Changes

The history may include administration of an equine-derived biologic product, often four to six weeks prior to the onset of clinical signs.  They are generally sudden in onset and rapidly progressive.  

The history may include administration of an equine-derived biologic product, often four to six weeks prior to the onset of clinical signs.  They are generally sudden in onset and rapidly progressive.  

Signs may range from mild lethargy or inappetance to signs of acute or chronic hepatic failure. They may be non-specific such as depression, anorexia or weight loss. Affected horses are often severely icteric and may pass dark urine due to the presence of bilirubin. Signs relating to hepatic encephalopathy may be present, such as head pressing, apparent blindness, yawning or aimless wandering. The course of the disease is usually around five days, with death ususally occuring within ten days.  

Signs may range from mild lethargy or inappetance to signs of acute or chronic hepatic failure. They may be non-specific such as depression, anorexia or weight loss. Affected horses are often severely icteric and may pass dark urine due to the presence of bilirubin. Signs relating to hepatic encephalopathy may be present such as head pressing, apparent blindness, yawning or aimless wandering. Dermatological signs such as photosensitisation or pruritus may also be seen. The course of the disease is usually around five days, with death ususally occuring within ten days.  

Mild forms of the disease have also been reported, characterised by a mild malaise and increased serum hepatic enzyme concentrations.  

Mild forms of the disease have also been reported, characterised by a mild malaise and increased serum hepatic enzyme concentrations.  

In several studies, biopsy is considered as the ‘gold standard’ technique for hepatic disease diagnosis. Biopsy is usually performed on the right hand side, between the twelth and fourteenth intercostal spaces. A coagulation profile is often performed prior to performing the procedure.  

In several studies, biopsy is considered as the ‘gold standard’ technique for hepatic disease diagnosis. Biopsy is usually performed on the right hand side, between the twelth and fourteenth intercostal spaces. A coagulation profile is often performed prior to performing the procedure.  

==Pathology==

==Pathology==

Post mortem examination often shows the liver to be enlarged and pale with rounded edges. Generalised icterus is often present. Histologically there may be centrilobular necrosis with mononuclear cell accumulation within the portal triads. Contusions, lacerations or fractures may be present if the disease has had a violent clinical course.  

Post mortem examination often shows the liver to be enlarged and pale with rounded edges. Generalised icterus is often present. Histologically there may signs of acute  be centrilobular to midzonal necrosis with mononuclear cell accumulation within the portal triads. Contusions, lacerations or fractures may be present if the disease has had a violent clinical course.