GI Emergencies

• Audio chapter
  Single-voice audio, listen on the commute.
• ABIM-format MCQs
  5-option vignettes with full wrong-answer teaching.
• Study guide
  Tables, decision trees, primary sources.
• AI tutor
  Chapter-grounded, answers the question you're stuck on.

What this chapter covers

• Section 31.1: Massive UGIB resuscitation

  Massive upper GI bleeding is a resuscitation problem before it is an endoscopic problem, and the early decisions that drive outcome happen in the first hour: airway protection, restrictive transfusion, massive transfusion protocol activation if hemorrhage is ongoing, agent-specific anticoagulation reversal, and prokinetic preparation for endoscopy.

• Section 31.2: Acute LGIB management

  Acute lower GI bleeding is hematochezia or hemodynamically significant melena from a source distal to the ligament of Treitz, and the workup branches sharply on hemodynamic stability rather than on the suspected etiology.

• Section 31.3: Acute mesenteric ischemia

  Acute mesenteric ischemia carries mortality of approximately 50 to 80 percent and has held this high mortality despite advances in imaging, because the clinical presentation is non-specific, bowel infarction occurs within hours of vascular compromise, and the diagnostic instinct is often the wrong one (the patient with severe abdominal pain and a soft abdomen looks like a non-emergent presentation until the lactate rises or the bowel infarcts).

• Section 31.4: Foreign body and food bolus impaction

  Foreign body and food bolus impaction is tested through the ASGE timing categories, which map injury risk to a removal window, plus a small set of high-yield special cases (disc batteries, sharp objects, magnets, body packers, food bolus as the EoE gateway).

• Section 31.5: Caustic ingestion and Zargar grading

  Caustic ingestion is a medical emergency in which the substance category drives the injury pattern, the airway is the first priority, the Zargar grade at endoscopy drives short-term management, and the late-stricture and squamous cell carcinoma risks drive long-term surveillance.

• Section 31.6: Esophageal perforation and Boerhaave

  Esophageal perforation can be spontaneous (Boerhaave syndrome from forceful vomiting), iatrogenic (post-endoscopic dilation, post-pneumatic dilation for achalasia, post-EGD with stricture biopsy, post-EMR or ESD), traumatic, or from caustic injury or foreign body.

• Section 31.7: Acute colonic pseudo-obstruction (Ogilvie)

  Acute colonic pseudo-obstruction (ACPO, Ogilvie syndrome) is acute massive colonic dilation without mechanical obstruction in a hospitalized patient, and it is managed as a four-step ladder (rule out mechanical obstruction, support, neostigmine, colonoscopic decompression) anchored by a cecal-diameter and duration threshold that triggers escalation.

Podcast episodes

1. 01

   Massive Upper GI Bleeding Resuscitation

   Episode one of the GI Emergencies chapter treats massive upper GI bleeding as a resuscitation problem before it is an endoscopic one. The organizing idea is a clock that starts when the patient arrives, where permissive hypotension protects the clot and the wrong decision made confidently is worse than none. It moves through the timeline the patient is actually on: restrictive transfusion, the balanced massive transfusion ratio and the calcium citrate chelates, anticoagulation reversal run in parallel rather than as a delay, and field-clearing erythromycin before endoscopy. It closes on the two recognition stems the boards reward, the herald bleed of an aortoenteric fistula and the two arteries where failed hemostasis sends you to interventional radiology.

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2. 02

   Lower GI Bleeding and Mesenteric Ischemia

   Episode two moves below the ligament of Treitz and then to the mesenteric vessels, carrying the same rule forward: pick the imaging that feeds the next intervention and recognize the pattern that flips the algorithm. Acute lower GI bleeding branches on hemodynamic stability, CT angiography for the unstable patient because it hands interventional radiology the anatomy and colonoscopy at twelve to twenty-four hours for the stable one, with the etiologies read by pattern. Colon ischemia separates from diverticular bleeding on pain before bleeding, and isolated right colon ischemia flips the workup toward mesenteric imaging. Acute mesenteric ischemia turns on recognizing pain out of proportion to exam and reaching for CT angiography before lactate rises, then matching intervention to each of four etiologies.

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3. 03

   Foreign Body and Caustic Ingestion

   Episode three works two mechanical emergencies that each hand you a recognition cue and a defined intervention with a clock embedded in it. For foreign bodies the urgency of removal follows the mechanism of injury, not the politeness of the object, sorting into three timing tiers from two-hour disc batteries to blunt objects that never come out. The food bolus doubles as the eosinophilic esophagitis biopsy opportunity that closes if you do not take it at the same procedure. For caustic ingestion, substance category drives the injury pattern, the airway is the first priority, and the Zargar grade at endoscopy drives short-term feeding and monitoring while late stricture and squamous cell carcinoma risk drive long-term surveillance.

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4. 04

   Esophageal Perforation and Ogilvie Syndrome

   Episode four closes the chapter with two emergencies that run on the same cue-plus-threshold-plus-intervention shape, where the threshold is a mechanism in disguise. For esophageal perforation the clock starts when the wall tears, and the twenty-four hour window separates clean primary closure from sealed stent and drainage because the mediastinal tissue planes change from friend to enemy. For acute colonic pseudo-obstruction the clock starts when the colon stops moving, and a four-step algorithm anchored by a cecal-diameter threshold and a neostigmine-with-cardiac-monitoring decision moves the patient from the conservative bundle to pharmacology to decompression to surgery. Laplace's law explains why the cecum fails first and the neostigmine contraindication list explains why every dose comes with atropine at the bedside.

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Key topics

• ·Upper GI bleeding as a resuscitation problem
• ·Restrictive transfusion target and its exceptions
• ·Massive transfusion protocol and calcium repletion
• ·Anticoagulation reversal in the first hour
• ·Pre-endoscopic erythromycin and why TXA fails
• ·Airway protection and endoscopy timing
• ·Aortoenteric fistula recognition
• ·Salvage angiography for failed hemostasis
• ·Acute lower GI bleeding and the BUN-to-creatinine clue
• ·Hemodynamic split: CT angiography versus colonoscopy
• ·Diverticular, angiodysplastic, and post-polypectomy bleeding
• ·Endoscopic hemostasis and the no-serosa rule
• ·Colon ischemia and pain before bleeding
• ·Isolated right colon ischemia flipping the algorithm
• ·Four etiologies of acute mesenteric ischemia
• ·Etiology-specific intervention
• ·The lactate trap and initial bundle
• ·Urgency follows mechanism, not the object
• ·Three timing tiers for removal
• ·Disc batteries, sharps, and magnets
• ·Drug packers versus stuffers
• ·Food bolus and the eosinophilic esophagitis gateway
• ·Alkali versus acid injury patterns
• ·Airway priority and contraindicated interventions
• ·Zargar grading and feeding safety
• ·Late strictures and cancer surveillance
• ·Causes of esophageal perforation and Boerhaave
• ·The Mackler triad and recognition stem
• ·Perforation site and left-sided effusion
• ·Water-soluble contrast imaging and antibiotics