Kidney disease and kidney failure

Kidney disease, deterioration and failure of the kidneys is a common problem in old age in dogs and cats, however an alarming percentage of young and middle-aged animals are succumbing to kidney failure too. The kidneys are fragile organs and take time to heal and in the case of progressive kidney disease, time is of the essence. Preventative measures in terms of a healthy lifestyle, which includes proper nutrition and exercise, are the best approach to prevent this condition in your pet. Kidney failure is the second leading cause of death in cats (after feline leukemia), according to Dr. Pitcairn (2005, p. 362). In order to understand this condition and how to prevent it, this article explains the function of the kidneys, causes, types and symptoms of kidney disease and conventional vs. holistic treatment and diet for pets diagnosed with kidney disease. If you suspect your pet has kidney disease it is imperative that you get a veterinarian diagnosis urgently.

The Function of the Kidneys

The body needs to consume food to receive vital nutrients that are necessary to maintain vital body functions. Once the nutrients have been extracted from the food and metabolised waste products are left over which must be removed from the blood stream, a process known as excretion.

The body has two bean shaped organs called kidneys that reside against the back muscles in the upper abdominal cavity and are responsible for extracting waste from the bloodstream supplied to them. In addition to excretion, the kidneys perform multiple functions vital to the health and normal functioning of the body.

The function of the kidneys include:​

  1. Filtering the blood and removing waste products, toxins and extra water from the blood. Waste products come from normal breakdown of active muscle, the food an animal eats and are also produced through metabolism. The waste products and extra water become urine that is excreted by the kidneys into the bladder via tubes called ureters. A healthy kidney can excrete a large amount of waste products in a small amount of urine. Some of the waste products excreted are:

  2. Urea: the metabolism of protein produces amino acids, which are deaminated to produce ammonia that is then converted to urea via liver enzymes. Urea, a compound containing nitrogen is commonly known as blood urea nitrogen (BUN). Urea is passed into the blood from the liver for excretion by the kidneys.

  3. Creatinine: another waste product in the blood created by the normal breakdown of muscle during activity.

  4. Regulating a number of chemicals and other properties in the blood. These can be summarised as:

  5. Regulating the bloods acid/alkaline balance and its electrolyte levels

  6. Regulating and releasing chemicals back into the blood like sodium, phosphorous and potassium. The right balance of these chemicals is important in maintaining the health of the body as excess or low levels can be harmful

  7. Regulating red blood cell count. When the kidneys are not receiving sufficient oxygen they produce a hormone which stimulates the bone marrow to produce more oxygen-carrying red blood cells

  8. Regulating the salt in the body and determining the correct concentration of salt that should remain in the blood. Excess salt is removed from blood by the kidneys and passed into the urine. The body requires a certain concentration of salt and water in the blood necessary for good health. By regulating the salt and water in the blood the kidneys ensure the correct concentration is maintained at the correct level.

  9. Regulating and balancing the water levels in the blood as they kidneys react to changes in the body’s water level throughout the day. When water intake decreases, the kidneys adjust accordingly and leave water in the blood instead of helping to excrete it.

  10. The kidneys work in conjunction with the liver in the activation of vitamin D, which promotes calcium absorption by the small intestine and makes it available for bone development that helps maintain calcium for bones that is vital for strong bones, muscles and overall health.

  11. The kidneys require constant pressure to filter the blood and also control blood pressure in order to keep it regular. When blood pressure drops too low the kidneys increase the pressure by producing a blood vessel-constricting protein that signals the body to retain sodium and water that restores normal blood pressure, (, n.d.).

Kidney failure and disease – its causes, types and symptoms

Kidney disease occurs when the kidneys are no longer able to perform their functions effectively and able to remove waste, which may ultimately lead to kidney failure. Mindell (2007, p. 87) states “A dog is considered to have kidney failure when 65-75 percent of both kidneys are not functioning”. Kidney disease is rarely diagnosed in pets because initially pets show no physical signs and the loss of kidney function is not usually evident until the pet experiences kidney failure (Mindell, 2007). Kidney disease is a devastating and aggressive disease as pets with kidney disease are unable to concentrate their urine, resulting in a large volume of urine which increases thirst and dehydration. One of the first signs of kidney problems according to Lazarus (1999, p. 228) is that “the pet drinks increasingly more water and excretes increasingly more pale or colourless urine”. Death from kidney disease occurs when only 15-20 percent of the kidney tissue is still functional, (Pitcairn, p. 362, 2005)

A number of contributing factors and causes may lead to kidney damage, these include:

  1. Diabetes and high blood pressure can cause kidney disease. Diabetes is a disease that keeps the body from using sugar effectively. When sugar is not broken down but stays in the blood, it can act like a poison and damage the kidneys. High blood pressure is more common to people than animals but can damage the small blood vessels in the kidneys. The damaged vessels cannot filter poisons from the blood as they are supposed to.

