Kidney failure in cats - Symptoms and treatment


Chronic renal failure, also called renal failure, is one of the most common diseases in older cats. In most cases, renal failure is progressive so that there is a gradual progression of the disease and a worsening of symptoms. The degree of disease progression varies considerably from one individual to another. Proper care and treatment can increase the quality of life of affected cats and prolong their life, slowing the progression of the disease.

What causes chronic renal failure?
Chronic renal failure occurs when there is prolonged and irreversible kidney damage, which prevents its functionality to filter and eliminate waste products from the blood. In the majority of cases in which renal failure is diagnosed, the exact cause of the disease is unknown. Samples taken from affected kidneys (biopsies) usually show a large amount of fibrous tissue replacing normal kidney tissue, often with some inflammation (that's why it is also called "chronic interstitial nephritis"). These changes also affect many diseases. However, there are some well-recognized causes of chronic renal failure such as the following:

    Polycystic kidneys (hereditary disease that usually occurs in Persian and Exotic cats in which cysts full of fluid> In most cases a specific cause of renal failure cannot be found and one acts with symptomatic treatment. When the cause is found , and this can be treated, there could be the possibility of slowing the progression of the disease.

Is kidney failure very common?
Chronic renal failure can occur in cats of all ages, but is usually seen in cats of middle and old age, and is more common as age increases. It is estimated that about one in 5 cats over 15 years of age has renal failure. In general, renal failure, occurs up to three times more in cats than in dogs.

What is the function of the kidneys?
The kidneys perform a wide variety of important functions, including the elimination of toxins from the blood and the maintenance of the body's water and electrolyte balance. Blood is constantly filtered through the kidneys to eliminate waste toxins from the body's metabolism products. Urine is produced in this process. The kidneys also concentrate urine by returning water to the body, to prevent dehydration.

The kidneys fulfill other important functions in maintaining the electrolyte balance (potassium, sodium, calcium, phosphorus, etc.) in the body, regulate the acid content of the blood and control blood pressure. They are also responsible for the production of the hormone called erythropoietin that stimulates the production of red blood cells by the bone marrow.

Fortunately, there is a good "reserve capacity" in the kidneys, so that if one of them were removed, (for a transplant, for example) there would be no adverse consequences. In fact, they need to be damaged from two thirds to three quarters of the functional tissue of the kidneys so that signs of renal failure occur.

What are the symptoms and complications of chronic renal failure?
In most cases chronic renal failure is a disease of slow and insidious progression, although in certain cases the symptoms may appear suddenly. Most of the symptoms are quite vague and nonspecific, produced, at least in part, by the accumulation in the blood of toxins that are usually secreted in the urine. The most common symptoms we find in affected cats are: lack of appetite, weight loss, dehydration, lethargy and depression. They are usually very thirsty and produce much more urine (due to the inability to concentrate it). Other symptoms may be: damaged fur, vomiting, halitosis, mouth ulcers and weakness. As renal failure progresses (regardless of treatment) these symptoms tend to get worse over time.

Due to the diversity of functions performed by the kidney, numerous complications may occur in affected cats, such as electrolyte balance abnormalities (for example: low blood potassium concentration, high phosphorus concentration), retention of excessive acid content in the body (acidosis), elevated blood pressure (hypertension) and anemia (low number of red blood cells).

How is renal failure diagnosed?
The symptoms of renal failure are non-specific. They may be the same as those that cause other diseases. The diagnosis, therefore, will be made by a blood test and a urine test. Two substances in the blood are usually analyzed: urea and creatinine, since these are the products of metabolism that are normally excreted by the kidney. In a renal failure the concentration of these two parameters increases. Because there are other diseases that can also increase these values, a urine test is performed at the same time. In chronic renal failure, in addition to the symptoms and elevated values ​​of urea and creatinine, poorly concentrated urine will be produced. To assess the concentration of urine, the "specific gravity" of the urine is measured, the value of which in most cats with renal failure is less than 1,030.

