USMLE Forum Archives - USMLE Step 2 CK - IM 33
IM 33
TheOne - 03-07-07 09:09
A 60-year-old man has been having bloody bowel movements for 3 days. He reports to the emergency department, and while waiting to be seen he has another large evacuation of dark red blood. His blood pressure is 100/70 mm Hg and pulse is 120/min. He has a hemoglobin level of 10 mg/dL. In the initial evaluation a nasogastric tube is inserted and aspiration produces clear, yellowish fluid without blood. Digital rectal examination and anoscopy show that there is blood in the rectal vault, but does not identify a source. Which of the following is the most appropriate diagnostic study at this time?
A. Colonoscopy
B. Barium enema
C. Tagged red-cell study
D. Upper gastrointestinal barium studies
E. Upper gastrointestinal endoscopy
TheOne - 03-07-07 09:09
A 60-year-old man has been having bloody bowel movements for 3 days. He reports to the emergency department, and while waiting to be seen he has another large evacuation of dark red blood. His blood pressure is 100/70 mm Hg and pulse is 120/min. He has a hemoglobin level of 10 mg/dL. In the initial evaluation a nasogastric tube is inserted and aspiration produces clear, yellowish fluid without blood. Digital rectal examination and anoscopy show that there is blood in the rectal vault, but does not identify a source. Which of the following is the most appropriate diagnostic study at this time?
A. Colonoscopy
B. Barium enema
C. Tagged red-cell study
D. Upper gastrointestinal barium studies
E. Upper gastrointestinal endoscopy
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#3
Re: IM 33 kingkong - 03-12-07 02:10 proceed with colonoscopy to rule out colon pathology, if negative then only small intestine can be the source for which tagged red cell study is quite sensitive and can localise the bleed.please explain if incorrect.
#4
Re: IM 33
TheOne - 03-21-07 15:21 The correct answer is C. The clear aspirate at a time when he is actively bleeding indicates a source distal to the ligament of Treitz. Colon is the most likely site, but it could be small bowel. Tagged red-cell study should provide an idea of the region where the blood is pooling and set the stage for an arteriogram if active extravasation is demonstrated.
Colonoscopy (choice A) might appeal to some, but as a rule endoscopy of the colon at the time of active bleeding is unrewarding because the blood comes from higher up, obscuring the view as the instrument is advanced.
Barium studies, either from above (choice D) or below (choice B), are contraindicated at the time of active bleeding. Barium gets in the way of other, more productive studies.
The upper gastrointestinal is not the source of bleeding, and thus endoscopy of that area (choice E) will not help.
#7
Re: IM 33 babbu5508 - 07-06-10 23:14 A. Colonoscopy..large evacuation of dark red blood,nasogastric tube is inserted and aspiration produces clear, yellowish fluid without blood..point to colonic disease
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