Infarctive purpura hemorrhagica in five horses.

This study examines the cases of five horses that exhibited symptoms of muscle stiffness and colic and were exposed to Streptococcus equi. The researchers identified a severe form of purpura hemorrhagica, characterized by infarction of skeletal muscles. Potential therapy involves antimicrobial and corticosteroid treatment.

Introduction and Clinical Presentation

• The article begins by explaining the reason for examination of five horses that showed signs of muscle stiffness, colic, or both.
• All these horses had been exposed to a bacterium named Streptococcus equi within the last three weeks or had high levels of antibodies against M-protein, a surface protein of S. equi.
• The horses displayed signs of continuous colic-like pain and local areas of muscle swelling were observed on their bodies.

Treatment and Outcome

• Among the five, four horses had to be euthanized due to deteriorating conditions while the fifth horse responded positively to the treatment of penicillin and dexamethasone. The horse was treated with dexamethasone for three weeks, followed by a course of prednisolone for the next 10 weeks.

Diagnostic Findings

• The horses displayed a series of hematologic and serum biochemical abnormalities. These included neutrophilia (an increase in the number of white blood cells), hyperproteinemia (an excess of protein in the blood), hypoalbuminemia (a low level of albumin in the blood), and high serum creatine kinase and aspartate transferase activities which are markers of muscle and liver injury respectively.

Postmortem Examination

• Postmortem examination of the euthanized horses revealed extensive infarction (tissue death due to lack of blood supply) in the skeletal muscles, skin, gastrointestinal tract, pancreas, and lungs.
• The microscopic examination of the tissues showed leukocytoclastic vasculitis (a disease involving inflammation of small blood vessels) and acute coagulative necrosis, conditions that resemble tissue death due to lack of oxygen.

Conclusion

• The research thus concluded that these horses had a severe form of purpura hemorrhagica, a disorder similar to Henoch-Schönlein purpura observed in humans. This condition was characterized by infarction or cell death in skeletal muscles.
• The researchers suggest that recognizing the symptoms early on, such as local muscle swelling, abdominal discomfort, neutrophilia, hypoalbuminemia, and elevated serum creatine kinase activity improves the chances of successful treatment using antimicrobial and corticosteroid therapy.