I. Gastrointestinal Emergencies

A. Gastrointestinal Bleeding

1. 1. Presentation: Blood loss from the gastrointestinal (GI) tract occurs in four ways: hematemesis, hematochezia, melena, and occult bleeding.
2. 2. Differential diagnosis of GI bleeding: Table 12.1
3. 3. Diagnosis/management:
   1. a. Assess airway, breathing, circulation, and hemodynamic stability.
   2. b. Perform full physical exam and verify bleeding with rectal examination and testing of stool or emesis for occult blood. Notable exam findings include abdominal tenderness, guarding, rebound, hepatosplenomegaly, perianal skin tags, or fissures.
   3. c. Obtain baseline laboratory tests: Complete blood cell count (CBC), coagulation studies, type and screen, reticulocyte count, complete metabolic panel (CMP), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR), and assess for disseminated intravascular coagulation (d dimer, fibrinogen).
   4. d. If concerned for hemodynamic instability, begin initial fluid resuscitation. Consider transfusion if there is continued bleeding, symptomatic anemia, and/or a hematocrit level <21%. Initiate intravenous (IV) proton pump inhibitor (PPI).
   5. e. Further evaluation and therapy based on the assessment and site of bleeding:
      1. (1) Upper GI bleeding: Consider esophagogastroduodenoscopy (EGD) and testing for Helicobacter pylori.¹ Gastric lavage via nasogastric (NG) tube or administration of IV erythromycin may increase visibility and diagnostic yield.^{2, 3}
      2. (2) Lower GI bleeding: Consider abdominal radiograph, upper GI study (± small bowel follow-through), air-contrast barium enema, colonoscopy, Meckel scan, tagged red cell scan, computed tomography (CT), and magnetic resonance enterography (MRE). Consider stool cultures, stool ova and parasites, Clostridium difficile toxin, and stool calprotectin.

B. Acute Abdomen⁴

1. 1. Definition: Severe abdominal pain that may require emergency surgical intervention
2. 2. Differential diagnosis: Table 12.2
3. 3. Diagnosis:
   1. a. History: Course and characterization of the pain, emesis, melena, hematochezia, diet, stool history, fever, travel history, menstrual history, vaginal/testicular symptoms, urinary symptoms, respiratory symptoms, and recent surgeries
   2. b. Physical exam: Rashes, arthritis, and jaundice. Abdominal tenderness on palpation, rebound/guarding, rigidity, masses, distention, or abnormal bowel sounds, rectal examination with stool hemoccult testing, pelvic examination (discharge, masses, adnexal/cervical motion tenderness), and genital examinations
   3. c. Labs: CBC, CMP, coagulation studies, lactate, type and screen, urinalysis, amylase, lipase, gonorrhea/chlamydia testing, β-human chorionic gonadotropin (β-hCG), ESR, and CRP
   4. d. Imaging: Two-view abdominal radiographs to assess for obstruction, constipation, free air, gallstones, and kidney stones. Consider chest radiograph to evaluate for pneumonia, abdominal/pelvic ultrasonography, and abdominal CT with contrast or magnetic resonance imaging (MRI).
4. 4. Management: Ensure patient is NPO and begin IV hydration. Consider nasogastric decompression, serial abdominal examinations, surgical/gynecologic/GI evaluation, pain control, and antibiotics as indicated.