The function of the kidney
Kidneys have multiple functions. Their main job is to remove the waste products from the blood in the form of producing urine. They also help to maintain electrolyte and nutrient levels in the blood.
Chronic kidney disease
The kidneys have a large amount of spare capacity to perform their functions. Thus at least 70% of the kidney needs to be affected before clinical signs are seen. This means the damage has been slowly occurring over some time before diagnosis.
In the initial stages, the kidneys cope by excreting the waste products at a lower concentration but over a larger volume. However, once the disease progresses, the rate of removal reduces and causes a sudden elevation of waste products in the bloodstream and the sudden onset of severe disease.
What are the causes of CKD?
Numerous disease processes can lead to chronic kidney disease, including congenital malformations, infections, cancer and degeneration. Chronic kidney disease is the end stage of varying disease processes rather than a specific cause on its own.
How is the disease diagnosed?
Chronic kidney disease is usually diagnosed by identifying the two waste product levels, Urea (BUN) and creatinine (Crea), in the bloodstream. These markers are usually seen elevated when kidney dysfunction has become severe (70%) due to the kidney’s inability to cope leading to an increased level of waste products in the bloodstream.
Other blood values, such as phosphorus, potassium and red blood cell counts are also important to determine the extent of kidney dysfunction. A urine analysis will also allow us to check the concentration of urine, blood and protein presence which will all help us to identify the extent of dysfunction.
In recent years, there has been a new blood test marker, SDMA, that allows us to identify kidney disease in its early stages (~35%). This marker is useful to allow us to identify kidney dysfunction before it reaches a severe stage.
How does CKD affect my cat?
Because the kidneys perform a variety of different functions, the clinical signs of kidney disease can vary. The most common changes noted are weight loss, poor hair quality, in appetence, halitosis (bad breath), lethargy. Patients can also drink and urinate more but this is less commonly seen. Vomiting and diarrhoea are other clinical signs that can present.
Is it curable?
Unfortunately, once damaged, kidneys have a very limited ability to recover. Treatment is aimed to stabilize and manage the dysfunction to allow a slower progression of disease. As such, chronic kidney disease requires long term management, but if managed well, patients can retain a good quality of life.
What treatments are available?
Depending on the blood results and your pet, several different treatments may be required to treat the different problems that arise. The extent of treatment will vary depending on the presentation of your pet and the severity of disease. Our veterinarians will assess your pet and explain to you each step accordingly. The following is a list of treatments that may be required in a kidney disease patient.
- Fluid Therapy
As most kidney disease patients are dehydrated and unable to maintain their hydration as well. Fluid therapy is usually crucial in initial phases to stabilize a patient. Depending on the severity of disease, our vets may recommend an initial hospitalization period to allow intravenous fluid therapy (aka drip). Patients may also require to be maintained on fluid therapy subcutaneous injections at home, depending on their situation. - Diet changes
Low protein and phosphorus diets are very useful to reduce the level of waste products, thereby reducing the load on the kidneys. Special diets are available for such purposes, e.g. Royal Canin Renal & Hills k/d.. They come in both wet and dry forms. Gradual introduction is recommended and even warming the food initially to increase its palatability. - Phosphate Binders
Reducing blood phosphate can have a major effect in improving well-being and slowing disease progression. These medications are mixed with food and may be recommended depending on your pet’s test results. - Hypotensive & Anti-proteinuria drugs
Large number of patients have high blood pressure from kidney disease, as well as an increased loss of protein in the urine. Medication may be required to lower the blood pressure and reduce the protein loss from the urine as well. - Anaemia
The kidneys secrete a hormone that stimulates red blood cell production. Kidney disease patients may have a low red blood cell count (anaemia) due to the reduction of red blood cell production. An injection of this hormone can be given in cases that require it. - Antibiotics & Other Medications
Depending on your pet’s presentation and results, antibiotics may be required if a secondary infection is suspected. Other medications may be required depending on your cat’s symptoms and presentation.