Pediatric Abdominal Pain

EM Cases Classics: Pediatric Abdominal Pain and Appendicitis

In Medical Concepts by Anton Helman1 Comment

Our latest collaboration will see the publication of classic episodes of Emergency Medicine Cases published on CanadiEM. Emergency Medicine Cases is an exceptional podcast developed by fellow Canadian emergency physician, Dr. Anton Helman. In the second episode of Emergency Medicine Cases Classics on CanadiEM, Anton discusses pediatric abdominal pain and appendicitis. -CanadiEM Editor Brent Thoma

Pediatric abdominal pain can be an extremely challenging presentation. Children are not able to provide us with as clear of a history as most adults, we see them less often, and there are many causes that are not common in the adult population. In this blog post we review the content of the podcast which covers a general approach to pediatric abdominal pain and delves in more depth into appendicitis. Expert commentary on the pearls of the history, physical exam, lab tests, imaging, clinical decision rules, analgesics and antibiotics is provided by:

  • Dr. Anna Jarvis, “the mother of pediatric emergency medicine” and a pediatric emergency physician at Sick Kids in Toronto
  • Dr. Stephen Freedman, one of the world’s pre-eminent pediatric emergency medicine researchers and a pediatric emergency physician at the Alberta Children’s Hospital in Calgary.

For more on this topic download the podcastdownload the PDF summary, or add Emergency Medicine Cases to your podcast app and listen to Episode 19.

Common causes of Pediatric Abdominal Pain

The prevalence of various causes of abdominal pain vary with age, but some of the most common include: Gastroenteritis, respiratory tract infections (including otitis media, pharyngitis, and pneumonia), urinary tract infections, constipation, and appendicitis. Appendicitis is missed between 6.9 and 27.6% of the time on initial presentation with ‘gastroenteritis’ being a common mimic [cite num=”1″].

Working up pediatric abdominal pain: Tips from the experts

The physical exam

The physical exam of a child’s abdomen is difficult, but there are some tips that will increase your yield. Our experts had multiple tips for getting the best exam possible:

  • To keep the child calm, allow them to stay in their caregiver’s lap or lying on top of them. Taking them away from their caregiver is likely to upset them and it is very difficult to examine the abdomen of a crying child. If they child is older, they might be willing to palpate their own abdomen.
  • Similarly, allowing them to keep their clothes on initially can help them to stay calm.
  • As discussed in medical school, be sure to percuss before you palpate!
  • You can test for respiratory splinting with the lowering of the diaphragm by asking the child to “blow out candles.”
  • Rebound tenderness can be assessed well in older children by allowing them to jump on the bed and in infants / toddlers by having the caregiver bounce them on their knee.
  • Boys with abdominal pain need to have their testicles examined for possible torsion.

Laboratory tests

Laboratory tests can be sometimes helpful in pediatric patients with abdominal pain. However, they must be interpreted with caution.

  • WBC: About 1/4 of children with gastro will have an elevated WBC because dehydration and acidosis elevate the WBC. Many children with appendicitis will have a normal WBC.  If the appendix is perforated, the vast majority of children will have an elevated WBC count. The bottom line is that it can’t rule these diagnoses in or out.
  • CRP: CRP is likely more sensitive than the WBC in identifying a perforated appendix. However, a normal CRP does not rule it out.
  • Urinalysis (clean catch or catheter specimen): U/A can be useful to rule out DKA, UTI, and pregnancy as causes for abdominal pain. Remember that sterile pyuria Can be consistent with appendicitis and gastro.
  • Chem strip: A ‘finger poke’ to get a glucose level may be useful to rule out hypoglycaemia in severe gastroenteritis as well as hyperglycemia in DKA.

Treating pediatric abdominal pain

Children are generally undertreated for pain in the ED, especially relative to adults. Historically there has been a myth that treating pain will alter clinical decision making and exam findings. However, there is good evidence from multiple studies that administration of appropriate analgesics does not change clinical decision‐making in abdominal pain (or appendicitis) [cite num=”2″][cite num=”3″][cite num=”4″] and may help the ultrasound technicians obtain a more accurate scan. Be sure to provide adequate analgesia to your pediatric patients! Morphine (0.1mg/kg (max 5mg)), Fentanyl (1‐2micrograms/kg), and Ketorolac (0.5‐1mg/kg) are often viable options for pediatric abdominal pain. Codeine has an unpredictable clinical benefit due to genetic variations in how it is metabolized [cite num=”5″]. As a result, it has been removed from some pediatric emergency department formularies and is not recommended.

Additionally, anxiolytic medications such as intranasal midazolam can be helpful in calming selected patients prior to imaging.

Pediatric Appendicitis

The presentation

Appendicitis in pediatrics can be a difficult diagnosis to make because of how variably it presents. Most children less than 4 years old present with perforated appendixes for this reason. They are unable to provide a classic history of periumbilical pain radiating to the right lower quadrant and often do not present with classical anorexia / fever / emesis. In general, the ‘atypical is typical’ in pediatric appendicitis: diarrhea, constipation, and dysuria can lead clinicians astray. The pain may localize to the back because many children have retrocecal appendixes. Patients with perforated appendixes are more likely to have diarrhea and a higher temperature. They are less able to localize their peritoniteal pain.

Imaging

There is huge practice variation when it comes to how to image (or not) children with suspected appendicitis. For children with a very high pre-test probability, some surgeons would perform appendectomy without requiring imaging. Making this decision attempts to balance the negative appendectomy rate in those who do not have imaging-proven appendicitis with the higher perforation rate in those who get imaging due to the delay to the OR.

