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For further information, see CMDT Part 15-30: Appendicitis

Key Features

Essentials of Diagnosis

  • Early: periumbilical pain

  • Later: right lower quadrant pain and tenderness

  • Anorexia, nausea and vomiting, obstipation

  • Tenderness or localized rigidity at McBurney point

  • Low-grade fever

  • Leukocytosis

General Considerations

  • The most common abdominal surgical emergency, affecting ~10% of the population

  • Occurs most commonly between the ages of 10 and 30 years

  • Caused by obstruction of the appendix by a fecalith, inflammation, foreign body, or neoplasm

  • If untreated, gangrene and perforation develop within 36 hours

Clinical Findings

Symptoms and Signs

  • Vague, often colicky, periumbilical or epigastric pain

  • Within 12 hours, pain shifts to right lower quadrant, with steady ache worsened by walking or coughing

  • Nausea and one or two episodes of vomiting in almost all

  • Constipation

  • Low-grade fever (< 38°C)

  • Localized tenderness with guarding in the right lower quadrant

  • Rebound tenderness

  • Psoas sign (pain on passive extension of the right hip)

  • Obturator sign (pain with passive flexion and internal rotation of the right hip)

  • Atypical presentations include

    • Pain less intense and poorly localized; tenderness minimal in the right flank

    • Pain in the lower abdomen, often on the left; urge to urinate or defecate

    • Abdominal tenderness absent, but tenderness on pelvic or rectal examination

    • In older adults, symptoms may be vague, mild abdominal tenderness may be present

Differential Diagnosis

  • Gastroenteritis or colitis

  • Gynecologic

    • Pelvic inflammatory disease

    • Tubo-ovarian abscess

    • Ovarian torsion

    • Ruptured ectopic pregnancy or ovarian cyst

    • Mittelschmerz

    • Endometriosis

  • Urologic

    • Testicular torsion

    • Acute epididymitis

  • Urinary calculus

  • Pyelonephritis

  • Diverticulitis

  • Meckel diverticulitis

  • Carcinoid of the appendix

  • Perforated colon cancer

  • Crohn ileitis

  • Perforated peptic ulcer

  • Cholecystitis

  • Mesenteric adenitis

  • Typhlitis (neutropenic colitis)

  • Mesenteric ischemia


Laboratory Tests

  • Moderate leukocytosis (10,000–20,000/mcL [10–20 × 109/L]) with neutrophilia

  • Microscopic hematuria and pyuria in 25%

Imaging Studies

  • Imaging may be useful in patients in whom the diagnosis is uncertain

  • Imaging studies (ultrasonography or CT) suggest alternative diagnosis in up to 15%

    • Useful in the exclusion of adnexal disease in younger women

  • Abdominal CT

    • Most accurate test for diagnosis (sensitivity 94% and specificity 95%)

    • Useful in suspected appendiceal perforation to diagnose a periappendiceal abscess



  • Preoperative broad-spectrum antibiotics with gram-negative and anaerobic coverage reduce the incidence of postoperative infections

  • Recommended intravenous regimens include

    • Cefoxitin or cefotetan 1–2 g every 8 hours

    • Ampicillin-sulfabactam 3 g every 6 hours

    • Ertapenem 1 g as a single dose


  • Surgical appendectomy in patients with uncomplicated appendicitis; when possible, a laparoscopic approach is preferred to open laparotomy

  • Emergency appendectomy in patients with perforated appendicitis with generalized ...

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