Abdominal Pain

  1. Given a patient with abdominal pain, paying particular attention to its location and chronicity:
    1. Distinguish between acute and chronic pain.
    2. Generate a complete differential diagnosis (ddx).
    3. Investigate in an appropriate and timely fashion.
  2. In a patient with diagnosed abdominal pain (e.g., gastroesophageal reflux disease, peptic ulcer disease, ulcerative colitis, Crohn’s disease), manage specific pathology appropriately (e.g., with medication, lifestyle modifications).
  3. In a woman with abdominal pain:
    1. Always rule out pregnancy if she is of reproductive age.
    2. Suspect gynecologic etiology for abdominal pain.
    3. Do a pelvic examination, if appropriate.
  4. In a patient with acute abdominal pain, differentiate between a surgical and a non-surgical abdomen.
  5. In specific patient groups (e.g., children, pregnant women, the elderly), include group-specific surgical causes of acute abdominal pain in the ddx.
  6. Given a patient with a life-threatening cause of acute abdominal pain (e.g., a ruptured abdominal aortic aneurysm or a ruptured ectopic pregnancy):
    1. Recognize the life-threatening situation.
    2. Make the diagnosis.
    3. Stabilize the patient.
    4. Promptly refer the patient for definitive treatment.
  7. In a patient with chronic or recurrent abdominal pain:
    1. Ensure adequate follow-up to monitor new or changing symptoms or signs.
    2. Manage symptomatically with medication and lifestyle modification (e.g., for irritable bowel syndrome).
    3. Always consider cancer in a patient at risk.
  8. Given a patient with a diagnosis of inflammatory bowel disease (IBD) recognize an extra intestinal manifestation.

DDx Abdominal Pain

  • Cardiovascular:
    • ACS, pericarditis
    • Aortic dissection, mesenteric ischemia, sickle cell crisis
  • Pulmonary:
  • Biliary:
    • Cholecystitis, cholelithiasis, cholangitis
  • Gastric:
    • Esophagitis, gastritis, peptic ulcer, small-bowel mass or obstruction
  • Colonic:
  • Hepatic:
  • Pancreatic:
  • Renal:
    • Cystitis, nephrolithiasis, pyelonephritis
  • Splenic:
    • Abscess
  • Gynecologic:
    • Ectopic pregnancy, ovarian mass, ovarian torsion, PID, fibroids, endometriosis, ovulatory pain, ruptured ovarian cyst
  • Abdominal wall:
    • Herpes zoster, muscle strain, hernia
  • Metabolic:
    • Uremia, DKA, porphyria, adrenal insufficiency, narcotic withdrawal, heavy metal poisoning
  • Psych:


  • Acute vs. Chronic
  • Fever, stools (diarrhea, bloody), vomiting (bilious, bloody)
  • Malignancy (early satiety, weight loss, night sweats, changes in stools)
  • Alcohol, smoking, drugs
  • NSAIDs
  • Past surgeries (obstruction)
  • Females (pregnancy)
    • Vaginal bleeding/discharge, LMP

Physical Exam

  • Vitals
  • Chest/Lung
  • Abdo
  • Pelvic/Genital exam
  • Rectal exam


  • Labs (eg. CBC, ALT/AST, amylase/lipase, lytes (glucose, creat), UA, bhCG)
  • Ultrasound
  • X-ray (CXR, AXR)
  • Endoscopy/Colonoscopy
  • ERCP
  • Urea breath test

Choice of imaging

  • Ultrasound (gallbladder, gyne) if RUQ/suprapubic
  • Otherwise, CT
    • Consider IV contrast for RLQ, non-localized (r/o appendicitis)
    • Consider Oral + IV contrast LLQ (r/o sigmoid diverticulitis)
  • X-ray limited use
    • Free air (if upright)
      • Perforation
    • Calcifications
      • 10% of gallstones, 90% of kidney stones, and 5% appendicoliths
    • Multiple dilated loops of the bowel and air-fluid levels
      • Bowel obstruction or paralytic ileus


Do NOT Miss Dx in Acute Pelvic Pain in Women

  • Life-threatening
    • Ectopic pregnancy
    • Appendicitis
    • Ruptured ovarian cyst
  • Fertility-threatening
    • PID
    • Ovarian Torsion


Red Flags

  • Fever (after onset of vomiting or pain)
  • Bilious vomiting
  • Bloody diarrhea
  • Absent bowel sounds
  • Voluntary guarding
  • Rigidity
  • Rebound tenderness
  • ** Do not forget testis **

Differential diagnosis based on age group

  • <1yo
    • Common: Colic, constipation, GERD, food protein allergy
    • Urgent: Acute gastroenteritis, malrotation without volvulus, pyloric stenosis
    • Emergent: Trauma (abuse), midgut volvulus, NEC, omphalitis, incarcerated hernia, intussusception
  • 1-5yo
    • Common: UTI, constipation
    • Urgent: Acute gastroenteritis, HSP, pneumonia, Meckel diverticulum
    • Emergent: Trauma, appendicitis, asthma
  • 5-12yo
    • Common: UTI, constipation, functional
    • Urgent: Acute gastroenteritis, IBD, HSP, pneumonia
    • Emergent: Trauma, appendicitis, gonadal torsion, DKA, asthma
  • >12yo
    • Urgent: Gastroenteritis, IBD, pneumonia, hepatitis, pancreatitis, nephrolithiasis, PID
    • Emergent: Trauma, appendicitis, gonadal torsion, ectopic pregnancy, DKA, asthma

Investigation in children with abdominal pain

  • Consider urinalysis, CBC, pregnancy test, ESR/CRP
  • Consider ultrasound prior to proceeding with abdominal CT


  • More likely complicated by coexistent disease, medications
  • May present later in course of illness and nonspecific symptoms
    • Physical examination can be misleadingly benign
  • Increase risk of cholecystitis, pancreatitis, diverticulitis, obstructions (adhesions, malignancy)
  • Do not miss AAA, mesenteric ischemia