Martin is a 62 year old gentleman who presents to your rural emergency department reporting blood in his stool. He has a history of constipation. He denies any current abdominal pain, nor any presyncope or syncope. His vital signs are as follows: HR 78, BP 110/82, RR16, O2 99% RA.
How do you tell on history whether this is potentially an upper vs. lower GI bleed?
What anatomical structure differentiates an upper GI bleed from a lower GI bleed?
Name 2 risk factors that may predict a more serious GI bleed.
List 3 causes for upper GI bleed and 3 causes of lower GI bleed.
What are 3 lab tests you would want to obtain?
Upper GI bleeds often appear as melena (dark black stools) due to digestion of the blood during gut transit vs. lower GI bleeds usually presenting as hematochezia (bright red blood). However, brisk upper GI bleeds may present as hematochezia.Upper GI bleeds may have hematemesis (vomiting bright red blood) or coffee-ground substance.
Always consider the potential etiology and ask about appropriate risk factors. Both upper and lower GI bleeds may present with rash, jaundice, abdominal pain.
Clinical tip: In practice, recognize 75% of GI bleeds are upper GI bleeds.
Exam tip: Don't forget to ask about foods or medications that may falsely change the color of your stool (e.g. iron, beets, liquorice, pepto-bismol)!
Ligament of Treitz
- Previous GI bleed, esp if required ICU admission
- Anticoagulant use
- Alcohol abuse
- NSAID use
Upper GI bleed:
Peptic ulcer disease, esophageal varices, mallory-weiss tear, gastritis, esophagitis, AVM (Arteriovenous Malformation), gastric cancer or esophageal cancer, epistaxis
Lower GI bleed:
Colitis, hemorrhoids/fissure, colon cancer, diverticular disease, angiodysplasia
- Blood Type
Exam tip: Be sure you are listing LAB tests and not imaging if the question specifies so. Also, remember you need to be SPECIFIC! "CBC" and "coagulation studies" are not acceptable. You must state entities such as hemoglobin separately. Also, Imaging such as endoscopy or abdominal x-rays may be useful too but that isn't what the question is asking.
Clinical tip: Given that the patient is stable, a blood type test may be appropriate. But if the patient were crashing, you may want to cross & match blood which will ensure that blood is available if you need it for transfusion. Also recognize that in acute GI bleeds, the hemoglobin may still appear normal despite significant blood loss.