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Am Fam Physician. 2001;63(2):343-344

Accurate diagnosis of appendicitis in children remains difficult, and delays in diagnosis lead to increased rates of morbidity and mortality. Rothrock and Pagane reviewed the presentation and evaluation of appendicitis in children.

The appendix is a long, thin diverticulum arising from the inferior tip of the cecum. Appendicitis is precipitated by luminal obstruction or mucosal ulceration with bacterial infection. If surgery is delayed, the appendix perforates, and pus is spilled into the peritoneal cavity, causing peritonitis or abscess formation.

Appendicitis causes acute abdominal pain in up to 8 percent of children who undergo emergency evaluation of such pain. Neonatal and prenatal appendicitis have occurred. Decreased dietary fiber and ingestion of refined carbohydrates are risk factors for appendicitis. A high-fiber diet may speed stool transit time, reduce fecal viscosity and inhibit fecalith formation, decreasing the potential for appendiceal lumen obstruction.

The incidence of appendicitis increases during viral epidemics and outbreaks of amebiasis and bacterial gastroenteritis. Extended breast-feeding seems to significantly decrease the risk of appendicitis, and there appears to be a genetic predisposition for this infection.

Appendicitis pain typically begins as a vague periumbilical discomfort followed by parietal peritoneum inflammation localized to the right lower quadrant. This classic migration of pain does not occur in one third of pediatric cases. The classic location of the appendix, known as McBurney's point, is one third of the distance from the right anterior superior iliac spine to the umbilicus. Nausea and vomiting with fever are common.

In neonates, the clinical features of appendicitis are nonspecific and include irritability or lethargy, abdominal distention, vomiting, a palpable abdominal mass and cellulitis of the abdominal wall. In infants and children up to two years of age, symptoms include vomiting, pain, diarrhea and fever. Diagnosis is more difficult in this age group because the symptoms are nonspecific. In children two to five years of age, symptoms include vomiting, abdominal pain, fever and anorexia. Tenderness of the right lower quadrant is more common in this age group than it is in younger children, who usually have diffuse tenderness. The incidence of appendicitis increases in children six to 12 years of age and in adolescents 13 years or older, with symptoms that include vomiting and abdominal pain that worsens with movement or cough. Tenderness in the right lower quadrant is common.

A white blood cell (WBC) count is nonspecific and insensitive for appendicitis. Serum C-reactive protein, a nonspecific inflammatory mediator, may be useful in serial testing to identify appendiceal infection. The only mandatory laboratory test in patients with suspected appendicitis is a pregnancy test in women of childbearing age. Plain radiographs of the abdomen are useful only if free air, bowel obstruction or a mass is suspected, or if the patient has a history of renal stones or cholelithiasis. Radioisotope-labeled WBC scanning has low sensitivity and specificity and is difficult to interpret accurately. Ultrasonography has good sensitivity for a perforated appendix and helps identify alternate diagnoses. Computed tomographic (CT) scanning has good sensitivity and specificity, especially if fat streaking is noted or if the appendix is greater than 6 mm in diameter. The usefulness of magnetic resonance imaging in the identification of appendicitis is being studied.

The authors conclude that the diagnosis of appendicitis in children may be enhanced by more widespread use of ultrasonography and CT scanning. A knowledge of age-dependent physiology and clinical symptomatology will improve diagnostic accuracy.

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