Appendicitis, Acute

• • Abdominal pain

  • Anorexia, nausea, and vomiting

  • Localized right lower quadrant pain

  • Low-grade fever

  • Leukocytosis

Epidemiology

• • 7% of people in Western countries have appendicitis at some time in their lives

  • 200,000 appendectomies for acute appendicitis are performed each year in the United States

  • Incidence in developing countries has been increasing in proportion to economic gains and changes in lifestyle

  • Major causes: Obstruction of the proximal lumen by fibrous bands, lymphoid hyperplasia, fecaliths, calculi, or parasites

  • Evidence of temporal and geographic clustering of cases has suggested a primary infectious etiology

  • Diagnosis is most difficult in the very young or old

  • Highest incidence of false-positives occur in women between the ages of 20 and 40, attributable to pelvic inflammatory disease (PID) and other gynecologic conditions

Symptoms and Signs

• • Classically, abdominal pain develops prior to nausea and vomiting

  • Peri-umbilical abdominal pain initially, then localizes to the right lower quadrant

  • Right lower quadrant rebound or percussion tenderness (localized "peritoneal irritation")

  • Constipation and indigestion are frequent complaints

  • Patients complain of discomfort with movement, walking, or coughing

  • Low-grade fever (99 °F-101 °F) unless perforation has occurred

Laboratory Findings

• • Mild leukocytosis (10,000-15,000) with left shift

  • Mild elevations in amylase

  • UA frequently will show a few WBC and RBCs on microscopic exam

  • Elevated C-reactive protein and ESR levels

Imaging Findings

• • Plain films may show evidence of localized air fluid levels or localized ileus or increased soft-tissue density in the right lower quadrant

  • -Less common findings include an appendiceal calculus, altered right psoas stripe, or an abnormal right flank stripe

  • US may demonstrate a dilated tubular structure in the right lower quadrant although this technique is user- and institutional-dependant and is less sensitive in adults than in children

  • Spiral CT (either abdominal/pelvic or a dedicated "appendiceal protocol") is the most sensitive and specific diagnostic radiographic test

  • -An enlarged appendix with peri-appendiceal fat stranding is demonstrated in 90-95% of cases

    -CT scans are of greatest value in patients with atypical clinical presentation or laboratory findings

• • Acute salpingitis

  • PID

  • Regional enteritis/complicated Crohn disease

  • Viral gastroenterologic infection

  • Mesenteric adenitis

  • Dysmenorrhea

  • Ovarian lesions

  • Urinary tract infections

  • Small bowel obstruction

  • Cecal volvulus

  • Incarcerated hernia

  • Mesenteric ischemia

  • Acute cholecystitis

  • Right-sided diverticulitis (true cecal or a redundant sigmoid that flops over into the right lower quadrant)

  • Complicated peptic ulcer disease (with enteric contents collecting in the right paracolic gutter)

  • Infarcted epiploic appendage

Rule Out

• • Nonsurgical etiology of right lower quadrant abdominal pain

  • -Acute salpingitis

    -Dysmenorrhea

    -Urinary tract infections

    -Viral gastroenterologic infection

    -Mesenteric adenitis

    -Others

  • Complicated appendicitis manifested by right lower quadrant abscess formation

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