CHAPTER 33: HEPATIC DISEASE
Introduction
The term “hepatic” or the prefix “hepato-” refers to the liver. The liver has digestive, metabolic, endocrine and detoxification function. It produces and secretes it into the proximal duodenum where it is used in the digestion of dietary lipids. The liver produces and secretes clotting factors that are essential for blood coagulation. It is involved with carbohydrate storage and metabolism, fat metabolism, protein deamination and the synthesis of non-essential amino acids and the plasma proteins. Functioning liver is essential for life, without it the blood becomes , digestion is impaired, metabolism of nutrients is impaired and the blood looses its ability to clot. In most circumstances only % of the liver is required to maintain the normal function of the body. This means that sixty to eighty percent of the liver must be damages before clinical signs of hepatic disease are apparent.
Common signs of hepatic disease include
, anorexia, weight loss, , diarrhea, intermittent fever, coaggulopathy and hepatic . Hepatic encephalopathy is the name given to central nervous system
disease that is caused by the buildup of toxins such as that are normally removed or neutralized by the liver. Signs of hepatic encephalopathy include dementia, head- pressing, wandering, circling, ataxia, dysphagia, inspiratory stridor and dyspnea. . The presence and concentrations of certain hepatic enzymes and secretions in the blood may be indicative of specific hepatic diseases or of general liver function. The enzymes of most interest in the horse are: The diagnosis of hepatic disease often includes gamma glutamyltransferase (GGT), an enzyme involved in amino acid production and metabolism aspartate aminotransferase (AST), an enzyme that is found in the mitochondria of cells that have high metabolic demands sorbitol dehydrogenase (SDH), an enzyme involved in carbohydrate metabolism in the liver lactate dehydrogenase (LDH), an enzyme that catalyzes the conversion of pyruvate into lactate concentrations are often used to indicate hepatic function as this pigment is a derivative of the breakdown of erythrocytes in the liver that is normally secreted into the intestines as a part of bile. Bile acid levels also indicate the liver’s ability to make and secrete bile into the small intestine.
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