Feline Chronic Renal Disease (CKD)

A cat’s urinary system consists of the two kidneys, bladder, the ureters (small tubes) that connect them, and the urethra that empties the urine from the bladder. There are two serious conditions that commonly affect the urinary system of cats.  Renal disease affects the two kidneys and is also called chronic kidney disease (CKD). Another completely different condition that affects the urinary tract in cats is feline lower urinary tract disease (known as FLUTD) which involves a cat’s bladder & urethra.

The two kidneys have many vital functions including the removal of the body's waste products, and plays an important role in maintaining the body’s hydration and electrolyte/salt levels. The filter-like working parts of a kidney are called nephrons, each of which consists of a blood filter attached to a complex piece of pipe work called a tubule. Both kidneys contain hundreds of thousands of nephrons. When a significant number of them become damaged or are destroyed by disease irreversible chronic kidney disease can develop.

Only 30% of the kidney's full functioning capacity is needed for normal functioning. Therefore, no symptoms or changes on blood tests will be seen until approximately 70% of kidney function is lost. It is important to begin treatment as soon as the first symptoms appear. As CKD s primarily a degenerative disease, it is most common in older cats (> 13 years of age). It has been estimated that around 16 per cent of cats over 15 years of age have significant kidney dysfunction.

Common Symptoms

May include any of the following:

• Weight loss 
• Increased drinking
• Increased urine production
• Pale, whitish coloured gums
• Reluctance to eat
• Depression/lethargy 
• Gingivitis/oral ulcers
• Vomiting
• Bad breath
• Poor coat/fur/skin condition

Renal failure may be termed acute or chronic. In acute renal failure, a significant number of nephrons all stop working suddenly at the same time, as may occur with lily poisoning or sudden lower urinary blockages. Chronic kidney disease (CKD) occurs more gradually due to progressive underlying diseases, and is the most common type of renal disease to affect cats.

Diagnosis and treatment

Kidney disease can be a life-threatening condition.  The long-term outlook for most cats with CKD is poor, but many can enjoy a good quality of life if treatment is initiated promptly, and is diligently carried out by yourself with assistance from your vet. Staging your cat's CKD can give us a better indication on their outlook and individualise their treatment.

We generally diagnose CKD by carrying out blood and urine tests; however we may also recommend blood pressure measurement, thyroid testing and further urine tests to look for infection and protein loss. This also allows us to stage the CKD. Imaging may also be required such as x-rays and/or ultrasounds.

Warning: If your cat has been diagnosed with CKD but suddenly shows new symptoms contact us immediately. Other conditions, which may seem trivial in a healthy cat could affect a CKD cat more seriously, and may require prompt treatment.  In most cases of CKD the cause is not identified, so your vet may only be able to begin treatment aimed at alleviating the symptoms:

• Intensive care/hospitalisation – If your cat is very ill, we will suggest admission to hospital to allow administration of intravenous fluids. This is required to correct dehydration and helps flush toxins out of the bloodstream.  We will also assess the need for additional investigations or medications for your cat.
• Dietary management - Specially designed Prescription Renal diets are highly recommended and studies prove that they can significantly increase life expectancy after diagnosis. Available diets include wet food (canned and pouches) and biscuits. Introduce gradually (over 1-3 weeks) to increase acceptance.
• Provide adequate fluid intake - At home, you must ensure your cat has permanent access to fresh water. It can be helpful to add water into the food to increase water intake. Alternatively, your vet may suggest home fluid therapy once to twice weekly. This involves injecting warmed sterile fluids under the skin with a sterile needle and syringe.  This should only be done with specific instruction by your vet – do not attempt without advice from your vet. (Equipment and fluids available through the clinic)
• Specific medications may be required for urine infections (antibiotics), urine protein loss ("proteinuria") or high blood pressure (hypertension). Some cats will develop electrolyte and mineral imbalances and thus regular monitoring is crucial.
• Concurrent disease – as CKD affects older cats we often have to manage concurrent chronic illnesses including hyperthyroidism, hypertension and arthritis.
   

Ongoing monitoring

Your vet can recommend the best course of action for ongoing monitoring for your cat – this will include regular check ups to include a physical examination and weight check, in addition to possibly repeating some blood and urine testing, and blood pressure measurements.

More information: www.iris-kidney.com