Clinical and diagnostic features of portosystemic shunt in a foal.

This study is about a Quarter Horse filly diagnosed with a portosystemic shunt, a rare health issue among large animals, with symptoms including depression, blindness, and ataxia. After regular diagnostic methods failed to confirm the condition, more specialized diagnostic techniques were applied for confirmation but all medical treatments were unsuccessful, leading to the foal’s euthanization.

Background

• Portosystemic shunt is a medical condition where the host’s blood flow bypasses the liver, which is unusual and can lead to several health problems. While it’s more common in small animals like dogs and cats, it’s rare in large animals like horses.
• An unusual case of a 6-month-old Quarter Horse filly with portosystemic shunt was presented in this study. The symptoms included a sudden onset of apparent blindness, depression, lethargy, and ataxia.

Diagnosis

• The initial diagnosis based on clinicopathologic test results showed slightly high gamma-glutamyl transpeptidase activity and serum total bilirubin concentration. These suggest a possible liver malfunction.
• Additionally, prolonged sulfobromophthalein half time and high plasma ammonia and serum bile acid concentrations were further indications of abnormal liver functionality.
• A percutaneous liver biopsy was performed, revealing hepatocyte atrophy and many small arterioles in the portal triad area. These histopathologic findings indicated problems in the liver’s histological structure.
• The diagnosis of portosystemic vascular anomaly was initially made based on the foal’s history, clinical findings, and clinicopathologic abnormalities.

Confirmation and Treatment

• To confirm the presumptive diagnosis, nuclear hepatic scintigraphy and operative mesenteric portography were performed. These are advanced imaging techniques that provide information about the structure and functionality of the liver.
• Unfortunately, the foal’s condition did not improve despite medical treatment. Hence, due to the severity of the condition and poor prognosis, euthanasia was the final decision.

Conclusion

• The occurrence of a portosystemic shunt in a foal emphasizes the need to consider this medical condition in foals showing certain neurologic abnormalities, even though it’s rare in large animals.
• The paper suggests ruling out more common causes of neurologic issues in foals, such as trauma, vertebral body abscesses, brain abscesses, and meningitis, before diagnosing portosystemic shunt.