Chronic Renal Failure (CRF) is a serious condition evidenced by gradual, irreversible deterioration of kidney function over a period of months or years.

Weight loss, excessive thirst and urination, loss of appetite, vomiting, difficulty in urinating , dull coat

Older cats become especially prone to CRF. Approximately one in ten cats aged ten years has CRF. That figure rises to 30% for cats aged fifteen years. Cats mask their symptoms well, so usually more than half of kidney function has already been lost before symptoms become apparent. So, be especially observant.

Hyperthyroidism is the medical term to describe the signs and symptoms associated with an over production of thyroid hormone. Hyperthyroidism is a condition caused by the effects of too much thyroid hormone on tissues of the body.

Chronic vs. Acute Renal Failure

Renal failure may be either chronic or acute. Chronic Renal Failure (CRF) is a progressive, irreversible deterioration of kidney function. Because cats hide their illnesses and the very early signs of CRF are subtle, this disease may only be recognized when the patient reaches the 70% deterioration level and more dramatic symptoms are observable. The seemingly sudden onset may appear to be an acute condition but is most often a crisis point of CRF. By comparison, Acute Renal Failure (ARF) is characterized by an abrupt shutdown of kidney function, most often accompanied by oliguria (reduced urine production). The primary causes of ARF in cats are: urinary obstructions, infectious diseases, trauma, and the ingestion of toxins - the most common one being ethylene glycol which is contained in antifreeze. ARF is extremely serious and can quickly become fatal. Immediate veterinary treatment is imperative. Though the prognosis is usually poor, if damage has not been too severe and medical treatment is aggressive, it may be possible for normal kidney function to be restored.

 

Age-related Deterioration

CRF is one of the leading causes of illness and death in older cats. If the cat is age seven or older, it's a good idea to check for CRF during each annual exam, with a blood test, urinalysis and blood pressure measurement. With early detection, proper diet, and hydration, cats may remain happy and active for quite some time before the inevitable decline.

 

Relationship to Hyperthyroidism

Hyperthyroidism is one of the most common diseases of cats, particularly middle-aged and senior cats. Hyperthyroidism increases the blood flow to the kidneys and may mask symptoms of CRF. Recent studies indicate that a significant percentage of cats who were treated for hyperthyroidism (whether the treatment was surgical, radiological, or  life-long medication) showed symptoms of CRF. These treatments reduce the thyroid hormone in the cat's system. Among other things, this reduces the blood flow to the kidneys. CRF that had previously been masked becomes apparent. Sub-clinical kidney failure can become clinical and even healthy kidneys can undergo some deterioration.

 

It is crucial to monitor kidney function on a regular basis in cats who are being treated, or who have been treated for hyperthyroidism.

 

Perspectives on treatment options

CRF is a terminal illness. There are several methods which have proven successful in providing months or even years of comfortable life after diagnosis. This is not an exhaustive list, but provide some ideas of therapies which have offered hope.

 

Subcutaneous fluids (also known as sub-Q's or Lactated Ringer's solution) are fluids that are administered through a needle which is inserted under the skin. The Supreme Wirdle has had this form of treatment. No treatment is perfect for all patients. While this extended the lives of countless CRF cats, cats with heart conditions can be put in extreme danger through the administration of fluids. Also, excessive fluids can put pressure on the pleural cavity and temporarily collapse a lung.

 

The veterinarian may prescribe a low protein/low salt/low phosphorus diet for the cat. This diet is designed to reduce the amount of waste materials in the system that must be filtered out by the kidneys. The low salt and low phosphorous help control the electrolyte imbalances that are common with CRF. This diet may slow the progression of the disease. Some experts believe that any benefit from eating low protein food may be from the lower content of phosphorous contained in the food rather than the low protein itself. Furthermore, some believe that a low protein diet contributes to weakness and muscle wasting, two very common symptoms in CRF cats.

 

 

 

 

For further reading… a list of resources used in the compilation of this article.

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