Caused by age, genetics, environment and disease, chronic renal failure (CRF) results in the deterioration of the kidney function in cats, according to the Feline CRF Information Center. While chronic renal failure can be managed with diet and medication, it is a terminal condition. When the end stages of the disease emerge, it is important to consider euthanasia as the quality of life of the animal is greatly decreased, according to Tanya's Comprehensive Guide to Feline Chronic Renal Failure.
Kidneys produce a hormone called erythropoetin which causes bone marrow to make new red blood cells. Since renal failure reduces the functioning of the kidneys, erythropoetin production slows or stops, affecting the red blood cell production in cats, according to Net Pets. Signs of anaemia include lethargy, pale gums, depression, decreased activity, panting and increased heart rate. Mild anaemia is treated with blood transfusions or medications such as Epogen, a synthetic version of erythropoetin. Eventually cats develop antibodies to the medication, resulting in severe anaemia, in the end stages of CRF, according to Net Pets.
Weakness or Inability to Walk
End stage CRF causes low levels of potassium, high levels of phosphorus, metabolic acidosis, and anaemia, according to Tanya's Comprehensive Guide to Feline Chronic Renal Failure. In the final stages of the illness, these conditions fail to respond to treatment. Cats in the end stages of the disease experience extreme weakness leading to the refusal of food, incontinence, hiding or the appearance of dull, sunken eyes, according to Tanya's Comprehensive Guide to Feline Chronic Renal Failure.
Very High Urea and Creatinine Levels
In the end stages of CRF, when a veterinarian checks your cat's blood work, it will reflect an extremely high level of urea, also known as blood urea nitrogen (BUN) over 150, and a high level of creatinine, over 7.0, according to Tanya's Comprehensive Guide to Feline Chronic Renal Failure. Since the kidneys filter and secrete small amounts of BUN and creatinine regularly, elevated levels indicate a failure of the kidneys to function properly. These levels can result in inflammation of the brain or seizures. If, after trying subcutaneous fluids for a few days with your vet, your cat's symptoms do not improve, worsen, or result in fluid in the lungs (also called pulmonary oedema), your cat may be in the end stages of the disease.
Inability to Urinate
CRF causes increased thirst and urination in cats throughout the illness, due to dehydration. In the early stages of the disease, the kidneys cannot concentrate the urine, as a normal cat would, but still produce it. When the kidneys no longer can produce urine at all, they kidneys have failed, called anuria. Anuria usually results from acute renal failure (ARF), a sudden onset of the disease caused by toxins, or in the end stages of CRF, according to Pet Place. Though sometimes treated with diuretics, this stage usually indicates imminent death.
When dealing with the end stages of CRF, multiple symptoms will indicate a failure of the kidneys to function, including coma. In ARF, similar symptoms occur as an abrupt shutdown of the kidneys occurs, usually due to infection, urinary obstruction, ingestion of toxic chemicals (such as ethylene glycol) or trauma, according to the Feline CRF Information Center. ARF is reversible with proper treatment, but CRF ultimately results in death, though treatment can prolong the quality of life. Dialysis and kidney transplants can also treat CRF, according to the Feline CRF Information Center.