A retrospective study of the aetiology of increased mean platelet volume in dogs presented to a small animal teaching hospital in Greece.

Background: The aetiology of increased mean platelet volume in dogs is currently uncertain. Our aim was to investigate the aetiology of increased mean platelet volume in dogs with and without thrombocytopenia.

Methods: The database of a teaching hospital was retrospectively searched for dogs with increased mean platelet volume (>14.4 fL) over a 3-year period. Complete blood counts were performed with an Advia 120 analyser. Cases with incomplete medical records or belonging to breeds known to be associated with macrothrombocytopenia were excluded.

Results: Sixty-six dogs were included, with Group 1 consisting of non-thrombocytopenic dogs (49/66, 74.2%) and Group 2 consisting of thrombocytopenic dogs (17/66, 25.8%). Diagnoses significantly differed between the two groups (p = 0.003). In Group 1, inflammatory/infectious diseases (69.4%) were the most common cause, followed by neoplastic diseases (8.2%) and diabetes mellitus (6.1%). Dogs in Group 2 were diagnosed with either inflammatory/infectious diseases (50.0%) or neoplastic diseases (50.0%). The small sample size- and a potential delayed haematological analysis of some of the blood samples, could have artifactually affected the mean platelet volume.

Conclusions: In dogs with thrombocytopenia and increased mean platelet volume, inflammatory/infectious or neoplastic diseases should be considered. In non-thrombocytopenic dogs, increased mean platelet volume is primarily associated with inflammatory/infectious diseases, with neoplasia and diabetes mellitus being infrequent causes.