Appendicitis

Key Features

Essentials of Diagnosis

• Fever

• Periumbilical abdominal pain

• Anorexia, vomiting, constipation, and diarrhea

General Considerations

• Most common indication for emergency abdominal surgery in childhood

• Frequency increases with age and peaks between 15 and 30 years

• Causes

  • Idiopathic

  • Obstruction of the appendix by fecalith is common predisposing factor

  • Parasites may rarely cause obstruction (especially ascarids)

• Incidence of perforation is high in childhood (40%), especially in children younger than 2 years, in whom pain is often poorly localized and symptoms nonspecific

• To avoid delay in diagnosis, perform a thorough initial physical examination with sequential examinations at frequent intervals over several hours to correctly interpret the evolving symptoms and signs

Clinical Findings

Symptoms and Signs

• Fever

• Periumbilical abdominal pain, which then localizes to the right lower quadrant with signs of peritoneal irritation

• Anorexia, vomiting (follows onset of pain; often bilious), constipation, and diarrhea

• Clinical picture is frequently atypical, especially in young children and infants

• Rectal examination may clarify the site of tenderness or reveal a localized appendiceal mass

Differential Diagnosis

• Pneumonia

• Pleural effusion

• Urinary tract infection

• Right-sided kidney stone

• Cholecystitis

• Perihepatitis

• Pelvic inflammatory disease

• Acute gastroenteritis with Yersinia enterocolitica may present as pseudoappendicitis in 17% of cases

• Other medical and surgical conditions causing acute abdomen

Diagnosis

Laboratory Findings

• White blood cell count is seldom higher than 15,000/μL

• Pyuria, fecal leukocytes, and guaiac-positive stool are sometimes present

• Combination of elevated C-reactive protein (CRP) and leukocytosis

  • Have positive predictive value of 92%

  • However, normal values do not exclude the diagnosis

• Levels of interleukin 6 (IL-6)

  • Show promise as a potential biomarker

  • Usually peaks within 24 hours of onset of pain

Imaging

• A radio-opaque fecalith is present in two-thirds of cases of ruptured appendix

• Ultrasonography shows a noncompressible, thickened appendix in 93% of cases

• Abdominal CT after rectal instillation of contrast may be diagnostic

• An otherwise normal abdominal CT scan with a nonvisualized appendix has been reported to have a negative predictive value of 99%

Treatment

• Exploratory laparotomy or laparoscopy is indicated when the diagnosis of acute appendicitis cannot be ruled out after a period of close observation

• Postoperative antibiotic therapy is reserved for patients with gangrenous or perforated appendix

Outcome

Prognosis

• Mortality rate is < 1% during childhood, despite the high incidence of perforation

• In uncomplicated nonruptured appendicitis, a laparoscopic approach is associated with a shortened hospital stay

References