How is kidney failure treated?
In cases where the specific cause of renal failure is found (for example: bacterial infection in kidneys), the cause can be directly treated. But in most cases it is not so and, therefore, the treatment focuses on the symptoms. Some cats will initially need intravenous fluid therapy to correct dehydration (and probably electrolyte abnormalities). Once stabilized, the treatment will be aimed at maintaining renal function and minimizing complications of renal failure. Chronic renal failure is irreversible and, in most cases, no improvement will be achieved despite appropriate treatment.

Appropriate treatments will require periodic checks at different times (including blood pressure measurements and blood and urine tests) to identify complications that may arise and be able to treat them, such as anemia (decreased red blood cells), decreased potassium, elevation of phosphorus, urinary infections and hypertension.

Why is diet important in kidney failure?

Diet is important in patients with chronic renal failure, with three prominent factors:

Water intake
Cats with renal failure can become dehydrated more easily (because the kidneys have less capacity to conserve water by concentrating the urine). Maintaining an adequate water intake is very important, and, because cats get most of their water through food, in these patients their diet should include, whenever possible, canned wet food (or in bags) instead of dry food (I think).

Protein content
An ideal diet for a cat with renal failure should contain a low concentration of protein (most toxins accumulate in the blood in renal failure as a result of protein breakdown), and low-protein foods help decrease toxins Anyway, the reduction of protein in the diet has to be done with caution. A very low protein intake can cause weight loss that will be detrimental to the general state of health. For this reason, it is preferable to use specific commercial diets than "homemade diets."

Low protein diets tend to be less appetizing for cats. Cats with chronic renal failure who do not get used to these diets, it is preferable that they follow a normal diet to stop eating. Sometimes you can get them to eat a low-protein diet by offering them different varieties, heating the food and mixing a diet of this type with their normal diet for a period of time.

Low phosphorus content
A diet low in phosphorus in cats with renal insufficiency seems to be very beneficial to protect the kidneys from further damage. Commercial diets prepared for renal failure have a low concentration of protein and phosphorus. If a cat does not feed on these low phosphorus (low protein) diets, or if the blood phosphorus concentration is high, despite this diet, "phosphorus chelators" may be added to the diet (for example: aluminum hydroxide or calcium acetate) to reduce the amount of phosphorus that is absorbed. This should only be done advised by a veterinarian.

Other improvements in diets
Commercial diets for cats with kidney failure have other modifications, such as the addition of more fiber and some polyunsaturated fatty acids, which offer additional benefits in the treatment of kidney failure.

What other treatments exist for kidney failure?
An adequate intake of water together with an appropriate diet (see above), is very important in cats with renal insufficiency. These cats have a tendency to become dehydrated, which significantly impairs the functioning of the kidneys. It is essential that they always have water and their consumption should be stimulated by offering them water in different drinking fountains, using pet water sources or even enriching the water with flavors (chicken or tuna, for example), etc. Some cats with advanced renal failure benefit from periodic serum administrations, either intravenous or subcutaneous. These procedures are normally performed by the veterinarian, although in some circumstances it may be possible to administer subcutaneous serum at home.
Other treatments are used in possible complications that may arise as a result of renal failure, for example:

Potassium supplementation
Some cats with kidney failure have low blood potassium levels and this, alone, can make kidney failure worse. When this occurs they are given potassium supplements (tablets, pasta or powders that can be added to the diet).

High blood pressure
Cats with chronic renal failure may develop hypertension and being exposed to other secondary problems (bleeding in the eyes and retinal detachment that causes blindness, cerebral hemorrhage that causes nervous symptoms) in addition to the fact that this high blood pressure can cause further damage to the kidneys. This is why it is important to treat hypertension when it is diagnosed, since the treatment is direct and effective (with tablets).

Anemia treatment
In advanced renal failure the development of anemia is quite common. If it is mild it is not usually a problem, but if it is severe it can make the symptoms of lethargy and weakness worse. Depending on the causes of the anemia and its severity, there may be different treatment options including the use of anabolic steroids, iron supplementation, treatment of gastrointestinal ulcers and, in very advanced cases, supplementation with erythropoietin (the hormone that stimulates the production of Red blood cells).

Treatment of nausea and vomiting
Nausea and vomiting are very common in advanced renal failure and can seriously affect the quality of life and decrease the cat's appetite. There are different drugs to control these symptoms.

