billy rubin

in the book the silence of the lambs, there is a scene where hannibal lecter walks senator martin (the father of the girl stuck in the pit) through the riddle of "billy rubin." buffalo bill's name is a pun on "bilirubin," the organic substance perhaps best known as the yellow tint in jaundiced individuals. i read the book after my sophomore year in high school, before i had seen the movie. jonathan demme cut out this scene from the movie, which i thought was a shame, but otherwise i found the film version to be almost as scary as the book. almost.

an elevated bilirubin level is a symptom of any number of physiologic abnormalities. in the context of hematology, elevated bilirubin levels indicate the breakdown of hemoglobin in the body, as can happen in settings of extravascular and intravascular hemolysis, i.e. the destruction of red blood cells either outside or inside the circulation. one component of hemoglobin in particular--protoporphyrin--is further broken down, resulting in unconjugated bilirubin. the liver typically conjugates bilirubin in order to produce bile, but excess unconjugated bilirubin cannot be processed fast enough by the liver nor excreted in the urine. as a result, it builds up in tissues, thereby yielding the yellowish tinge that characterizes jaundice and scleral icteri (yellowing of the eye).

the potential causes of this red blood cell destruction, as we were taught in class, are most likely either an autoimmune hemolytic anemia, where the body inappropriately produces antibodies against its own red blood cells, or hereditary spherocytosis, where a genetic defect results in the faulty construction of red blood cell membranes, causing RBCs to be abnormally small, inflexible (they look like tiny spheres under a microscope), and thus more susceptible to lysis. the test to differentiate between the two potential etiologies is the direct coombs test, which basically looks for antibodies against RBCs.

tomorrow: photos from the weekend