Epidemiology:
Appendicitis is the most common acute surgical condition in children. Approximately 70,000 children are affected each year in the United States. The peak incidence of appendicitis in children is between ages 12-18. Boys are affected more often than girls. Mortality is low, but morbidity is high in association with perforated appendicitis. Perforation is present in 20-35% of children with increasing frequency in younger children, approaching 100% in infants.
Pathophysiology:
Appendicitis is thought to be due to obstruction of the appendiceal lumen with fecaliths, ingested foreign bodies, parasites, tumors, and/or lymphoid hyperplasia. This obstruction eventually leads to increased intraluminal pressure which causes lymphatic and venous congestion, impaired arterial perfusion, and finally ischemia and necrosis of the appendix leading to perforation.
Typical Presentation:
The child initially presents with malaise and anorexia that may quickly progress to abdominal pain and vomiting. The abdominal pain is initially unrelated to activity, colicky, and periumbilical in location due to visceral inflammation. Over 12-24 hours, the pain becomes somatic, localizing to the right lower quadrant of the abdomen. Somatic pain is usually worsening with movement and is accompanied by anorexia. Nausea and vomiting usually follow the abdominal pain. Fever is usually low-grade with mild tachycardia. Less then 50% of children will have a classic presentation of appendicitis, despite having appendicitis. If diagnosis is delayed beyond 48 hours, perforation rate exceeds 65%. After perforation, the child typically has less abdominal pain and acute symptoms, but eventually develops signs of sepsis and/or small bowel obstruction.
Physical Exam:
First make the child quiet, relaxed, and distracted. Observe the child for signs of fatigue or somnolence. Then gently palpate away from the area of pain. Percuss the abdomen. A small dose of narcotics to make the child more comfortable without changing the exam may be administered.
McBurney’s Point: Tenderness on palpation at 1/3 distance between the umbilicus and the right anterior superior iliac spine.
Rovsing Sign: Right lower quadrant pain with left lower quadrant palpation is a sign of referred pain from appendicitis as the innervation of the intestine does not localize well
Psoas sign: Right lower quadrant pain with external rotation of the right thigh indicates appendicitis or psoas abscess and may indicate that the appendix is retrocecal in location as the iliopsoas muscle is retroperitoneal
Obturator sign: Right lower quadrant pain with internal rotation of the flexed right thigh indicates irritation of the obturator internus muscle which is another indicator of appendicitis.
These signs may not present in children.
Radiography/Labs:
A CBC may initially show a normal leukocyte count but will eventually progress to leukocytosis with a left shift. Urinalysis is abnormal in 10-25% with WBC and or RBC’s without bacteria. About forty percent of pediatric appendicitis can be diagnosed after physical exam and labs with no further workup.
Ultrasound is often first line in evaluation of appendicitis and has a 85% sensitivity and 94% specificity. The appendix usually has a target appearance, has a diameter > 6mm and is non-compressible. A normal appendix must be visualized in order to rule out appendicitis by ultrasound. CT scan is more accurate with 95% sensitivity and specificity, but not used commonly in children due to radiation exposure. Its use is limited to patients in whom the diagnosis is not made by clinical exam/labs or US. Ct can be most useful in obese children and in children suspected of long-standing perforation in whom the presence of an abscess is suspected. A distended, thick-walled appendix, inflammatory streaking of surrounding mesenteric fat, and/or an abscess are all signs concerning for appendicitis or a ruptured appendix.
Pediatric surgeons found to be about 95% accurate using exam, labs, and selective observation with repeat exam and labs.
Differential Diagnosis:
The differential diagnosis of appendicitis in children includes intussusception, Meckel’s diverticulum, gastroenteritis, constipation, mesenteric adenitis, pyelonephritis, nephrolithiasis, pelvic inflammatory disease, ectopic pregnancy, typhlitis.
Treatment:
Traditional treatment of non-perforated appendicitis consists of appendectomy and perioperative antibiotics that cover skin and colonic flora, such as Cefoxitin or Piperacillin/Tazobactam. There is early data to suggest that many patients may be successfully treated with antibiotics alone though this is not considered standard treatment at this time.
In the case of frank peritonitis, surgical exploration and aggressive irrigation should be performed. In the case of perforated appendicitis with a mature abscess cavity, IR drainage and IV antibiotics with or without delayed interval appendectomy is debated, but commonly employed.
Laparoscopic Appendectomy (LA):
Following trans-umbilical port placement, two additional 3-5 mm ports are typically placed in the lower abdomen. Single port appendectomy via an umbilical entry has also been described. The patient is rotated slightly to elevate the right side. The appendix is identified by following the taeniae of the cecum to its base. The appendix is grasped. A window at the base of the mesentery is created. The appendiceal artery and the base of the appendix are ligated and divided. A number of strategies can be used including cautery, endo-loops, Harmonic, etc. The appendix is then placed in a specimen bag and removed through the umbilical port wound. Hemostasis is then confirmed.
Postoperatively, patients are offered a diet if the appendix was not perforated along with perioperative pain medications. In cases of perforated appendicitis, the American Pediatric Surgical Association recommends a minimum of five days of intravenous antibiotics. Average hospital stay in children undergoing laparoscopic appendectomy is 1.6 days.
Laparoscopic Versus Open Appendectomy (OA):
Advantages of laparoscopic appendectomy are a shorter hospital stay (LA: 1.6 days, OA: 2.0 days), less conspicuous incision sites, and a chance to perform diagnostic laparoscopy should the patient be found not to have appendicitis.
There are no significant reported differences in postoperative complications between open and laparoscopic appendectomy, including similar rates of intra-abdominal abscess, stitch abscess, wound infection and small bowel obstruction.
