Glanzmann thrombasthenia in a 17-year-old Peruvian Paso mare.

The scientific research focuses on a case of Glanzmann Thrombasthenia (GT), a blood clotting disorder, detected in a 17-year-old Peruvian Paso Mare with a 3-year history of nosebleeds.

Details of Condition and Investigation

• The mare was inspected due to a nasal condition, specifically bilateral epistaxis, which had been persisting for at least 3 years.
• The mare was found to have mild anemia but its platelet count was within the normal range. Coagulation times were also found to be normal, indicating that there were no obvious signs of a systemic clotting disorder. A Coggins test was done which came back negative, ruling out equine infectious anemia.
• A detailed endoscopic examination was done which did not indicate any structural abnormalities in the nasal cavities, pharynx, larynx, trachea, or guttural pouches, which could have been potential case of the nosebleeds.
• The examination did, however, find petechiation in the nasal mucosa which are red or purple spots caused by small amounts of bleeding.

Diagnostic Testing and Findings

• Subsequent diagnostic tests revealed a prolonged cutaneous bleeding time which is a sign of episodic bleeding tendencies.
• The concentration of von Willebrand factor antigen was found to be normal. This is an important protein required for blood clotting.
• An abnormal clot retraction test was noted, indicating a problem with clot formation or stability.
• The failure of platelet aggregation in response to triggers was observed, implying that there was a functional disorder in the platelets of the mare.
• Genetic analysis was done which indicated the horse to be homozygous for a 10-base-pair deletion in the gene encoding glycoprotein IIb. This is significant as glycoprotein IIb is a key protein in platelets necessary for forming clots.

Conclusion and Implications

• The combination of these clinical signs and diagnostic results led to the diagnosis of GT which is caused by a structural defect in the glycoprotein IIb-IIIa complex found on platelets.
• It was concluded that GT should not be ruled out in horses with suspected dysfunctional platelets, regardless of their age. This was a significant finding as GT is a genetic disorder and this case was unique because of the mare’s older age at the time of diagnosis.
• These findings are important in that they expand our understanding of GT, helping to identify and manage this disorder more effectively in horses in the future.