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.

History

• 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

Investigations

• 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

Women

Do NOT Miss Dx in Acute Pelvic Pain in Women

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

Children

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

Elderly

• 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