Hepatoencephalopathy syndrome due to Cassia occidentalis (Leguminosae, Caesalpinioideae) seed ingestion in horses.
Authors: Oliveira-Filho J P, Cagnini D Q, Badial P R, Pessoa M A, Del Piero F, Borges A S
Journal: Equine veterinary journal
Summary
# Editorial Summary: *Cassia occidentalis* Seed Poisoning in Horses An outbreak affecting 20 mares consuming ground corn contaminated with 8% *Cassia occidentalis* seeds revealed the severity of this legume's hepatotoxic effects, with 60% mortality occurring either acutely or within 12 hours of clinical onset. Necropsy and histopathological examination of affected animals consistently demonstrated pericentrolobular hepatocellular necrosis and cerebral oedema, alongside large quantities of undigested seeds in the large intestine, establishing the causal link between seed ingestion and the clinical syndrome. Clinical presentations ranged from severe hepatoencephalopathy with sudden death to milder cases of depression and inappetence that responded to treatment, indicating variable dosage effects or individual susceptibility. Given the plant's potential to contaminate grain supplies and the rapid progression to fatal hepatic failure, feed suppliers and yard managers must implement rigorous quality control measures to prevent seed contamination, whilst veterinary surgeons should maintain *Cassia* poisoning as a differential diagnosis in cases of acute hepatoencephalopathy, particularly where multiple animals present simultaneously or sudden death occurs without premonitory signs.
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Practical Takeaways
- •Screen all grain and concentrate suppliers for potential Cassia occidentalis contamination; this plant can cause rapid, fatal hepatoencephalopathy at contamination levels as low as 8% in feed
- •Include hepatoencephalopathy from plant toxicity in differential diagnoses when horses present with acute depression, inappetence, and neurological signs, especially with feed-related onset
- •Implement strict quality control on purchased feeds and ground grains to prevent contamination; sudden deaths in groups of horses should prompt feed analysis
Key Findings
- •20 mares poisoned by consuming ground corn contaminated with 8% Cassia occidentalis seeds; 12 died and 8 survived with mild signs
- •Hepatocellular pericentrolobular necrosis and cerebral oedema were the primary histological findings
- •Large numbers of seeds were consistently found in the large intestine at necropsy
- •Clinical signs of hepatic encephalopathy (depression, appetite loss) occurred with sudden death in some cases within 6-12 hours of sign onset