Kidney failure in cats

Kidney failure in cats

When it comes to our pets, we must be aware that there are a large number of pathologies that they can suffer from. From diseases to malfunctioning of certain organs are the cases that can happen. With regard to cats, they are very delicate. Any change can stress them so much that they may have to face a problem. Among them is kidney failure in cats, which we are going to talk about in this article.

First of all, if we see any abnormality in our pet, we must go to the vet. Under no circumstances should we give you medicine on our own. Many drugs that we use as humans can have negative consequences on animals, even leading to death. If we have questions, it is best to ask an expert in veterinary medicine.

Kidney failure in cats
Kidney failure in cats

kidney and urinary system

To understand kidney failure in cats we must first understand how the kidneys and urinary system work. It is a set of systems that eliminate toxic metabolites from the body. Thus, it is part of the excretory system, which includes the skin through perspiration, the respiratory tract through CO2, and the digestive system through feces. The function of the urinary system is to regulate the internal environment. To do this, it must maintain the balance of solutes in the blood, thus controlling the pH and water balance. Carnivores, including cats, have a pH between 5 and 7.

The urinary system includes the kidneys and urinary tract, which is made up of the ureters, bladder, and urethra. Both the ureters and urethra serve as storage and transport ducts. For each kidney there is a ureter that opens into the bladder, where urine is stored.

renal function

The kidneys are bean-shaped organs that are reddish-brown in color. They are in charge of filtering the blood and making urine from substances that are not needed by the body. To do this, they eliminate toxic nitrogenous metabolites and maintain a stable electrolyte balance in the body. Therefore its main functions are the excretion of waste products from the body, regulating the chemical composition of the blood, and participating in the regulation of the pH of the body. In addition, they have an active participation in endocrine function by secreting erythropoietin, which increases the activity of red blood cells. In other words: they control blood pressure, produce red blood cells and regulate the metabolism of calcium and phosphorus.

The functional unit of the kidney is the nephron. It consists of the processes of filtration, reabsorption and secretion. Due to which these organs are successful in fulfilling their main functions. The nephron is made up of several structures that perform different functions:

  • Glomerula: It is responsible for filtering water and plasma from the blood, other components such as cells or proteins are not filtered.
  • Proximal convoluted tubule: It reabsorbs water, salt, bicarbonate, glucose, amino acids, potassium, calcium, magnesium, and phosphate. In addition, there is a secretion of organic cations and anions.
  • Loop of Henle: Regulates the active secretion of magnesium ions and reabsorbs between 15% and 25% of the filtered salt.
  • Distal convoluted tubule: regulates the excretion of calcium ions and reabsorbs salts.
  • Collecting segment and cortical collecting tubule: It reabsorbs potassium ions and water mediated by antidiuretic hormone (ADH). It is also responsible for aldosterone-mediated secretion of hydrogen ions and potassium ions.
  • Marrow collecting tube: It reabsorbs salt, water and potassium.

types of kidney failure in cats

When the kidneys begin to fail, being unable to filter toxins from the blood, kidney failure occurs in cats. There are two types that can affect our pets: acute and chronic.

acute kidney failure

This pathology implies a rapid decrease in glomerular filtration. It also retains nitrogenous waste products and alters hydroelectrolyte and acid-base balance. Acute renal failure can be caused by a number of pathologies, which in turn are a consequence of others:

  • Produced by ischemic causes, hypovolemic shock or low cardiac output.
  • Tube injury, due to anesthesia or trauma.
  • Various conditions whose origin may be immune-mediated reactions, pyelonephritis, or urinary tract obstruction.

Symptoms in this case are depression, lethargy, anorexia, vomiting and tenderness. To diagnose acute renal failure, symptoms are taken into account and a urine test is performed.

chronic renal failure

The occurrence of kidney failure in cats can occur over months or even years, in which case it is called chronic. It is caused by glomerular, vascular or interstitial tubule disorders. Symptoms of the older version include lethargy, weight loss, oral ulcers, seizures, and hypothermia. In addition, it can cause polyuria and polydipsia. That is to say: the cat drinks and pees more than usual. To diagnose this pathology, a urine test should be performed.

There are different pathophysiologies that may be involved. Due to the reduced number of nephrons, the animal is not able to concentrate urine, which leads to disorders of the urinary system. This problem can be detected through a urine test, as it will show a low density. In addition, a decrease in calcium and phosphorus retention may indicate endocrine disorders. Neurological disorders can also arise due to the accumulation of nitrogenous compounds and toxins, which eventually lead to seizures. Finally, hematological changes remain to be highlighted. These include erythropoietin deficiency anemia, depressed erythrogenesis, shortened erythrocyte lifespan, leukopenia, thrombocytopenia, and coagulopathies.


Besides special medication prescribed by the vet, another way to reduce the symptoms of kidney failure in cats is by taking care of their diet. There are currently specific diets available for kidney problems. It is best to gradually change the pet’s eating habits. This will remove digestive disorders. For this, according to the recommendation of the veterinarian, the new feed should be mixed with the old one for two to six weeks.

In addition, you should avoid giving treats to the affected cat, or use a special feed for kidney problems. It is also very helpful to offer small amounts of food distributed throughout the day, rather than serving large amounts once or twice daily.