Compare conditions

Put any two — or three — conditions side by side, adult or pediatric, to spot the look-alike differences fast, row by row.

Lower GI Bleed

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In one line

·Bleeding from anywhere in the gut below the ligament of Treitz (the first bend of the small intestine, right past the stomach).

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Normal physiology

·The colon and lower small intestine are supplied by branches of the superior mesenteric artery (feeding the right colon and small bowel) and the inferior mesenteric artery (feeding the left colon and rectum). These arteries split into smaller and smaller vessels that deliver oxygen-rich blood to the gut wall. The rectal veins drain blood back through two routes: the superior rectal vein into the portal system (toward the liver) and the middle and inferior rectal veins into the systemic circulation (toward the heart). This dual drainage is why bleeding from higher up can sometimes look like it is coming from below.

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What goes wrong

·Usually one specific structure in the lower gut starts bleeding: a pouch (diverticulum) that bulges out from the colon wall and tears a vessel, a tangle of fragile blood vessels (angiodysplasia) that leaks, a stretch of colon that lost its blood supply (ischemic colitis), an infection inflaming the lining (infectious colitis), an inflammatory condition flaring up (ulcerative colitis or Crohn disease), a polyp or cancer that erodes through vessels, or (in about 15 percent of cases) brisk bleeding from the upper GI tract (stomach or duodenum) moving so fast through the gut that it looks like a lower bleed.

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Hallmark signs

·Bright red or dark red blood in the stool (hematochezia)
·Racing heart (tachycardia) and low blood pressure when a lot of blood is lost quickly
·Feeling dizzy, weak, or like you might faint (orthostatic symptoms)
·Pale skin and inside of the eyelids look less pink (pallor)
·Tiredness and shortness of breath, especially if the bleed has been slow and steady
·Cramping or belly pain, sometimes on the left side
·Black, tarry stool (melena) if the bleed is in the right colon and moves slowly
·Blood mixed into diarrhea, or bloody mucus

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Red flags · escalate now

·Blood pressure under 100 systolic, heart rate over 100, or feeling faint when you stand — signs you have lost a dangerous amount of blood and need emergency fluids or transfusion
·Steady, heavy bleeding that does not slow down — this can empty your blood volume fast and needs urgent colonoscopy or angiography (dye X-ray of blood vessels) to find and stop the source
·New confusion, chest pain, or very pale, cold, clammy skin — your brain and heart are not getting enough oxygen because blood volume is too low; this is shock and requires immediate resuscitation
·Blood in the stool plus a recent colonoscopy or colon surgery — you may have a tear or bleeding vessel at the procedure site that needs urgent follow-up

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Workup

·Complete blood count (CBC) with hemoglobin and hematocrit
·Blood urea nitrogen (BUN) and creatinine
·Prothrombin time (PT/INR) and activated partial thrombrombin time (aPTT)
·Type and screen (or type and crossmatch if bleeding is brisk)
·Serum lactate
·CT angiography of the abdomen and pelvis (if bleeding is active and brisk)
·Colonoscopy (when bleeding has slowed or stopped)
·Nasogastric lavage or upper endoscopy (if BUN-to-creatinine ratio is high or clinical picture is unclear)

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Treatment

·Intravenous fluid resuscitation with normal saline or lactated Ringer's, followed by packed red blood cell transfusion to hemoglobin goal of 7–8 g/dL (or 8–9 g/dL if the patient has heart disease)
·Hold or reverse anticoagulants (warfarin, heparin, direct oral anticoagulants) and antiplatelet drugs (aspirin, clopidogrel) based on bleeding severity and agent type
·Colonoscopy with hemostatic intervention (endoscopic clip, band ligation, or thermal coagulation) once bleeding has slowed and the colon is prepared
·Interventional radiology angiographic embolization if colonoscopy fails, is not possible, or bleeding is too brisk to see with a scope
·Surgery (segmental colectomy) if bleeding does not stop with endoscopy or embolization, or if the patient becomes unstable despite resuscitation
·Stop nonsteroidal anti-inflammatory drugs (NSAIDs like ibuprofen or naproxen) and treat the underlying cause (antibiotics for colitis, colonoscopy surveillance for polyps, surgery for cancer)

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NCLEX trap

·Always do a rectal exam and check hemoglobin, BUN, and creatinine. Hemorrhoids are common, but so are diverticula (small pouches in the colon wall) and abnormal blood vessels in older adults. A lower GI bleed can look like hemorrhoids but be something much more serious.
·The order matters: make the patient safe, figure out why they're bleeding, then fix it. Stop the medicine causing the bleed (blood thinner or NSAID like aspirin or ibuprofen) before — or while — giving transfusions. Otherwise the bleed keeps going even as you replace the blood.
·In a lower GI bleed, a fast heart rate is the body's way of saying 'I'm losing blood and pumping harder to keep up.' The treatment is fluids and blood transfusions, not a drug to slow the heart. Slowing the heart when the patient is already losing blood makes shock worse because the body can't compensate anymore.
·If the stool is bright red and the patient has no vomiting or belly pain, a lower GI bleed is more likely. Rule out upper bleeding with a BUN-to-creatinine ratio first. Save EGD for when an upper bleed is actually suggested by the history or labs.
·In a lower GI bleed, bleeding stops on its own in 80% of cases — but it comes back in 20%. You have to find the source (diverticulum, abnormal vessel, polyp, or cancer) so it can be treated before it bleeds again. If you don't find it, the patient may come back in shock.
·A high BUN-to-creatinine ratio (above 36) means old blood sat in the small intestine long enough for protein to be absorbed — the source is higher up in the GI tract, not the colon. A true lower GI bleed from the colon does not cause this. Always check the labs and adjust your diagnosis when they don't fit the story.

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