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

  • In pregnancy, pain in the lower right quadrant, periumbilical area, or right subcostal area due to displacement of the appendix by the uterus

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

DIAGNOSIS

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

TREATMENT

Medications

• 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

Surgery

• Surgical appendectomy in ...