The Silent Killer
It is the leading cause of death of cats. It is one of the top causes of death of dogs. And yet many pet owners - dog owners in particular - are unaware of chronic renal failure. What is it? What are the symptoms and how is it diagnosed? Is there any treatment? Perhaps even more important, what can be done to reduce its effect and prolong a pet's life?
This is part one of a multipart entry on the subject of Chronic Renal Failure in dogs and cats.
What is CRF?
The primary function of the kidneys is to filter out of the blood waste products left behind from the body's metabolism. Excess water is also removed and the combination becomes urine. In addition to cleansing the blood, the kidneys help regulate blood pressure and blood composition (pH, red cells, sugar, volume, water). Renal failure comes in two primary forms: acute (ARF) and chronic (CRF). In both ARF and CRF, renal function is impaired. CRF can also be called chronic kidney disease (CKD).
Acute renal failure may occur quickly when a pet consumes something poisonous - antifreeze, raisins, lily plants (cats) - or from a severe bacterial infection. If caught quickly, ARF is usually treatable. If not, impairment can be significant, putting the pet's life at grave risk.
Chronic renal failure takes place over a protracted period of time (typically many months or years). While it can sometimes occur in young animals, CRF is most commonly seen in older dogs and cats. CRF generally does not have an attributable cause, has no cure and the resulting kidney impairment is not reversible.
What are the symptoms?
CRF is a silent killer primarily because the symptoms are not manifest until the kidneys have lost most of their function and are significantly impaired. This "silence" is in part because the kidneys are able to perform acceptably well even while they are losing their capacity to work. Some of the early symptoms may also be difficult for a pet owner to pick up upon as a decisive indication of medical troubles in their pet.
One of the first signs of problems is increased thirst. Unfortunately, the increase may not be noticeable to the owner until it becomes significant. In warmer climates it can also be difficult to separate abnormal water consumption from normal variability caused by temperature and humidity swings.
Another symptom that may show before others is an increase in the frequency and quantity of urination. Again, this may happen gradually over time so as not to stand out as a large departure from normal until considered against conditions many months, not days, prior.
Additional symptoms arise as the impairment becomes more significant and the kidneys can only function at a greatly reduced level. Most noticeable will be a loss in the pet's weight and decreased appetite. Lethargy may also be apparent. Unfortunately, by this point kidney function is usually greatly reduced and it may no longer be possible to take counter measures to slow the impairment process.
Other symptoms, often at the latest stages, are nausea, vomiting, blindness and seizures.
Part two will cover diagnosis and treament.