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| Also known as:

| Also known as:

| '''Theiller's disease<br>

| '''Theiler's disease<br>

|}

|}

==Description==

==Description==

Equins Serum Hepatitis (ESH) leading to acute liver failure is most commonly associated with administration of an equine biologic product. This is usually tetanus antitoxin, but encephalitis vaccines and equine serum have also been implicated. Other possible hypotheses include alkaloid toxicity and mycotoxins. Several cases have been reported in which no biologic product had been administered, leading to the possibility that an infectious agent may be involved.   

Equins Serum Hepatitis (ESH) leading to acute liver failure is most commonly associated with prior administration of an equine biologic product. This is most commonly tetanus antitoxin, but encephalitis vaccines and equine serum have also been implicated. Other possible hypotheses include alkaloid toxicity and mycotoxins. Several cases have been reported in which no biologic product had been administered, leading to the possibility that an infectious agent may be involved.   

==Clinical Signs==

==Clinical Signs==

The history may include administration of an equine-derived biologic product, often four to six weeks prior to the onset of clinical signs. These may range from mild lethargy or inappetance to signs of acute or chronic hepatic failure. They are generally sudden in onset and rapidly progressive. The course of the disease is usually around five days, with death ususally occuring within ten days.  

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 be non-specific such as depression or anorexia. 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, excitement, yawning or aimless wandering.  

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, excitement, yawning or aimless wandering. 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.  

==Treatment==

==Treatment==

Affected horses should be housed in a quiet, darkened stable in order to minimise stimulation.

Affected horses should be housed in a quiet, darkened stable in order to minimise stimulation. Sedation may be required if signs of hepatic encephalopathy are present. If the horse is still able to eat, a low protein, high carbohydrate diet should be fed. The protein should be high in branched-chain amino acids.

==Prognosis==

==Prognosis==

The prognosis for horses with signs of hepatic encephalopathy is extremely poor with a mortality rate approaching 100%. Horses that survive for a week after the onset of clinical signs may recover. A fall in SDH is associated with a better prognosis.  

The prognosis for horses with signs of hepatic encephalopathy is extremely poor with a mortality rate approaching 100%. Horses that survive for a week after the onset of clinical signs may recover. A fall in SDH is associated with a better prognosis.  

==References==

==References==