Ultrasound is widely considered the first-line test due to its lack of radiation and high sensitivity / specificity, but it is limited by technician and radiologist skill, patient cooperation, patient girth (more difficult in obese patients), and the adequacy of anxiolysis and analgesia. Criteria for a positive scan include a tender and non-compressible >6mm appendix, hyperemic appendix, wall thickness >1.7mm, thickening of mesenteric fat, free fluid, increased echogenicity, enlarged lymph nodes, and abscesses. In patients with low pre-test probability, appendicitis can often be confidently excluded even if the appendix is not seen if there are no secondary signs.

If ultrasound is equivocal and clinical suspicion is high, options include surgical consultation, repeat physical exams, repeat blood work, repeat ultrasound (a repeat in 12 hours improves accuracy), or abdominal CT. The lifetime cancer risk of abdominal CT in children is about 1/1000 with young children being most at risk [cite num=”6″].

Decision rules

There is evidence that the use of pediatric appendicitis decision rules can decrease the use of CT scans by about 20%. While their sensitivity has been lower when they have been prospectively validated [cite num=”7″][cite num=”8″], they are most useful in guiding clinicians who do not see pediatric patients on a regular basis.

The two most common instruments are outlined below. Their cutoff values for positive results are somewhat controversial and vary from study to study and for imaging / consultation / diagnosis:

Alvarado Score: 1 point each for ‐ migration of pain to RLQ, anorexia, nausea/vomiting, tenderness in RLQ, rebound pain, fever, leukocytosis, left shift

and the:

Samuel Score or Pediatric Appendicitis Score: 1 point each for – RLQ tenderness elicited by cough, hopping or percussion, anorexia, fever, nausea/vomiting, tenderness over the right iliac fossa, leucocytosis, left shit, migration of pain

Treatment

Any  child  with  sepsis,  peritonitis,  perforated  appendix,  abscessed  appendix  requires  broad  spectrum antibiotics in the emergency department as soon as possible. Those with non‐perforated appendicitis are given antibiotics pre‐operatively to decrease the incidence of wound infection and abscess formation. Patients with perforated appendicitis are usually managed conservatively with antibiotics, percutaneous drainage, and interval surgery (surgery after 8‐12wks). There is some discussion in the literature of treating appendicitis with antibiotics alone, however, this is preliminary and such a decision should likely be made by the surgical service [cite num=”9″].

Conclusion

Pediatric abdominal pain is a difficult presentation to work up. Most children have benign causes, but it is important to recognize the many faces that more severe diagnoses such as pediatric appendicitis can present.

References

  1. Galai T, Beloosesky OZ, Scolnik D, Rimon A, Glatstein M. Misdiagnosis of Acute Appendicitis in Children Attending the Emergency Department: The Experience of a Large, Tertiary Care Pediatric Hospital. Eur J Pediatr Surg. 2016 . PMID: 26745519
  2. Kim MK, Strait RT, Sato TT, Hennes HM. A randomized clinical trial of analgesia in children with acute abdominal pain. Acad Emerg Med. 2002; 9(4): 281-7. PMID: 11927450
  3. Mahadevan M, Graff L. Prospective randomized study of analgesic use for ED patients with right lower quadrant abdominal pain. Am J Emerg Med. 2000; 18(7): 753-6. PMID: 11103723
  4. Kokki H, Lintula H, Vanamo K, Heiskanen M, Eskelinen M. Oxycodone vs placebo in children with undifferentiated abdominal pain: a randomized, double-blind clinical trial of the effect of analgesia on diagnostic accuracy. Arch Pediatr Adolesc Med. 2005; 159(4): 320-5. PMID: 15809382
  5. Madadi P, Koren G. Pharmacogenetic insights into codeine analgesia: implications to pediatric codeine use. Pharmacogenomics. 2008; 9(9): 1267-84. PMID: 18781855
  6. Brenner D, Elliston C, Hall E, Berdon W. Estimated risks of radiation-induced fatal cancer from pediatric CT. AJR Am J Roentgenol. 2001; 176(2): 289-96. PMID: 11159059
  7. Pogorelić Z, Rak S, Mrklić I, Jurić I. Prospective validation of Alvarado score and Pediatric Appendicitis Score for the diagnosis of acute appendicitis in children. Pediatr Emerg Care. 2015; 31(3): 164-8. PMID: 25706925
  8. Wu HP, Yang WC, Wu KH, Chen CY, Fu YC. Diagnosing appendicitis at different time points in children with right lower quadrant pain: comparison between Pediatric Appendicitis Score and the Alvarado score. World J Surg. 2012; 36(1): 216-21. PMID: 22009520
  9. Svensson JF, Patkova B, Almström M, et al. Nonoperative treatment with antibiotics versus surgery for acute nonperforated appendicitis in children: a pilot randomized controlled trial. Ann Surg. 2015; 261(1): 67-71. PMID: 25072441

This blog post was written by Dr. Anton Helman. It was edited for the CanadiEM blog by Dr. Brent Thoma in March, 2016.

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Anton Helman
Anton is an emergency physician at North York General, an Assistant Professor at the University of Toronto, and the Education Innovation Lead at the Schwartz-Reisman Emergency Medicine Institute. He is also the founder and host of Emergency Medicine Cases.
Anton Helman
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