Appendicitis: Pathogenesis and Clinical Findings
Authors: Yan Yu Wayne Rosen* Reviewers: Wendy Yao Laura Craig Noriyah AlAwadhi* * MD at time of publication
Dull, crampy, diffuse peri- umbilical pain
Pt may develop fever, diarrhea, constipation, vomiting or anorexia as inflammation worsens
Focal, intense, persistent RLQ
pain, abdominal guarding and peritoneal signs (i.e. percussion and rebound tenderness
Dx of healthy adults:
• Men > women
• Commonly 10-30 years old,
can present at any age
• Most common cause of acute abdomen (5% prevalence in all ethnicities)
The appendix is anatomically located in the RLQ; appendicitis may be confused with disorders of surrounding structures: Gynecological Diseases
• RuleoutpregnancywithHCG pregnancy test
• Rupturedovariancyst
• Ectopicpregnancy
• Mittelschmerz(mid-cycle
Gastro-intestinal Diseases
• Meckel’sdiverticulum (presents identically to appendicitis; surgically located 2 feet from ileocecal valve; mostly seen in children)
• Diverticulitis(presentsasleft sided appendicitis)
Non-GI Abdominal Issues
• Mesentericadenitisinkids <15: swollen mesenteric lymph nodes • Renalcolic Obstruction of appendiceal lumen (by fecalith, fibrosis, neoplasia, foreign bodies or lymph nodes in kids) Appendix distension and spasms ↑ lumen pressure, ↓ blood flow to appendix Ischemia, tissue necrosis, loss of appendix structural integrity Bacterial invasion of the appendix wall, causing transmural inflammationandnecrosis Stretching of visceral peritoneum, stimulation of autonomic nerves T9-T10 Progression of inflammation over several days (variable length of time) Irritation of parietal peritoneum, stimulation of somaticnerves If appendix not surgically removed Perforation of colon wall, causing peritonitis, abscesses or death Note: Symptoms hugely variable. Only 30% present with classic history. Diagnosis is mostly clinical. Further investigations: CBC: Leukocytosis (due to inflammatory response) CT: Gold standard test. Thickened visceral membrane with enhancing (white) rim due to ↑ blood flow Legend: Pathophysiology Mechanism Sign/Symptom/Lab Finding Complications Re-Published July 27, 2019 on