The case of a mare used for polo is reported. The animal showed clinical signs of soft lameness of the hindlimb, evolving to ataxia and gluteal muscle atrophy, with aorto-iliac thrombosis (AIT). The patient was treated with the suspect of equine protozoal myeloencephalitis (EPM), due to the resemblance of clinical signs. Cerebrospinal fluid analysis was negative for antibodies against Sarcocystis neurona. The transrectal examination indicated a mass in the left aorto-iliac bifurcation. In the ultrasonographic evaluation, a hyperechoic image adhered to the vascular endothelium was observed, suggesting (AIT), occupying 70% of arterial lumen. The present article has the objective of pointing out the importance of the differential diagnosis between AIT and EPM in horses with ataxia in hindlimbs and muscular atrophy.
equine; aorto-iliac thrombosis; equine protozoal myeloencephalitis; differential diagnosis
