Clinicopathologic findings in dogs with renal amyloidosis: 59 cases (1976-1986)

The medical records of 59 dogs with renal amyloidosis were reviewed. Most dogs with amyloidosis were greater than 6 years old, and females were affected more often than males. Beagles, Collies, and Walker Hounds were at increased risk, whereas German Shepherd Dogs and mixed-breed dogs were at decreased risk. Common historical findings were anorexia, polyuria, polydipsia, lethargy, vomiting, and weight loss. Common laboratory findings were leukocytosis, lymphopenia, nonregenerative anemia, hypercholesterolemia, azotemia, hyperphosphatemia, metabolic acidosis, isosthenuria, cylindruria, and proteinuria. Proteinuria was moderate to severe in most dogs, as assessed by qualitative determination of urine protein concentration, urine protein/urine creatinine ratio, and 24-hour urine protein excretion. Conservative medical management was of little value, and survival ranged from 3 to 20 months in 12 dogs for which this information was available. Moderate to severe diffuse global glomerular amyloidosis was detected in all dogs. Medullary amyloid deposition was multifocal and less severe, but was evident in most dogs. Secondary tubulointerstitial and glomerular lesions were mild or absent in most dogs. Thromboembolism was identified in approximately 14% of affected dogs, underlying inflammatory disease in 37%, and neoplasia in 20%. Laboratory indicators of renal function correlated poorly with histologic lesions, with the exception of glomerular amyloid deposition and "chronic renal disease" index with endogenous creatinine clearance.