Kidney disease in cats is a condition that affects the healthy functioning of the kidneys. Your cat’s kidneys perform many vital functions.
They filter about 20 percent of the body’s blood and regulate the water in the body and electrolyte balance. They also help to regulate pressure in the arteries and acid-base balance.
The kidneys regulate the excretion of calcium and the production of the active form of vitamin D. They play an essential role in the metabolism of some vital minerals required by the body and produce a substance called erythropoietin which stimulates the production of the red blood cells in the bone marrow.
Furthermore, the kidneys are responsible for removing waste products and chemicals of metabolism via excretion in the urine. Impaired functioning of the kidneys may have severe consequences on the cat, as with most mammals.
The most obvious sign that an animal may be experiencing kidney dysfunction is urination and increased thirst. Gastrointestinal symptoms such as vomiting, bad breath, poor appetite, and diarrhea may appear in later stages of the disease.
A gradual decline in body condition accompanied by weight loss and poor hair coat may also occur. Some animals with kidney disease may show no observable symptoms; the disease is discovered during a routine physical examination and screening tests of urine and blood.
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Types of Kidney Disease in Cats
There are two types of kidney disease in cats. These are:
Acute renal disease
This type of renal failure occurs suddenly over a couple of days or weeks. Acute renal failure can happen in cats of all ages and usually occurs as a result of the following:
- Poisons from toxic plants like lilies, antifreeze, cleaning fluids, and certain human medications are very poisonous to your cat’s kidneys. Poisons are usually the most common cause of acute renal failure.
- Shock due to rapid loss of blood or dehydration. Overheating in hot weather, vomiting, significant rise in activity, and diarrhea can cause a massive reduction in body fluids.
- Trauma to the bladder or pelvis.
- Heart failure accompanied by low blood pressure, which reduces the flow of blood to the kidneys.
- Blockages that diverts the flow of blood into the kidneys and the flow of urine out of it.
Acute renal failure can be reversed if diagnosed early enough.
Chronic renal disease
Chronic renal disease is most common in older cats. Cases of chronic kidney disease are progressive over time which leads to a gradual decline and worsening of the condition.
The rate of deterioration varies from one cat to another. The damage to the kidneys is often irreversible and impairs their ability to function and remove waste products from the blood. The exact cause of chronic kidney disease is often unknown.
However, some of the known causes of chronic kidney disease in cats include:
- Kidney tumors such as lymphoma, a solid tumor of white blood cells
- Polycystic kidney disease (PKD), an inherited diseases that is chiefly observed in Persian cats, where multiple fluid-filled cysts gradually replace normal kidney tissue
- Toxins and drugs
- Pyelonephritis, a bacterial infection that causes significant damage that can lead to chronic kidney disease in cats
- Glomerulonephritis – the inflammation of the glomeruli, which are individual units within the kidneys that filter blood
Other conditions that can cause chronic kidney disease include congenital disabilities, low blood potassium (hypokalemia), high blood calcium (hypercalcemia), and trauma. Some cases of chronic kidney disease in cats may be treatable if the underlying cause of the disease is identified.
However, treatment is aimed at managing the illness and complications that arise from it.
Signs and Symptoms
Symptoms of kidney disease in cats are often vague and could be attributed to other conditions. Some symptoms can occur as a result of toxins in the blood, while others may arise from complications due to the body trying to adapt to the condition.
The most common signs of kidney disease in cats are:
- Weight loss
- Increased thirst
- Increased urination
- Poor appetite
Other symptoms include:
- Hypertension (high blood pressure)
- Poor coat
- Bad breath (halitosis
- Weakness and fatigue
Veterinarians often use blood tests and urine analysis (urinalysis) to determine the concentration of waste products and chemicals that a healthy kidney would usually filter or regulate.
Urea and creatinine are the two substances that are commonly analyzed to determine the presence of kidney disease. Cats with a high concentration of the two substances in their blood indicate that their kidney may not be functioning properly.
However, other conditions such as dehydration may contribute to the increased concentration of these substances. The veterinarian will base their diagnosis on at least two blood samples obtained within weeks of one another.
Other blood components like electrolytes (potassium and sodium), red blood cells, phosphorus, and proteins are also crucial in evaluating the presence of kidney disease in cats.
In urine analysis, the vet doctor will consider the concentration of urine, its pH blood cells, bacteria, the presence of protein, and other cells that are not typically found in feline urine. These would prove critical in determining the health of a cat’s kidneys.
Other tests that can help evaluate a cat suspected to have kidney disease include imaging tests such as X-rays, abdominal ultrasounds, and in some rare cases, microscopic evaluation of biopsy samples.
Treatment of kidney disease in cats often depends on treating the underlying condition causing the disease. Many cats affected by kidney disease would benefit a lot from a change in diet alongside other treatments. The vet doctor would recommend the best treatment for your cat.
Treatment options include:
- Special diets: Foods with low protein and low phosphorus can help lower the level of waste products in the blood. These can be prepared at home or made readily available at your vet clinic.
- Antibiotics: Cats with kidney disease caused by bacterial infection would benefit significantly from taking antibiotics.
- Phosphate binders: Oral phosphate binders such as aluminium hydroxide can go a long way in reducing phosphorus levels in the blood and improving the cat’s well-being while slowing the progression of the disease in cases of chronic kidney disease.
- Vitamin B and C: These water-soluble vitamins are necessary for the cat’s well-being as they are lost due to failing kidneys unable to concentrate the urine. Cats affected by kidney disease would require daily supplementation.
- Potassium supplements: Cats with kidney disease tend to lose a lot of potassium in the urine, which results in muscle weakness, stiffness, and poor hair quality. Low levels of potassium may also contribute to the worsening of kidney failure.
- Blood-pressure lowering drugs: High blood pressure is a common symptom in cats with kidney failure, which can exacerbate kidney damage. Drugs that lower their blood pressure may be required in some cases.
- Anti-emetics: For cats who experience vomiting, the use of anti-vomiting medication (anti-emetics) can help reduce nausea and improve appetite.