A retrospective study of 60 cases of eccentrocytosis in the dog

Eccentrocytes are RBCs that appear in a peripheral blood smear to have their hemoglobin shifted to one side of the cell. This abnormality, which is confined to the RBC membrane and cytoskeleton, is induced by oxidative damage. Eccentrocytes have been reported rarely in dogs and are associated with onion and garlic ingestion and the administration of oxidant drugs.

The purpose of this study was to describe the occurrence and severity of eccentrocytosis in dogs and the diseases or disorders associated with eccentrocytes.

Detailed history, and results of physical examination, CBC, biochemical and coagulation profiles, and urinalysis from all canine patients admitted during a 2.5-year period were evaluated. Eccentrocytes, when observed, were graded 1+ (few) to 4+ (many). The severity of eccentrocytosis was compared with that of anemia and reticulocytosis.

Eccentrocytes were found in blood smears from 60 of 4251 dogs (1.4%) and were associated with mild to moderate anemia in 40 (66.6%) of the cases. Eccentrocytosis was found in 16 (26.6%) dogs with drug administration, 11 (18.3%) with presumptive onion and garlic ingestion, 8 (13.3%) with vitamin K antagonist intoxication, 7 (11.6%) with ketoacidotic diabetes, 5 (8.3%) with T-cell lymphoma, 4 (6.6%) with severe infections, 1 (1.6%) with compensated diabetes mellitus, and 8 (13.3%) with other conditions. Certain dog breeds, such as Whippet, Boxer, and English Setter, and young dogs seemed to be overrepresented.

We describe, for the first time, associations between eccentrocytes and diabetes mellitus, T-cell lymphoma and vitamin K antagonist intoxication in dogs. The significance of eccentrocytes should not be underestimated, because they can be a signal of an oxidative process.