Appendicitis refers to inflammation of the appendix. The first appendectomy was completed by Claudius Amyand in 1735 when he operated on an 11-year-old male for a strangulated inguinal hernia and discovered the appendix in the hernial sac. The first intentional appendectomy was performed by Lawson Tait in 1880.


  • Luminal obstruction from various etiologies, leading to increased mucus production and bacterial overgrowth, resulting in wall tension and eventually necrosis and potential perforation


  • Vague periumbilical abdominal pain, migrating to RLQ pain over time
  • Anorexia
  • Nausea
  • ± Vomiting
  • ± Diarrhea
  • ± Constipation

Physical Exam

  • Ill-appearing
  • ± Fever
  • Tachycardia
  • Mild dehydration
  • + McBurney’s sign
  • Rebound tenderness
  • Rigidity → if present, points towards perforation
  • ± Rovsing sign
  • ± Obturator sign
  • ± Psoas sign


  • WBC and inflammatory markers lack accuracy for diagnosis
  • Leukocytosis, often with “left shift”


  • CT w IV contrast
    • Most commonly used; effective and accurate; sensitivity 76-100%, specificity 83-100%
    • Findings: thickened, inflamed appendix with surrounding “stranding” indicative of inflammation, > 7 mm in diameter, mural enhancement or “target sign”
  • Xray → lack sensitivity and specificity
  • US
    • May have greater utility in pediatric or pregnant patients
    • Success of study depends greatly on skill of the sonographer
  • MRI w/o contrast
    • Reserved for pregnant patients
    • Criteria for MRI diagnosis: appendiceal enlargement (> 7 mm), thickening (> 2 mm), presence of inflammation
    • Cons: higher cost, motion artifact


  • Appendectomy
  • Fluid resuscitation, as indicated
  • Broad-spectrum IV antibiotics
  • Pain control: opioids, NSAIDs, acetaminophen

Relevant Information

  • Appendix orientation
    • Retrocecal (65%)
    • Pelvic (31%)
    • Subcecal (2.3%)
    • Preileal (1.0%)
    • Retroileal (0.4%)
  • Fold of Treves
    • Bloodless fold; no sizable blood vessels
    • Peritoneal structure that extends from the antimesenteric border of the terminal ileum to the base of the appendix, or anterior surface of the mesoappendix, or both
    • Can aid in the recognition of the ileocecal region and base of the appendix


  • Perforation: can lead to sepsis, increased risk with prolonged duration of symptoms; rigidity will be present upon physical exam

Scoring Systems

  • No signs or symptoms have been shown to be uniquely predictive of appendicitis, so scoring systems have been developed to help with clinical diagnosis
  • Alvarado scoring
    • 8-item clinical and laboratory variables
    • Scoring < 4 useful in excluding appendicitis; higher score lacks specificity
    • Most widely used and acceptable
  • Pediatric Appendicitis Score (PAS)
  • Appendicitis Inflammatory Response Score (AIRS)

Differential Diagnoses

  • Crohn ileitis
  • Mesenteric adenitis
  • Intussusception
  • Meckel diverticulum
  • Ectopic pregnancy
  • Testicular torsion
  • Ovarian torsion
  • Kidney stones
  • Gastroenteritis
  • PID
  • Endometriosis
  • Renal colic
  • Irritable bowel disease