Review Topic
  • A 17-year-old boy is brought to the emergency room by his parents for increasing abdominal pain. He started having periumbilical pain last night but now reports increasing right lower quadrant pain. He reports that about an hour ago, the pain acutely intensified and was not responsive to ibuprofen or acetaminophen anymore. On physical exam, his abdomen is rigid with involuntary guarding and tenderness to light percussion. A right lower quadrant ultrasound shows an enlarged appendix with possible perforation. He is emergently taken to the operating room.
  • Overview
    • acute abdomen is characterized by acute onset of severe abdominal pain that requires urgent surgical evaluation
      • management depends on etiology
  • Epidemiology
    • incidence
    • etiologies
      • hemorrhage
        • abdominal aortic aneurysm rupture
        • bleeding gastric ulcer
        • ruptured ectopic pregnancy
      • ischemia
        • ischemic bowel disease
      • perforated bowel/peritonitis
        • perforated peptic ulcer
        • bowel obstruction
        • diverticular disease
        • inflammatory bowel disease
        • perforated appendicitis
  • Pathogenesis
    • mechanism
      • hemorrhage will often lead to hypovolemic shock, requiring swift intervention
      • ischemia results in elevated lactate and also requires early intervention
      • perforated bowel causes inflammation of the peritoneum or peritonitis
  • Symptoms
    • common symptoms
      • dehydration
      • sudden-onset abdominal pain
      • pain out of proportion to exam
        • ischemic bowel disease
  • Physical exam
    • inspection
      • pallor
      • hypovolemia
      • tachycardia
    • motion
      • rigid abdomen
      • tenderness to percussion
      • involuntary guarding
      • may have reduced or absent bowel sounds
  • Chest radiograph
    • indications
      • to look for free air under the diaphragm
    • findings
      • free air under the diaphragm, indicating bowel perforation
  • Abdominal radiograph
    • indications
      • if bowel obstruction is suspected
    • findings
      • dilated loops of bowel
  • Abdominal ultrasound
    • indications
      • if biliary or hepatic etiology is suspected
      • if tubo-ovarian pathology is suspected
      • if appendicitis is suspected
      • if aneurysm is suspected
      • evaluate for hemorrhage
  • CT abdomen and pelvis
    • indications
      • if mesenteric ischemia, diverticulitis, or bowel perforation are suspected
  • Serum labs
    • lactate
    • arterial blood gas
    • urinalysis
    • pregnancy test 
    • blood cultures
      • to rule out infection
    • amylase and lipase
      • if pancreatitis is suspected
    • complete blood count
    • electrolytes
    • liver function panel
Differential by Location of Abdominal Pain
  • Bowel obstruction
  • Mesenteric ischemia
Right Upper Quadrant Epigastric Left Upper Quadrant
  • Acute cholecystitis
  • Hepatitis
  • Liver abscess
  • Acute cholangitis
  • Peptic ulcer disease
  • Myocardial infarction
  • Pancreatitis
  • Gastric ulcer
  • Splenic rupture
Right Lower Quadrant Periumbilical Left Lower Quadrant
  • Appendicitis
  • Bowel obstruction
  • Appendicitis
  • Abdominal aortic aneurysm
  • Diverticulitis
Lower abdomen
  • Inguinal hernia
  • IBD
  • UTI
  • Pelvic inflammatory disease
  • Ectopic pregnancy
  • Testicular torsion
  • Management approach
    • depends on the etiology of acute abdomen
  • Medical
    • supportive care
      • indications
        • all patients
      • modalities
        • intravenous hydration
        • analgesia
        • anti-emetics
        • nasogastric decompression if necessary
        • bowel rest
        • NPO
        • blood transfusion if necessary
  • Surgical
    • surgical intervention
      • indications
        • irreversible pathologies such as appendicitis, mesenteric ischemia, and perforated bowel
  • Septic shock
  • Death

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