Evaluation of erythrocyte dysmorphism in dog urine

Avaliação do dismorfismo eritrocitário em urinas de cães

ABSTRACT:

Glomerulopathy is an important cause of kidney disease in dogs. Diagnosis is based on anamnesis, clinical examination, and complementary tests and can be complex and costly depending on the stage of the disease. Morphological evaluation of erythrocytes observed during urinalysis is frequently conducted for humans, which may help identify kidney damage in animals with kidney disease - individuals with glomerular disease present with erythrocyte dysmorphism, particularly the presence of erythrocytes recognized as acanthocytes. Animal studies are limited, and their results are often contradictory. Thus, the objective of this study was to identify the different populations of isomorphic and dysmorphic red blood cells (RBCs) present in the urine of dogs and to compare the bright-field and phase-contrast optical microscopy techniques in identifying morphological changes in RBCs during urinalysis. A total of 40 samples were selected from dogs with microscopic or macroscopic hematuria from routine care at Federal Rural University of Pernambuco Veterinary Hospital and were sent to the hospital’s Veterinary Clinical Pathology Laboratory. Physical, chemical, and sediment examinations were conducted. Subsequently, RBCs were evaluated and differentiated using bright-field and phase-contrast microscopy. In dog urine samples, it was possible to identify all populations considered isomorphic and dysmorphic that are described in humans. Among those considered isomorphic, normal RBCs, annulocytes, and echinocytes were observed, whereas stomatocytes, acanthocytes, codocytes, ghost cells, knizocytes and cells with no defined names (other) were found among the dysmorphic forms. No significant difference was observed between the two microscopic techniques used to differentiate and classify erythrocytes. Therefore, it is possible to identify and differentiate the morphological alterations found in RBCs in dogs’ urine. Compared with a phase-contrast microscope, a conventional optical microscope can be used without any detrimental effects, thereby facilitating the use of this technique in the laboratory routine, as it is cost-effective. Further studies should be conducted to evaluate the sensitivity and specificity of the identification of erythrocyte dysmorphism as an early marker of glomerular lesions.

INDEX TERMS:
Glomerular injury; erythrocyte dysmorphism; erythrocyte isomorphism; dogs; urinalysis