Renal Disease—Case-Based Approach to Acute Renal Failure, Chronic Renal Failure and Protein-Losing Nephropathy

The most consistent presenting complaint for patients with chronic renal failure (CRF) and protein-losing nephropathy (PLN) is polyuria/polydipsia (PU/PD), though occasionally the owner does not recognize these clinical signs. Other historical findings for chronic renal failure may include weight loss and decreased appetite. Intermittent vomiting may be seen if secondary uremic gastric ulcers are present. In many cases, a CRF patient will be asymptomatic (other than PU/PD) until dehydration (potentially due to an unrelated cause) leads to decompensation, leading to a more acute history from the owner’s perspective. Although many PLN patients are asymptomatic early in the course of disease, history may include weight loss, PU/PD, lethargy, signs related to secondary CRF, and/or signs associated with an underlying cause (e.g., lameness). Occasionally, an animal with PLN will present with a distended abdomen because of ascites or dyspnea secondary to pleural effusion; these clinical signs result from a low colloid oncotic pressure secondary to hypoalbuminemia. While CRF and PLN can show up as an incidental finding on annual well-check bloodwork, the patient with acute renal failure (ARF) generally presents acutely ill. Common findings with acute renal failure may include sudden onset of lethargy, anorexia, and/or vomiting. Unlike chronic renal failure patients who are usually polyuric, acute renal failure patients are frequently oliguric or anuric. Patients that are oliguric or anuric usually have a poorer prognosis than ARF patients that are polyuric.