Introduction
Chronic renal failure (CRF is caused by long-term insult to the kidneys. CRF can be present without overt clinical signs; this stage of the disease is called renal insufficiency, rather than renal failure. Unfortunately, once sustained clinical signs appear, the kidneys have lost most of their ability to filter waste products from circulating blood, excrete the end-products of metabolism in the urine, regulate blood pressure, contribute to red blood cell production and regulate the concentrations of hydrogen, sodium, potassium, phosphate and other electrolytes in the cat’s system.
Symptoms of Feline Chronic Renal Failure
When the symptoms of CRF do become noticeable, they typically include one or more of the following:
- Marked increase in thirst and water intake (polydypsia)
- Marked increase in urine output (polyuria)
- Urination in inappropriate places (outside the litter box)
- Urination at inappropriate times (during sleep)
- Decreased or even complete absence of urination (anuria)
- Hunched body stance (due to abdominal pain)
- Stiff gait
- Bloody urine (hematuria)
- Loss of appetite (inappetance; anorexia; likely due to nausea)
- Weight loss
- Vomiting
- Diarrhea
- Constipation
- Dehydration
- Lethargy
- Sluggishness
- Weakness
- Bad breath (halitosis; uremic breath odor – smells like ammonia)
- Oral ulceration
- Drooling/excess salivation (ptyalism)
- Brownish discoloration of the surface of the tongue
- Poor hair coat (dry; flaky)
- Decreased self-grooming activities
- Poor body condition
- Pale gums and other mucous membranes
- Bleeding/clotting problems
- Altered cognition (changes in mental state)
- Elevated blood pressure (hypertension)
- Blindness (sudden onset)
- Seizures
- Coma
- Death
Cats at Increased Risk
Chronic renal failure is more common in cats than in dogs. Certain breeds seem to be predisposed to developing CRF. These include the Maine Coon, Abyssinian, Persian, Siamese, Russian Blue and Burmese. Elderly cats usually develop some degree of renal failure, depending upon how long they live. Hyperthyroidism and chronic renal failure are often seen in the same aging cat, as both are considered to be geriatric feline diseases. Cats with prior episodes of acute renal failure have an increased risk of developing chronic renal failure.