  2. A direct and forceful blow to the kidneys can lead to kidney disease.

  3. Ingested toxins, pollutants, poisons or the chemicals used for food production, lawn care, plastics, inhaled air, vaccines etc. can lead to kidney disease and many other serious and life threatening illnesses.

  4. A severe illness, such as cancer

  5. An imbalance of electrolytes

  6. Some over-the-counter medicines can be poisonous to the kidneys, for aspirin and ibuprofen are not recommended for pets and can cause significant damage to the kidneys.

  7. Bacteria that enters the urethra, ascends into the bladder and make their way up to the kidney cause an infection. If the infection is left untreated, it can cause permanent kidney damage.

  8. All infections, including gums, skin and teeth

  9. Lifelong exposure to processed, nutritionally void food, foods high in protein and phosphorous or an unbalanced ratio of calcium to phosphorous. Low quality, highly processed pet foods, in particular dry kibble that lacks the moisture content and high quality protein pets need. Commercial pet foods are being linked to many of the degenerative diseases seen in pets today.

  10. Lifelong dosing with monthly spot on treatments and chemical worming solutions which have to be filtered out by the kidneys

  11. Obesity

When the kidneys become damaged or impaired they:

  1. Are unable to remove waste, urea and other chemicals from the bloodstream which builds up in the blood, this is called uremia. According to Lazarus (1999, p. 228), “Uremia is poisoning of the entire body caused by accumulation in the bloodstream of waste products that are normally helped out of the body by healthy kidneys”. An increase of BUN in the blood can be the result of a diet that is high in protein content or decreased renal excretion.

  2. Fail to separate the protein from the wastes. Healthy kidneys take wastes out of the blood but leave in protein. Proteinuria means protein is found in the urine, and it is a sign of poor kidney function.

  3. Cause creatinine to build up in the blood. Healthy kidneys take creatinine out of the blood and excrete it in the urine to leave the body. Creatinine values are variable and can be affected by diet, so regular blood tests will determine if the kidneys are functioning properly and removing creatinine from the blood. Compared to BUN, creatinine is less affected by diet and more suitable as an indicator of renal function.

A veterinarian must diagnose kidney disease, the stage of kidney disease or degree or uremia is determined by measuring blood urea nitrogen (BUN), creatinine and electrolytes. Kidney disease is classified as either Acute Renal Failure (ARF) or Chronic Renal Failure (CRF).

ARF is a rapid deterioration of renal function that comes on suddenly over a period of hours to days, the symptoms are often severe and life threatening and immediate veterinary attention is required. If veterinarian treatment is immediately sought then there is a chance that the animal may survive acute kidney failure, however this depends on how badly the kidneys have been damaged.

ARF is usually caused by either:

  1. Ingestion of a poison, like antifreeze or a medication meant for humans like ibruprofen, or the Easter Lily plant

  2. A urinary blockage

  3. An overwhelming bacterial infection

  4. An imbalance of electrolytes

  5. Dehydration, caused by a lack of access to drinking water for long periods of time or in hot climates

  6. Decreased blood flow to the kidneys – which may occur during a surgical procedure, or as a result of heat stroke, or where there is heart disease

Signs and symptoms of ARF include:

  • Vomiting

  • Complete loss of appetite

  • Marked lethargy

  • Straining to urinate and decreased urine production

  • Disorientation

  • Physical weakness; loss of coordination

Urine output is a very important indicator for recovery from acute renal failure. Continued low or no urine output provides a poor indication of recovery and a sad prognosis for the animal.

Chronic Renal Failure is more common in older pets, is a slower process than ARF and develops over months or even years. Due to the kidneys ability to make highly concentrated urine with a large amount of toxins excreted in a small amount of water animals only need about 25 percent healthy kidney tissue to be free of clinical signs. As a result, symptoms of kidney damage are unfortunately only apparent when significant irreversible kidney damage has occurred. Animals with failing kidneys need more and more water to excrete the same amount of waste and toxins.

