Infarctive purpura hemorrhagica in a Thoroughbred mare

Abstract

A 19 year old Thoroughbred Mare presented to the Cornell Equine and Farm Animal Hospital (CE-FAH) with a chief complaint of what appeared to be severe exertional rhabdomyolysis. She had an acute onset of trembling and staggering, followed by painful episodes. Initial physical exam findings included tachycardia, hard painful muscles, focal areas of swelling and pigmenturia. Additional findings the following day included severe ventral and limb edema and petechiae on all of her mucous membranes and conjunctiva. Bloodwork abnormalities included icterus, a left shift with toxic changes, hypoproteinemia, hypoalbuminemia and greatly elevated CK and AST values. Streptococcus equi M protein titer was very high positive (1:12,800). She was diagnosed with purpura hemorrhagica and treated with intravenous fluid therapy, dexamethasone, ceftiofur and hydrotherapy. She initially showed signs of improvement but started to regress on the fourth day of treatment. After six days of treatment, the decision was made to euthanize her. Necropsy results revealed marked, severe multifocal thrombosis and purpura, but there was no evidence of previous or current Strangles lesions. This paper discusses the medical management of this case, as well as an overview of both classic and infarctive purpura hemorrhagica.