drinking and urination
- Lethargy (tiredness)
- Weight loss
- Unkempt haircoat (due to decreased grooming)
- Back pain or abdominal pain (may be associated with acute kidney failure)
How Is Kidney Disease Diagnosed?
As with many other medical conditions, diagnosis of kidney disease frequently begins with your veterinarian obtaining a medical history from you. The following can help your veterinarian determine if your pet may be dealing with a kidney problem: information about any medications or supplements your pet has received; anything unusual that your pet may have eaten, drunk, or chewed; 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 tests that are frequently performed:
- 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 number 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, the numbers of these cells may be reduced if a pet has kidney disease (particularly chronic kidney failure). The white blood cell count may also be abnormal if infection is present. The chemistry profile includes several kidney values that can change if there is a problem with the kidneys, such as kidney disease or kidney failure.
- Radiography (obtaining x-rays): X-rays of your pet’s abdomen may show abnormally shaped kidneys, kidney stones, or kidneys that are enlarged or shrunken.
- 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 of 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, stones, cysts, or other problems.
- Urinalysis: Evaluation of a urine sample from your pet can provide critical information about kidney functioning. Urine that is too diluted, contains abnormal cellular debris, or contains protein and other material that should not be present can indicate that a pet may have kidney disease.
How Is Kidney Disease Treated?
Treatment of kidney disease can vary depending on the underlying cause and the patient’s overall condition. For example, if a pet has kidney stones, surgery may be recommended as the best treatment. Pets that are severely ill from kidney disease or kidney failure may need hospitalization and intensive care to recover. In other cases, antibiotics, fluids, and other medications given on an outpatient basis are effective. There are even special diets and dietary supplements that can help some pets with kidney disease.
Chronic kidney disease and chronic kidney failure are progressive, irreversible conditions. Treatment generally focuses on slowing the progression of disease and improving quality of life for the patient. Pets can sometimes experience a good quality of life for many years after being diagnosed with kidney disease or kidney failure. Your veterinarian will evaluate your pet and discuss the best methods of treatment with you.
Although kidney disease is frequently not preventable, regular physical examinations and wellness screening tests can increase the chances of early diagnosis and treatment.