Dr. Nguyen presented an interesting case of a male presenting with melanic stools that gave us the opportunity to review GI bleeds.
Upper versus Lower GI Bleeding
An acute upper GI bleed (UGIB) classically presents with hematemesis or melana. Etiologies include:
Varices/portal hypertensive gastropathy in liver disease or alcohol abuse
Peptic ulcer disease (Can be caused by H. pylori or NSAIDs)
Malignancy
Angiodysplagia
An acute lower GI bleed (LGIB) classically presents with hematochezia, unless there is right-sided colonic bleeding which more classically presents as melena. This can be from:
Diverticulosis
Vascular abnormalities (angiodysplagia, ischemia, radiation)
Inflammatory (infectious vs. IBD)
Malignancy
A JAMA rational clinical examination article described some findings that can help differentiate a severe upper GI bleed from a lower GI bleed. Findings that increase the chances of an UGIB include Melena (LR: 5.1-5.9), NG lavage with blood or coffee ground (LR: 9.6), and a BUN:creatinine ratio > 30 (LR: 7.5). Blood clots in the stool make a UGIB much less likely (LR: 0.05)
Management
When managing a suspected GI bleed, the following are critical steps:
IV access – Adequate peripheral access is needed. All patients should have two 18 gauge or larger catheters. Central access counts!
.Fluid resuscitation- This can be done with either LR or NS. Give fluids to meet the following physiologic endpoints (HR <100/min, SBP >100 mm Hg, and NO orthostatic symptoms).
Transfusion – Make sure the patient is type and crossmatched. The PRBC transfusion threshold is generally a hemoglobin of <7 but it can be higher if the bleed is very active (remember: it takes a while for the CBC to drop!) or if the patient is symptomatic.
Attention to any present coagulopathy- Any INR > 1.5 should be corrected with FFP in actively bleeding patients on anticoagulation therapy but do not delay endoscopy unless INR >3.0.
Anticoagulants, antiplatelets, NSAIDs and blood pressure medications are held in setting of acute GIB
Endoscopy
EGD is the preferred imaging modality for acute UGIB – high sensitivity and specificity for identifying bleeding lesions
Once a lesion is identified, therapeutic intervention can be done right away to achieve acute hemostasis and prevent recurrent bleeding. This includes banding, clipping, cauterization.
Other diagnostic tests include angiography, deep small bowel enteroscopy, and wireless capsule endoscopy
Colonoscopy is study modality of choice for acute LGIB: this allows for precise localization of bleeding, biopsy, and therapeutic intervention.
Disadvantages to colonoscopy is need for bowel preparation, which can be a limiting factor to a successful colonoscopy
Radiographic tests such as 99mTc tagged RBCs (most sensitive radiographic test for GIB) and CT angiography can be used, but only useful when there is active bleeding.
References
Hebert et al. “A multicenter, randomized, controlled clinical trial of transfusion requirements in critical care”. NEJM. 1999. 340(6):409-417
Kim et al. “Causes of Bleeding and Outcomes in Patients Hospitalized with Upper Gastrointestinal Bleeding.” J Clin Gastroenterology. 2013.
Rockall et al. “Risk assessment after acute upper gastrointestinal haemorrhage”. Gut. 1996;38:316-21
Srygley FD, Gerardo CJ, Tran T, Fisher DA. “Does This Patient Have a Severe Upper Gastrointestinal Bleed?” JAMA. 2012;307(10):1072-1079.
Villanueva et al. “Transfusion Strategies for acute upper gastrointestinal bleeding”. NEJM. 2013. 368(1):11-2.
MKSAP 17. “Chapter 8: Gastrointestinal bleeding”.
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