Diagnosing appendicitis in children is very difficulty. Thirty years ago, before we had ultrasound scans and CT scans, the standard textbook advice was—if the doctor did not think that acute appendicitis was likely, he should wait on doing surgery to remove the appendix and recheck the child in 4 to 6 hours and re-examine the patient.
Even today a recent online medical article states that “Appendicitis is a clinical diagnosis with imaging used to confirm equivocal cases.”(1)
However, the symptoms of acute appendicitis in children can be very vague. We diagnose acute appendicitis with at least some of the following signs: fever, Rovsing’s sign, decreased bowel sounds, rebound tenderness, migration of pain from around the umbilicus to the right lower quadrant, guarding of the abdomen, gradual onset of pain, anorexia (decreased appetite), maximal pain in the right lower quadrant, and percussion tenderness.
However, a study showed that 44% of patients diagnosed with acute appendicitis lacked six or more of the above signs (there are ten signs on the above list). (2)
And the problem with waiting until the diagnosis of acute appendicitis is very likely on clinical examination is that the patient may be very sick by the time you can diagnose it clinically.
And the longer a child has acute appendicitis, the more likely are complications such as perforated appendicitis.
A perforated appendix can cause an abscess in the abdoman or even infection throughout the lining of the abdoman (peritonitis). Perforation can lead to a longer hospital stay, the need for IV antibiotics, and (rarely) to death.
So we want to diagnose acute appendicitis as soon as we can to try to get the appendix removed before it has perforated, if possible.
But again that is not always possible because the symptoms of acute appendicitis are often so vague. The child may not appear sick enough to the parents to go to the Emergency Department until the appendix has perforated. That is why the rate of perforation is from 80% to 100% in children less than 3 years old. Overall, 20 to 35% of appendicitis patients have perforation at the time of diagnosis. (3)
But even when the appendix has perforated, the vast majority of children do well.
In the office or the emergency department, the doctor may order a complete blood count, metabolic profile, a urinalysis. In a girl who has entered puberty, the doctor will order pregnancy test.
And an imaging test of the abdomen may be indicated. And this will usually be an ultrasound of the appendix or a CT scan of the abdomen. Each test has strengths and weaknesses and the doctor will order the one that is best for your child (based on all the information the doctor has).
(1) Pediatric Appendicitis, updated 20ll at http://emedicine.medscape.com/article/926795-overview.
(2) Becker T, Kharbanda A, Bachur R. Atypical clinical features of pediatric appendicitis. Acad Emerg Med. Feb 2007;14(2):124-9.
(3) Pediatric Appendicitis, updated 2011 at http://emedicine.medscape.com/article/926795-overview#aw2aab6b2b6aa .
(4) Appendicitis Imaging, updated 2011 at http://emedicine.medscape.com/article/363818-overview .