A hematogenic pleuropneumonia caused by postoperative septic thrombophlebitis in a Thoroughbred gelding.

The research study examines a case of pleuropneumonia in a 7-year-old Thoroughbred gelding horse that was triggered by postoperative septic thrombophlebitis. The condition emerged as a severe complication following colic surgery, demonstrating symptoms like lethargy, fever, inappetence, and diarrhea.

Background and Clinical Signs

• The Thoroughbred gelding horse was initially admitted for treatment of colic at the Equine Hospital of the Korea Racing Association.
• Due to a large and persisting cecal impaction, a celiotomy and large colon enterotomy were carried out.
• Post-surgery, the horse exhibited signs of distress such as lethargy, fever, lack of appetite and diarrhea, indicating a possible complication.
• These symptoms persisted and worsened over time, resulting in the horse’s death on the sixteenth day of its hospitalization.

Diagnostic Examination and Findings

• On the eleventh day after surgery, the jugular veins exhibited significant thrombophlebitis, a disorder characterized by blood clot formations in the vein accompanied by inflammation.
• Physical examinations showed the horse was febrile (with fever), tachycardic (elevated heart rate), and tachypnoeic (excessive rapid breaths). The horse also exhibited an increase in thoracic excursion but did not demonstrate any abnormal lung sounds. There was no cough or nasal discharge.
• In the hematology report, a neutrophilic leukocytosis was noted, which means an increase in the number of white blood cells (neutrophils) in the blood, often indicative of an infection or inflammation.
• The plasma fibrinogen level was also found to be elevated, which suggests the presence of an inflammatory condition.

Necropsy and Histopathological Examination

• Post-mortem examination (necropsy) revealed the presence of fibrinopurulent fluid, indicative of an infection, in the thoracic cavity.
• Further, there were firm adhesions between the visceral pleura and the thoracic wall, indicating inflammation and possible infection.
• Notably, thrombi formations in both jugular veins were discovered, which likely developed from the insertion point of the IV catheter.
• Microscopic examination (histopathology) of the lung tissue showed fibrinopurulent inflammation and vascular thrombosis. The pleura displayed edematous thickening and severe blood congestion.

Conclusions

• The pathological and clinicopathological findings suggest that the horse suffered from septic thrombi associated with septic thrombophlebitis.
• These septic thrombi presumably metastasized into pulmonary circulation, getting lodged in the lung tissue and causing pleuropneumonia.