WBR0658

Author	[[PageAuthor::Serge Korjian M.D. (Reviewed by Serge Korjian)]]
Exam Type	USMLE Step 1
Main Category	Pathophysiology, Physiology
Sub Category	Gastrointestinal
Prompt	[[Prompt::A 45-year-old man admitted to the hospital for work-up of severe painless jaundice and icterus is found to have a massive obstructive pancreatic head mass almost completely blocking the bile duct lumen. Which of the following patterns would you expect in this patient? ]]
Answer A	A
Answer A Explanation	This pattern is usually not seen.
Answer B	B
Answer B Explanation	This pattern is typical of obstructive jaundice.
Answer C	C
Answer C Explanation	This pattern is usually not seen.
Answer D	D
Answer D Explanation	This pattern is usually not seen.
Answer E	E
Answer E Explanation	This pattern is typical of hemolytic type jaundice.
Right Answer	B
Explanation	[[Explanation:: Considering the patient's presentation, one would expect obstructive type jaundice. Obstructive jaundice is characterized by direct or conjugated hyperbilirubinemia as the conjugation mechanisms are not affected. It is rather the excretion of conjugated bilirubin through the bile is inhibited. As conjugated bilirubin builds up it increases in the blood. As it is water soluble (compared to unconjugated bilirubin which is not) it is excreted in large amounts in the urine, giving the urine a darker color. Urine urobilinogen is a product of bile recycling in the intestines. As the obstruction hinders bile release into the intestine, one would expect urine urobilinogen levels to decrease. Similarly, fecal stercobilin is related to bile content of the fecal material, so one would also expect the stercobilin levels to decrease and stool color to become much lighter. Educational Objective: Obstructive jaundice is characterized by direct (conjugated) hyperbilirubinemia with increase in urinary bilirubin and decrease in urobilinogen. References: Diagnosis of obstructive jaundice. Calif Med. 1970;112(5):44-58. Le T, Bhushan V. First Aid for the USMLE Step 1 2014. McGraw-Hill Medical; 2014.]]
Approved	Yes
Keyword	Obstructive jaundice, Bilirubin, Jaundice, Conjugated bilirubin, Pancreatic cancer
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