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Acta sci. vet. (Impr.); 41(supl.1): Pub. 19, 2013. tab, ilus

Artigo em Português | VETINDEX | ID: biblio-1372656

Resumo

Background: Leukemias are malign neoplasias of the hematopoietic precursor cells from the bone marrow. These neoplastic cells may or may not reach the blood circulation. Leukemias are classified as lymphoid or myeloid depending on the leukocyte cell lineage affected. In addition, leukemias are classified as either acute or chronic based on their cellular differentiation and proliferative aggressiveness. The leukemias from lymphoid cells that affect dogs include acute lymphoblastic leukemia and chronic lymphocytic leukemia. This paper describes the clinical and laboratorial findings of a case of acute lymphoblastic leukemia in a female dog. Case: A seven-year-old female mixed-breed dog was referred to the Veterinary Hospital of the Universidade Federal Rural do Semi-Árido (UFERSA), Mossoró, State of Rio Grande do Norte, Brazil, for apathy, anorexia, weakness and weight loss. The clinical examination confirmed the apathy and weakness. The mucous membranes were pale, the body temperature was 40.5°C, the heart rate was 120 bpm, the capillary refill time was 2 s, and no abnormalities were found on auscultation. Diagnostic laboratory tests were completed, including a serum test for canine leishmaniasis, a serum biochemistry panel, a complete blood cell count, and a bone marrow analysis. The canine leishmaniasis serology (enzyme-linked immunosorbent assay and indirect fluorescent-antibody test) was negative. The serum biochemistry panel revealed an increased level of aspartate aminotransferase (AST - 56.0 U/l), hypocalcemia (6.9 mg/dL), hypoalbuminemia (1.91 g/dL), hypobetaglobulinemia (0.51 g/dL), hypergammaglobulinemia (2.91 g/dL), and a decreased albumin/globulin (A/G) ratio (0.41). The observed hematological changes included a normocytic normochromic anemia (RBC = 2.55 x 106/mm³ , hemoglobina = 5.8 g/dL, PCV = 18%), leukocytosis (332,800/mm³) with a left shift (3,328/mm³), eosinopenia (0), monocytosis (6,656/mm³), lymphocytosis (89,856/mm³) with a pronounced presence of lymphoblasts (226,304/mm³) and thrombocytopenia (10 x 103/mm³). The blood smear evaluation revealed anisocytosis, polychromasia, hypochromia, giant platelets, smudge cells and lymphoid cells showing predominantly cytoplasmic basophilia, coarse nuclear chromatin, atypical nucleoli, asynchrony of cell maturation and degenerative cytoplasmic vacuolization, and lymphocytes with donut-shaped nuclei. The analysis of a sternal-puncture bone marrow sample revealed that the bone marrow was diffusely occupied by neoplasic lymphoblasts. Discussion: The anemia and thrombocytopenia observed in this female dog can be attributed to the growth of neoplastic cells in the bone marrow. Another finding was the presence of smudge cells, which are broken degenerated leukocytes, and the presence of these cells in large numbers has been described in humans with chronic lymphocytic leukemia or acute lymphoblastic leukemia. The observed hypoalbuminemia, hypergammaglobulinemia and reduced A/G ratio are probably due to the infl ammatory process stimulated by the leukemia. In fact, albumin is a negative acute phase protein, while an increased production of antibodies results in the increased γ-globulins. The prognosis for acute lymphoblastic leukemia is grave, as it is typically rapidly fatal. In humans, the occurrence of hypocalcemia and large number of smudge cells in cases of acute leukemia indicates a worse prognosis. In fact, this patient died one week after her clinical presentation.

Biblioteca responsável: BR68.1