Idiopathic immune-mediated polysynovitis in three horses.

The study investigates the symptoms, laboratory findings, and treatment outcomes of three horses suffering from immune-mediated polysynovitis, a condition characterized by joint inflammation due to immune response.

Research Subject and Symptoms

• The study involved three horses suffering from an immune-mediated condition termed polysynovitis, affecting multiple joints.
• The common symptoms across the subjects included weight loss, intermittent fever, lethargy, stiffness, and effusions (swelling) in multiple joints.

Laboratory and Histological Findings

• The laboratory tests showed anomalies like anaemia, leucocytosis (high level of white blood cells), hyperfibrinogenaemia (excess fibrinogen in the blood) and hyperglobulinaemia (high levels of globulins in the blood).
• The histological examination of the subjects showed suppurative, non-septic inflammation (pus-forming inflammation without infection) in at least two different joints in each horse.
• In one horse, presence of immunoglobulins (antibodies) was detected in the synovial membrane (lining of the joint), which further confirmed the immune-mediated nature of the inflammation.

Treatment and Outcomes

• The horses were treated with a combination of dexamethasone and azathioprine; both of these drugs have immune-suppressive properties.
• The horses responded well to the initial treatment; however, there were variances in the long-term outcomes. The first horse showed recurrence of the symptoms after discontinuing the cytotoxic drug and was maintained on azathioprine. The second horse was in the process of concluding a decreasing course of prednisolone (a steroid medication) 15 months after the initial examination.
• The third horse, unfortunately, had to be euthanized five months after the initial examination due to an unrelated injury.