Urine and aspirated abdominal fluid from a five-year-old Collie dog were submitted to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) for a urine protein to creatinine ratio (UPC) and a fluid analysis and cytology. The UPC was 10.48. The protein in the abdominal fluid was 0.2 mg/dl. The ascites was due to the large loss of protein through the kidneys. Pre-renal and post-renal causes can be ruled out by various tests. The large amount of protein being lost in this case is most suggestive of a primary renal causes. A biopsy would be needed to identify the specific pathologic process.
Loss of protein can occur through the kidneys or intestinal tract or by a lack of production by the liver. Loss of protein through the kidneys can be pre-renal, renal or post-renal. Examples of pre-renal proteinuria include increased hemoglobin, myoglobin, or Bence-Jones proteins (from neoplastic plasma cells) in the urine. Renal proteinuria could result from functional or pathologic causes. Functional proteinuria can result from heat, stress, seizures, fever, or extreme exercise. Pathologic proteinuria usually results in the highest and most persistent levels of proteinuria. Causes include glomerulonephritis and amyloidosis. Post-renal proteinuria could be the result of urinary tract infections, inflammation, and hemorrhage (sources distal to the kidney).
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