A pet in kidney failure will drink increasing quantities of water, until eventually it can’t drink enough water and toxin levels in the bloodstream increase.

CRF may also be caused by something other than damaged kidneys, for example a disease that decreases blood flow to the kidneys or a urinary tract blockage. In this case it is possible the kidney problem can be cured with appropriate treatment of the underlying cause.

Signs and symptoms of CRF include:

  • Animals drinking more water more frequently in an effort to eliminate waste and either passing large volumes of water or even urinating less.

  • Vomiting and diarrhoea due to the buildup of waste in the blood.

  • Blood in the urine.

  • Loss of weight.

  • Lack of appetite.

  • Low energy.

  • Pale gums due to decreased red blood cell production which leads to anaemia.

  • Weakness causes dogs to stumble, and their breath might have a chemical odor.

  • An unpleasant odour from the skin as it works to help eliminate waste and toxins from the body.

  • Hunched posture; reluctance to move.

  • Poor coat condition.

  • Mouth ulcers and bad breath from a buildup of toxins in the bloodstream.

  • High blood pressure, which can result in changes in the retina of the eyes.

  • Smaller than normal, enlarged and/or or painful kidneys.

  • Fluid retention in the limbs and abdomen.

  • Weakened bones and fractures from a lack of calcium and vitamin D.

  • Itchy skin caused by calcium and phosphorous deposits in the skin.

  • Stomach bleeds or bruised skin due to blood problems, and high blood pressure can cause sudden blindness.

  • Dogs also can develop a brownish tongue.

In many cases where CRF is the result of irreversible kidney tissue damage, renal function will stabilise for weeks or even months at a time. Although the disease will progress and kidney function will continue to deteriorate, the pet’s symptoms can be minimised with supportive treatment like herbal therapy and careful nutrition.

Kidney Failure Prevention

Prevention is better than cure and to ensure the health and longevity of an animal’s kidneys there are a number of preventative measures that pet owners can take. These include:

  • Feeding a species appropriate diet that is balanced over time. A proper diet that is free from toxins ensures that an animal receives the correct proportion and balance of nutrients required for health and proper functioning of all organs, including the kidneys. This diets need to include raw meaty bones, vegetables, fruit and offal.

  • Limiting vaccines and drugs. Titre testing determines an animal’s antibody count and whether or not an animal has sufficient levels against a previously vaccinated disease. In the case of low levels, only then are vaccinations required. Titre testing prevents exposing an animal to unnecessary toxins (in the form of vaccines) that the kidneys and liver must process. The less stress on a pet’s kidneys, the longer they’ll do their job effectively.

  • Not using plastic water or feeding bowls as the chemicals in these products leech into water and food and need to be removed from the bloodstream to prevent a buildup of toxins in the body.

  • Providing pure filtered drinking water. Tap water is full of chemicals which act as poisons. The kidneys have to work harder to filter these chemicals from their blood. Distilled water aids in flushing toxins from the system.

  • Observing an animals behaviour and noticing small changes from sleeping more, being irritable, drinking more water to loss of appetite. A change in behaviour is often the first indicator that something is medically wrong with an animal.

  • Keeping animals away from toxic and poisonous substances such as antifreeze, heavy metals, rat poison and other pesticides, common household medicines, and certain foods and plants.

  • Seeking immediate veterinarian treatment for urinary blockages or other illnesses that could lead to compromised kidney function

  • Insuring your dog is never struck, kicked or gets out in a roadway will prevent possible trauma to the kidneys that could lead to renal failure.

Conventional Treatment and Diet for CRF

Conventional veterinarians consider kidney disease in animals irreversible and fatal and recommended treatment focuses on fluid therapy to maintain hydration, treating symptoms and managing the disease with drugs and a prescription low protein, low phosphorous kibble diet to prevent further damage to the kidneys. Conventional vets believe that protein levels should be reduced for a pet diagnosed with kidney disease because protein is poorly metabolised by pets with kidney disease and it creates a high nitrogen load that can further stress the liver and kidneys

This is not correct for most animals as protein reduction has little impact upon the progression of the disease. In reality, reducing the protein level may actually reduce the effectiveness of the kidneys as the filtering process is tied to protein in the diet. Reducing protein reduces the kidneys ability to filter and remove toxins from the blood.

