Differential Diagnosis of Jaundice
The yellow or greenish yellow staining of the blood plasma and body tissues, to which the clinical term jaundice has been applied, is due to an excessive amount of one of the normal constituents of the blood, viz., bilirubin.
To differentiate accurately the various causes of jaundice, one must understand something about the source, properties, and excretion of bilirubin.
Bilirubin is a product of the normal daily destruction of red blood cells which occurs at a surprisingly rapid rate, the estimated life of a red blood cell being from 4 to 30 days. As formed in the blood stream, bilirubin is strongly combined or attached to the blood proteins. To break up this combination with protein, the action of the liver cells or the presence of bile salts is required. When combined with protein, bilirubin cannot be excreted by the kidneys so that the liver normally acts as the only excretory organ of bilirubin to form the bile pigment of bile.
The liberation of the bilirubin from the protein is not completely understood but liberated bilirubin does not occur in the blood serum except in the presence of disease of the liver or bile ducts. The ease with which these two types of bilirubin can be distinguished by the so-called direct and indirect action of the qualitative van den Bergh reaction serves the very important purpose of immediately separating jaundice into two types:
Hyperbilirubinemia due to increased production.
Hyperbilirubinemia due to decreased excretion.
The first type must be. . .