Thus, it takes substantial hepatocellular damage to result in clinical liver dysfunction. The term liver function tests (LFTs) is a misnomer because these tests measure the levels of aminotransferases, alkaline phosphatase, and GGT in the blood, which measure hepatocellular damage rather than true liver function since the liver has tremendous overcapacity. GGT is found in biliary epithelia and hepatocytes, and is therefore a more specific marker for liver disease (4). Alkaline phosphatase, besides being found in the liver, is also present in kidney, bone, placenta, and intestine. The ALT and AST are formerly known as SGPT (serum glutamic pyruvic transaminase) and SGOT (serum glutamic oxaloacetic transaminase), respectively. It should be noted that these aminotransferases are also located in heart and skeletal muscle tissues, although alanine aminotransferase (ALT) is more specific to the liver than aspartate aminotransferase (AST) and has a longer plasma half-life (which makes an elevation of AST indicative of early hepatic damage). When this occurs, enzymes in these cells are released, which include the aminotransferases (aspartate aminotransferase and alanine aminotransferase), alkaline phosphatase, and gamma-glutamyl transpeptidase (GGT). The common theme is that there is injury or death to the hepatocytes. The anatomy and physiology of the liver is complex and outside the scope of this chapter, although its basic concepts are important to understand the pathophysiology of liver disease. Although viral hepatitis is well known, other diseases include autoimmune causes such as systemic lupus erythematosus, drug-induced causes such as isoniazid, and metabolic disorders such as Wilson disease, alpha-1-antitrypsin deficiency, tyrosinemia, Niemann-Pick disease type 2, glycogen storage disease type IV, cystic fibrosis, galactosemia, and bile acid biosynthetic abnormalities (3). Hepatitis is an inflammation of the liver and can be due to many different causes. This chapter will discuss some of the diseases that affect the liver, focusing on viral hepatitis. Therefore, diseases that damage the liver can have very detrimental effects on the body. It excretes bilirubin and biliverdin formed from heme in red blood cells from the reticuloendothelial system in different parts of the body (1,2). It also synthesizes bile and plays an important role in lipid metabolism.
The cytochrome P-450 system is responsible for the detoxification of many different compounds (e.g., drugs), and is important in the metabolism of steroid hormones and fatty acids. It manufactures proteins such as albumin, prothrombin, fibrinogen, transferrin, and glycoprotein from amino acids. It deaminizes amino acids into ammonia, which is then converted into urea. It also stores glucose in the form of glycogen, or converts it into fatty acids. It is the first to receive blood from the intestines through the portal vein. The liver performs many essential functions. Her blood work later returned positive for hepatitis A. On further questioning, it is discovered she ate at a restaurant one month ago where a worker was found to have hepatitis A. In light of her presentation, additional blood work is sent for anti-HAV IgM, HBsAg, anti-HBc, and HCV. Prothrombin time is 14.0 seconds (prolonged). AST 500, ALT 550, alkaline phosphatase 500, GGT 50, total bilirubin 13.5 (direct fraction 5.0). Electrolytes, BUN, and creatinine normal. Laboratory data: Normal CBC and reticulocyte count. The rest of her examination, including cardiac, pulmonary, and neurological systems, is normal. Her liver edge is palpable 5 cm below the right costal margin, and is moderately tender.
#Define scleral icterus skin
Her skin is jaundiced and there is scleral icterus.
She appears tired and ill-appearing, but is cooperative with her examination. She has had a 2.3 kg (5 pound) weight loss since her last visit 6 months ago. Her parents had refused her childhood vaccines.Įxam: VS T 38.4, P 85, RR 16, BP 100/70. She is not taking any medications other than ibuprofen for her fever. She is not sexually active and denies drug or alcohol use. She denies any coughing, upper respiratory symptoms, diarrhea, and dysuria. Her urine color is darker than normal, although she has not been drinking much fluid. She had two non-bloody, non-bilious episodes of emesis in the last two days and also has abdominal pain on her right side below the ribs, which has been getting worse. Her fever has been between 101 and 102 degrees, and occurs every day.
#Define scleral icterus update
This current third edition chapter is a revision and update of the original author's work.Ī 14 year old female patient comes to your office with a chief complaint of nausea, poor appetite, and fever for one week. The editors and current author would like to thank and acknowledge the significant contribution of the previous author of this chapter from the 2004 first edition, Dr.
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