Appendicitis affects approximately 75,000 children annually. It is one of the most common causes of acute abdominal pain in pediatrics and the most common indication for emergency abdominal surgery in children.
PATHOGENESIS AND EPIDEMIOLOGY
Appendicitis is classically believed to be secondary to obstruction of the appendiceal orifice, commonly either by a fecalith or lymphoid hyperplasia after viral illness. Other causes of obstruction include parasites and tumors. Obstruction of the vermiform appendix leads to a closed loop, with mucus production, bacterial overgrowth, and resultant distention. The increased luminal content results in increased wall tension, further leading to decreased blood flow, and eventual ischemic and inflammatory necrosis and perforation.
Approximately 7% of the US population is affected by appendicitis, with an incidence of 11 cases per 1000 people per year. The mean age of pediatric appendicitis is 6 to 10 years old, with a slightly more common occurrence in males (male-to-female ratio 3:2).
The lumen of the appendix becomes blocked, distending the appendix, which stretches the visceral peritoneum causing referred pain to the umbilicus, often perceived as vague periumbilical pain. This is often accompanied by anorexia and nausea. As the course progresses and the parietal peritoneum becomes more irritated, the pain localizes in the right lower quadrant midway between the umbilicus and the anterior iliac crest (McBurney’s point). Appendicitis can also be accompanied by emesis, fever, and a myriad of clinical exam findings depending on the location of the appendix (Table 408-1).
TABLE 408-1CLINICAL SIGNS FOR APPENDICITIS AND THEIR EPONYMS ||Download (.pdf) TABLE 408-1CLINICAL SIGNS FOR APPENDICITIS AND THEIR EPONYMS
|Referred pain to the epigastrium when pressure is applied to McBurney’s point
|Increased pain on palpation of the right Petit triangle
|Pain on palpation of right iliac region, when the patient is on the left side compared to when the patient is supine
|Pain in the right lower quadrant with cough
|Presenting history of pain in the periumbilical region with shift to the right iliac region
|Patient grimace after a “swish” of the examiner’s index finger across the abdomen, from the xiphoid process to the right, but not left, iliac fossa
|Pain in the right lower quadrant midway between the umbilicus and the anterior iliac crest
|Pain with internal rotation of the hip
|Right lower quadrant pain with right hip extension
|Right lower quadrant pain induced by palpation of the left lower quadrant
|Area of skin hyperesthesia bounded by the anterior superior iliac spine, pubic tubercle, and umbilicus
|Increased pain in the right iliac region when lying on the left side