Background facts and definitions Azotaemia is defined as increased concentrations of urea, creatinine or other non-protein nitrogenous compounds in blood. It may result from increased production or decreased excretion. Uraemia is the polysystemic toxic syndrome associated with the accumulation of abnormal concentrations of urine constituents in the blood. Uraemia involves alterations in the function of many organs and tissues. An understanding of the pathophysiology of uraemia provides the basis for the dietary management of chronic renal failure.
Renal disease refers to the existence of lesions in one or both kidneys.
The predominant presenting signs may vary with the specific region of the kidney affected. As with other disease processes, regression, persistence or advancement of the lesion may occur. Renal disease and renal failure are not synonymous terms, because the kidney has substantial functional reserve capacity. Thus, the presence of disease does not mean that dysfunction will be evident. Where renal failure due to primary renal disease has been present for an extended period of time, the term chronic renal failure is applied.