tailieunhanh - Chapter 043. Jaundice (Part 1)

Harrison's Internal Medicine Chapter 43. Jaundice Jaundice: Introduction Jaundice, or icterus, is a yellowish discoloration of tissue resulting from the deposition of bilirubin. Tissue deposition of bilirubin occurs only in the presence of serum hyperbilirubinemia and is a sign of either liver disease or, less often, a hemolytic disorder. The degree of serum bilirubin elevation can be estimated by physical examination. Slight increases in serum bilirubin are best detected by examining the sclerae, which have a particular affinity for bilirubin due to their high elastin content. The presence of scleral icterus indicates a serum bilirubin of at least 51 µmol/L. | Chapter 043. Jaundice Part 1 Harrison s Internal Medicine Chapter 43. Jaundice Jaundice Introduction Jaundice or icterus is a yellowish discoloration of tissue resulting from the deposition of bilirubin. Tissue deposition of bilirubin occurs only in the presence of serum hyperbilirubinemia and is a sign of either liver disease or less often a hemolytic disorder. The degree of serum bilirubin elevation can be estimated by physical examination. Slight increases in serum bilirubin are best detected by examining the sclerae which have a particular affinity for bilirubin due to their high elastin content. The presence of scleral icterus indicates a serum bilirubin of at least 51 iimol L mg dL . The ability to detect scleral icterus is made more difficult if the examining room has fluorescent lighting. If the examiner suspects scleral icterus a second place to examine is underneath the tongue. As serum bilirubin levels rise the skin will eventually become yellow in light-skinned patients and even green if the process is long-standing the green color is produced by oxidation of bilirubin to biliverdin. The differential diagnosis for yellowing of the skin is limited. In addition to jaundice it includes carotenoderma the use of the drug quinacrine and excessive exposure to phenols. Carotenoderma is the yellow color imparted to the skin by the presence of carotene it occurs in healthy individuals who ingest excessive amounts of vegetables and fruits that contain carotene such as carrots leafy vegetables squash peaches and oranges. Unlike jaundice where the yellow coloration of the skin is uniformly distributed over the body in carotenoderma the pigment is concentrated on the palms soles forehead and nasolabial folds. Carotenoderma can be distinguished from jaundice by the sparing of the sclerae. Quinacrine causes a yellow discoloration of the skin in 4-37 of patients treated with it. Unlike carotene quinacrine can cause discoloration of the sclerae. Another sensitive .