Chronic Renal Failure

« Back to Glossary Index

Chronic Renal Failure means “long-term” kidney failure and is more commonly seen in older dogs, although it can affect dogs of any age. Any sign of renal failure requires urgent veterinary attention.  Importantly, the kidney produces  erythropoeitin (EPO) which stimulates red blood cell production and chronic renal failure therefore cause anemia.The kidney performs many other functions, including controlling blood pressure, blood sugar, blood volume, electrolyte & water composition in the blood, pH levels & excretes (expels) toxins.

The healthy kidney “monitors” oxygenation levels in the blood stream & will produce more erythropoeitin if oxygen levels are low. The kidney also produces certain hormones & enzymes. The kidney  processes Vitamin D to maintain healthy calcium levels in the body.

Symptoms of renal failure gradually appear over a long time. It is better to look out for any early signs of renal failure, so that treatment can be started as soon as possible. There is no cure for chronic renal failure, nor can it be reversed, but it is possible to slow down further deterioration with the correct treatment.

Symptoms of renal failure include increased thirst, decreased or lack of urination, increased urination (amount & frequency), blood in the urine, lethargy, depression, weight loss/low appetite, mouth ulcers (due to toxin build-up), sudden blindness, vomiting, constipation or diarrhea, high blood pressure, pain around kidney region, water retention (oedema) in the abdomen and/or legs. Your vet can perform a blood test (including BUN & Creatinine) & urinalysis to test renal function. Dogs with chronic renal failure are often anemic due to low EPO, have high protein enzymes, high blood urea nitrogen (BUN), high creatinine & electrolyte levels out of normal ranges. Urine may contain protein or blood. The kidneys sometimes shrink (become smaller) or become enlarged due to renal failure, so scans/x-rays can be done to examine them for any abnormalities, including size & shape. A normally functioning kidney can produce diluted or concentrated urine, according to hydration levels in the body. At the start of renal failure, more & more water is need to expel toxins from the blood stream. Eventually, in chronic renal failure, a stage is reached where urine concentration does NOT change, regardless of hydration/dehydration, showing that the kidney is unable to function correctly.  Please note that some breeds have naturally high creatinine levels, and therefore if BUN is normal, this is NOT an indication of renal failure (e.g. greyhounds naturally have approximately 1.5 times higher levels than the “normal” creatinine level).

Causes include: kidney diseases such as polcystic kidneys, nephritis (e.g. with leptospirosis), blockage of ureter (tube from the kidney to the bladder), blockage of blood supply to the kidney, over-stimulation of the immune system (infections), amyloidosis, lower urinary tract diseases, some drugs, diabetes mellitus, lymphoma, hereditary (breeds such as Cocker Spaniels, German Shepherds, Cairn & Bull Terriers, Samoyeds are predisposed).

Treatment: Immediate rehydration by fluid therapy is needed in cases of dehydration (IV fluids or subcutaneous injection). Potassium maybe added to fluids or diet. Always make sure a dog with kidney failure has plenty of water available to keep them well hydrated as dehydration can be life-threatening. Restricted or low protein diet is advisable and special kidney formulas can be bought which are low in protein, phosphorus, calcium & sodium but with higher levels of potassium and omega 3 and omega 6 fatty acids. Erythropoeitin (EPO) may be needed for anemic dogs to stimulate red cell production. High blood pressure can be treated with anti-hypertensive drugs (e.g. elanapril). Phosphorous binding agents & Vitamin D can be used to stabilise blood calcium/phosphorous levels. Careful monitoring & vet vists for blood/urine tests, diet & treatment can slow down further deterioration immensely.

« Back to Glossary Index