What causes jaundice?
How are biliary obstruction and cholangitis diagnosed?
What are the best imaging modalities?
What treatment strategies should be employed in patients with biliary obstruction or cholangitis?
When should procedure or surgical intervention be considered in patients with cholangitis?
This chapter describes clinical conditions manifested as a result of acute or subacute biliary disease. Particular focus is on conditions that frequently present to the inpatient setting, including jaundice, which is frequently a symptom of biliary or liver disease, as well as acute obstruction or infection within the biliary tract.
Jaundice is a yellowish discoloration of the skin, the conjunctivae, and other mucous membranes caused by hyperbilirubinemia (56206090). Generally, the serum bilirubin level needs to exceed 2.5 to 3 times the upper limit of normal (0.5–1.0 mg/dL) before jaundice is apparent. Jaundice is typically recognized earliest under the tongue, followed by within the sclera (sclera icterus), prior to it manifesting in the skin. Jaundice usually results from a pathologic process that interferes with the normal metabolism and excretion of bilirubin (56206090). Physiologically, bilirubin is the product of the breakdown of the hemoglobin in senescent red blood cells. Splitting of the four pyrrole ring of heme produces biliverdin, which is then reduced to bilirubin. Water-insoluble bilirubin is transported from the spleen to the liver, where it is rendered more water soluble by conjugation to glucuronic acid. Conjugated bilirubin is excreted into bile and subsequently into the gut, where it is broken down by bacteria into urobilinogen, some of which is converted into stercobilinogen and excreted in the stool, and some of which is transported to the kidneys and excreted in the urine. The stools of patients with obstructive jaundice, who cannot excrete bilirubin into the gut, have pale stools and dark urine, the latter due to greater-than-normal urinary excretion of urobilinogen.
Cycling of bilirubin and its products through the liver, intestines, portal and systemic circulations, and kidneys. (B, bilirubin; G, glucuronide; UroB, urobilinogen).
Prehepatic jaundice results from any process that causes an increased rate of hemoglobin breakdown (hemolysis) (56206094). Congenital and acquired conditions cause hemolysis. Congenital conditions that lead to hemolysis include sickle cell syndrome, thalassemia, and spherocytosis; these conditions lead to increased breakdown of red blood cells and hemolysis. Infectious etiologies may lead to massive lysis of red cells, including the malaria parasite (Plasmodium falciparum causes blackwater fever). Iatrogenic causes of hemolysis due to various drugs can occur, and autoimmune hemolytic syndromes can also lead to prehepatic jaundice. More than 900 drugs, toxins, and herbs are known to cause liver injury, and more than 2000 deaths per year are attributed to this cause in the United States. The mechanisms of–and predispositions to–drug-related liver injury are complex. However, many of these reactions ...