Although a low protein kibble diet and regular fluid therapy can prolong the life of the animal it doesn’t do anything to repair the damaged kidneys or restore health. As a last resort, an organ transplant is another course of treatment but it is extremely expensive and not always in the best interest of the animal.

Holistic Treatment and Diet for CRF

One of the most important things to do for a pet diagnosed with kidney disease is to move it from a kibble diet and onto fresh foods because most commercial pet foods are laden with preservatives, artificial colours and additives, very low in water and made of poor quality, hard to digest protein all of which need to be excreted by already stressed kidneys. Dodds and Laverdure (2015, p. 175) state “a dog’s body must use a significant amount of water just to move kibble through his GI tract during digestion. Dry foods are also usually high in carbohydrates, which can cause inflammation in the kidneys”, and advise against the use of kibble diets because “they can actually aggravate the problem by contributing to dehydration while simultaneously adding too many carbohydrates (2015, p. 175).

Pitcairn (2005, p. 363) states “It is important to avoid feeding special acid-forming diets to cats with kidney disease. These are the commercial foods formulated to prevent cystitis and are advertised as such. Chemicals have been added to these diets to force the urine to be acid; one side effect is that the body becomes too acid, and kidney function is reduced”.

A fresh food diet with a high moisture content (generally four times higher than kibble) and high quality easily digested protein is a more desirable choice as it is full of healthy nutrients that do not put stress on the kidneys and help to prevent dehydration.

High quality, easy to digest sources of protein recommended for a pet with kidney disease includes raw eggs and raw meat (poultry is more digestible than red meats), as cooking changes the structure of protein it make it hard to digest.

It is also imperative to prevent dehydration in a pet with CRF due to the large amount of water that is lost from urination. Also due to water loss is the loss of potassium that needs to be supplemented in the animal’s diet to prevent muscle weakness and heart rhythm disturbances.

Herbal Treatment for Kidney Disease

Natural treatment for kidney disease focuses on giving the kidneys the support they need to self-heal in the form of herbs and a species appropriate nutritional diet. Herbal treatment, unlike conventional treatment, focuses on the natural healing of the whole body and not just the symptoms or management of kidney disease. Tilford & Wulff (2009, p. 17) state the therapeutic effort of herbs is to “support the body in its efforts to correct the problem itself”. It is important to consult a holistic vet, an animal naturopath or qualified animal herbalist before giving herbs to your pet as some herbs are not recommended for pets with kidney disease and may actually damage the kidneys further.

Herbs support kidney function, boost the immune system and cleanse impurities from the blood. In contract, prescription medication introduces chemicals into the body that the kidneys have to filter and remove, putting additional strain on them and compromising the healing process.

When the kidneys are not working properly this puts strain on the other organs that filter and excrete toxins, for example the liver and the skin, which may lead to them becoming compromised too. A holistic approach to healing with herbs involves supporting the functions of the skin and liver in addition to healing the kidneys.

Herbs can be used to tackle kidney failure in three ways:

  • Improve blood circulation in the kidneys;

  • Reduce inflammation of the kidneys and the urinary tract; and

  • Increase urine output.

The following herbs are explicitly recommended to assist the body when the kidneys are compromised, all herbs should be organic and not sprayed with any chemicals:

  • Parsley: organically grown leaves combined with dandelion leaves help to flush toxins from the kidneys daily

  • Gingko: dilates and improves the tonicity the blood vessels in the kidney but also has anti-inflammatory properties which reduce inflammation in the urinary tract

  • Hawthorn: increases blood circulation in the kidney

  • Dandelion, alfalfa and nettle are diuretic herbs which gently increase urine output. Dandelion is a good source of potassium that helps rebuild the kidney and aid detoxification

  • Echinacea: as an anti-bacterial is useful for treating a urinary tract infection or early stages of kidney failure

  • Marshmallow, couchgrass and corn silk: reduce inflammation

  • Urva urs (bearberry):

  • Astragalus: strengthens kidney circulation

  • Goldenrod: a kidney tonic

Avoid herbs that contain large amounts of aromatic volatile oils and those with considerable amounts of tannins, especially if the kidneys are inflamed (Tilford & Wulff, 2009).


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