Metabolic acidosis is a pathological condition characterized by the lowering of blood pH (excessive acidity of the blood), which may be due to the reduction of buffer substances (bicarbonates) or to an excess of acids in the body. In dogs and cats with chronic kidney disease (CKD) and renal insufficiency, metabolic acidosis causes a deterioration in quality of life and contributes to aggravate sensory depression, muscle weakness, fatigue, nausea and reduced appetite due the accumulation of uremic toxins. Metabolic acidosis also causes a notable increase in protein catabolism which is responsible (together with lack of appetite) of the loss of muscle mass of the patient. Dogs and cats with renal failure and metabolic imbalances will then have a worse quality of life resulting depressed, anorectic and showing a progressive deterioration of their body condition score. Because of the above, prognosis gets worse and there is a high risk of mortality due to uremic crisis. It is noteworthy that many patients with chronic kidney disease and metabolic acidosis significantly improve their quality of life when the latter is corrected, although they maintain blood creatinine value unchanged.
An extremely high percentage of dogs and cats with chronic kidney disease (CKD) develop metabolic acidosis in the advanced stages of the disease. If only 10% of patients have metabolic acidosis when serum creatinine is below 3 mg / dL, the percentage rises to 60% when creatinine is above 4-4.5 mg / dL.
Strategies to control acid-base imbalance depend on its severity and on the patient's clinical situation. Stable patients with moderate metabolic acidosis can benefit from renal diets, which are slightly alkalizing. If the situation is more severe, a specific therapy should be set: sodium bicarbonate, to be administered mixed with food, is the most widely used product, but it is the Veterinarian who will identify the most suitable therapy other than schedule patient’s follow ups.
There is unanimous agreement a therapy to control metabolic acidosis from renal causes is effective in improving both the quality of life and survival time of patients with chronic kidney disease.