Lower GI Bleed

Lower GI Bleeds: Pathogenesis and Clinical Findings
Lower GI Bleeds are intra-luminal GI tract bleeds that occur anywhere distal to the ligament of Treitz (transition between duodenum and jejunum)
Author: Yan Yu Reviewers: Michael Blomfield, Tony Gu, Jason Baserman, Jennifer Au Kerri Novak* * MD at initial time of publication
1. Family history of colorectal cancer (CRC)
Patient is at ↑ for CRC
If pt develops CRC, malignant tissue invasion of the colon wall could disrupt blood vessels causing bleeding
↑ Risk for lower GI bleeds
Esophageal varices
If bleeding is severe, the transit of blood through the GI tract can be rapid
Hematochezia
(bright red blood per rectum)
How do the 5 “Risk factors for lower GI bleeds” actually cause Lower GI Bleeding?
2. Liver cirrhosis 3. Blood clotting defect (genetic disorder, ASA use)
4. NSAIDS
5. Prior lower GI bleeds
Damaged liver tissue restricts
blood flow through liver
Portal hypertension
(high blood pressure in the veins running from the GI tract to the liver)
Rectal varices
Can bleed; but are rare
↓ synthesis of blood clotting factors (i.e. fibrinogen)
↓ Prostaglandin synthesis (systemically)
↓ Epithelial protection along entire GI tract
Makes GI tract lining more likely to bleed
↓ clotting ability of the blood
Epithelium of the lower GI tract is unstable
Splenomegaly
(blood backing up and enlarging spleen)
Large spleen sequesters platelets
Ask the patients about these 5 risk factors when they present with a lower GI bleed!
Legend:
Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
Complications
Re-Published June 30, 2019 on www.thecalgaryguide.com