Like in humans, signs of liver disease are not usually seen until there is a significant decrease in liver function (70-80%). Sometimes we only see general unspecific signs of sickness and it is not until we do further testing that we can identify where the problem is coming from. In a number of cases liver disease is identified secondary to investigation of other ongoing problems that required a blood test.
When liver disease is identified, the most reliable way of gaining information about prognosis, appropriate treatment and the potential cause of the liver disease is by performing a tissue biopsy. Although the idea of having a biopsy may sound very invasive, it is a relatively quick procedure that is performed at the clinic; the horse is restrained in stocks and given intravenous sedation.
Ultrasound of the abdomen is performed on the right hand side, between the ribs, to visually assess the liver and identify a suitable area to be sampled. Most liver disease in horse is generalised and affects the whole organ, however if an area of liver look abnormal on ultrasound, this may be sampled specifically.
Once a suitable location has been identified, the area is clipped and aseptically prepared. Local anaesthetic is infiltrated into the skin and underlying tissue. A scalpel blade is used to make a stab incision in the skin and the biopsy needle is then introduced through the incision into the horse’s liver. The biopsy needle is then be “fired” to collect a sample. The sample is then placed in a pot of formalin to preserve it so it can be sent to a laboratory. The laboratory then performs a histopathological examination of the tissues which looks at the cellular make up of the tissue and a score between 0-14 is assigned depending on the severity of disease.
Check out our video below demonstrating how our vets perform a livery biopsy in our Plum Park clinic.