Use of "ACE inhibitors"
ACE inhibitors, such as benazepril, are a type of drugs that act primarily as vasodilators (dilate blood vessels). They are normally used in people with kidney failure to help in treatment for their benefits in renal function and reduce the loss of protein by the kidneys (which can be very high and harmful in kidney failure).

It is thought that these drugs may be beneficial in the treatment of cats with renal insufficiency although there is no clear certainty that all cats can benefit from them, nor from which cats are the ones that would benefit most. According to studies, cats with high loss of protein in the urine will have greater benefits. In all cats taking these drugs, the values ​​of blood and urinary tests can be monitored together with clinical symptoms in order to determine what benefits are being obtained.

What is the forecast?
When the damage to the kidneys is so severe that they have chronic renal failure, compensation and adaptation mechanisms are produced to try to maintain the normal functioning of the kidneys, although at some point these mechanisms will fail to produce a progression in renal failure. The disease is therefore progressive over time and may end up in need of euthanasia. However, the rate of progression of kidney disease varies considerably in each individual and proper treatment and care can improve the quality of life of affected cats and, at the same time, slow the progression of the disease.

What is kidney failure and what causes it?

In the urinary system we find the kidneys, the organs that are responsible for filter and eliminate harmful substances of the body of our feline for the production of urine. By filtering the blood, the kidneys have a series of tasks that are vital for all species:

  • Maintain a balance between water and minerals.
  • Eliminate chemical compounds introduced into the body and substances derived from the protein mechanism such as urea or creatinine.
  • The formation of red blood cells is regulated by a hormone that is made in the kidney, erythropoietin.

These substances that must be eliminated become part of the urine to leave the body of our animals. There are other more complex mechanisms but, for practical purposes, this is the correct renal function.

Therenal failure (IR) It is a slow but progressive alteration of these vital functions, being a disease that can be controlled but not cured. Among the best known causes that cause its appearance we have:

  • Kidney damage from toxins or mismanaged medications.
  • Polycystic kidney disease (common in Persian cats) that is inherited.
  • Tumors
  • Elderly cats, over 15 years old.
  • Bacterial infections.

There are many causes that can cause kidney failure in our cat, but once it has been triggered, we must be attentive to its control and treatment.

Main symptoms of renal failure in cats

Initially, the symptoms of renal failure may go unnoticed and may even be confused with other diseases. Before any of these symptoms we recommend you go to the veterinarian:

Differential diagnosis

The clinical signs are not consistent evidence for diagnosis They are assessments of the owner and / or veterinarian but must always be accompanied by laboratory tests. Annual visits from 8 years of age can help an early diagnosis of renal failure. Within the chosen routine tests we can propose:

  • Whole blood test (we look for an increase in creatinine and urea).
  • Urine analysis (physical, chemical, sediment and sometimes antibiogram).
  • X-rays and ultrasound They are not strictly necessary like the previous ones, but they are usually requested to observe the state of the affected organs.

Treatment of renal failure in cats

The treatment and care of the cat suffering from kidney failure will be essential since it is a progressive disease. As much as we treat the symptoms we observe we must have proper management and care to avoid relapses.

To start it is essential to talk about the medication since we will find many options. The veterinarian will decide, according to the chart, which will be the most appropriate for our feline. The use of antibiotics, vitamin complexes, minerals and appetite stimulants will dependof the patient, of the needs and symptoms that it shows.

The feeding It is another fundamental aspect and is one of the pillars to overcome this pathology. It is very advisable to choose one of the best feeds for cats with renal insufficiency that we find in the market, mainly those of high quality, but we can also follow homemade recipes for renal failure of the cat. This choice will depend exclusively on us and on the diet that until now our cat was following.

Finally we will talk about homeopathy, bach flowers and phytotherapy. In case of wanting to offer this type of products we need to turn to the most suitable professional and not self-medicate. These are medications, so if we choose natural therapies we will look for the veterinarian to do it.

This article is purely informative, at we have no power to prescribe veterinary treatments or make any kind of diagnosis. We invite you to take your pet to the veterinarian in case he presents any type of condition or discomfort.

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