CASE EXAMPLE: Urinalysis Case Number: 1
Signalment: Two‐year‐old spayed female Weimaraner dog.
History and Physical Examination: She has had pinkish‐to‐brown urine observed by the owners for at least six months. She is normal in every other respect, as is her physical examination. She has had no clinical urinary tract signs.
Interpretation of Urinalysis: The brown color to the urine is often due to the presence of hemoglobin oxidation products or myoglobin in the urine. Since there are TNTC RBC, the color is attributed to RBC and oxidation of hemoglobin. The urine is well concentrated at 1.039 USG. The pH of 7.0 could be in part accounted for by the amount of bleeding into the urine (plasma pH of 7.4). The 2+ protein on the dipstrip is likely from the proteins in the numerous RBC and plasma entering the urine. The rare granular cast per LPF is considered normal in the face of the 1.039 USG. The mild increase in WBC is most likely from the entry of blood into the urine; less likely it is from inflammation. The squamous epithelial cells are not of concern as they are almost always contaminants from the lower urogenital tract especially in samples collected during voiding or catheterization.
Hematuria is the most important finding in this urinalysis. There is a high amount of occult blood on dipstrip and RBC during microscopy. The origin of the RBC cannot be determined on findings from the urinalysis alone.
Further Diagnostics and Assessment: The finding of painless hematuria usually indicates upper urinary tract disease (kidneys, ureters). Differential diagnosis for painless hematuria should include renal neoplasia, nephrolithiasis, renal pelvic blood clot from trauma, and benign essential renal hematuria. Neoplasia is unlikely in a well dog with hematuria of this duration. Benign essential renal hematuria is the most likely consideration at this point.
A hemogram was normal with the exception of a mild microcytic anemia attribute to the chronic blood loss. Routine serum biochemistry was normal. Urine culture on a sample obtained by cystocentesis was negative.
Urinary tract imaging with radiographs and ultrasonography was normal. Urethrocystoscopy revealed no anatomical abnormalities, but bright red blood was seen from a urine jet emanating from the left ureteral orifice.
No treatment to interrupt the renal bleeding was provided. Iron supplementation over the next six months resulted in resolution of the microcytic anemia.
Final Diagnosis: Benign essential renal hematuria.
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