Chronic Kidney (Renal) Failure
Chronic kidney (Renal) Failure,
Kidneys are vital organs that eliminate toxins from the body and regulate electrolytes and maintain blood pressure. Each kidney is composed of thousands of nephrons. Chronic renal failure (CRF) happens when the “nephrons” start dying, which leads to toxins and waste accumulation, electrolyte imbalance, blood pressure disturbances and anemia. CRF is the number one diagnosed clinical disease in older cats. It is usually a slowly progressing and irreversible disease.
What can cause a CRF to start?
Two groups of renal diseases that lead to CRF:
Congenital renal diseases:
– Polycystic Kidney Disease (PKD): Genetic (inherited) renal disease mostly seen in Persians and crossed Persian cats.
– Renal hypoplasia: Happens when the patient is born with not enough functioning nephrons.
Acquired Kidney diseases:
– Pyelonephritis: Bacterial infection of the kidneys that can occur following a urinary tract infection.
– Chronic interstitial nephritis: represents the most common cause of renal failure in older cats with the kidney tissue becoming a fibrotic tissue (scar tissue). Researches are still going on to try and determine specific causes for this condition.
– Glomerulonephritis: it is an auto-immune disease (dysregulation of the immune system) that leads to an inflammatory damage of the kidneys
– Kidney tumors such as lymphomas
– Amyloidosis: happens when amyloid (= protein) over-accumulates in the kidneys. Amyloidosis is seen in Abyssinian cats.
– The dental connection: Just like for human beings, cleaning the teeth, removing the tartar can contribute to better health in general and can lower the risk of kidney failure. The bacteria present in the mouth from dental problems certainly contribute to kidney failure (and heart valve disease) when entering the blood circulation through the gum.
– Elevated blood pressure.
– Hyperthyroidism. Cats are prone to suffer hyperthyroidism
What are the symptoms of CRF?
If CRF is diagnosed with blood tests and often imaging of the kidneys (x-rays, ultrasound) many symptoms can suggest renal failure:
– Excessive drinking and urination referred to as polyuria/polydipsia
– Loss of appetite
– Weight loss
– Poor hair coat
– Putrid breath with mouth ulcers
– Cracking sound in jaw
– Diarrhea or constipation
– Convulsion, hypothermia, coma.
How to diagnose a CRF?
Your veterinarian will perform several tests to make the diagnosis:
– A urine test will show that the cat’s urine is dilute (kidney unable to eliminate toxins in the urine)
– A blood test will measure raised levels of Urea, Creatinine, and Phosphorus. The most accurate parameter, creatinine will enable your veterinarian to grade the severity of the CRF.
– Abdominal ultrasonography (scan) might be necessary to visualize the kidneys and precise the diagnosis.
In some cases when a cause such as a kidney infection has been identified, treatment for the cause is possible.
But most of the time treatment is rather a management of the kidney failure rather than cure. IV fluid therapy is often required at the beginning of the treatment to correct dehydration and continuation of the treatment are aimed at supporting renal function. With sufficient water intake, adjustment of the diet and the protein content to limit the amount of waste, potassium, and vitamin-D, supplementation, management of high blood pressure, treatment of the anemia, treatment of the vomiting and use of ACE inhibitors.
There are four different grades of chronic renal failure. Therefore, the prognosis depends on the current grade of the cat. CRF being a slowly progressive disease and if diagnosed and managed early enough, cats can live for months to years with a relatively good quality of life.
Dr. Mehdi Mzabi, Veterinarian