Analgesia for Children with Acute Abdominal Pain in the Emergency Department

One of the most common complaints in the pediatric emergency department is acute abdominal pain and 15% of school aged children are brought to a physician with a chief complaint of abdominal pain [1]. Appendicitis is a common, serious pediatric abdominal emergency and is diagnosed in 7% of children during their lifetime [2,3]. In the past, recommendations were to suspend analgesia in children suspected of having surgical emergencies in order to avoid masking physical signs prior to surgical evaluation [4,5]. These recommendations had been recently challenged and current evidence does not support withholding analgesia in these children. This review discusses the effects of opioid analgesia administration on children with acute abdominal pain on the pain relief, and on the diagnostic accuracy of their illness. MeSH Words: Opioids, Children; Abdominal Pain, Emergency Department Pharmacologic Analgesia Pain is an important symptom that deserves treatment in order to relieve suffering. There is current evidence that treatment with opioid analgesia affects pain perception in children [49]. Green and colleagues [6] demonstrated a clinical, statistically significant difference in pain perception between children treated with opioid analgesia compared to placebo in children 5-16 years old who presented to the emergency department with a chief complaint of acute abdominal pain. Pain was assessed with a color analog scale before and after study medication administration in this double-blind, placebocontrolled trial. In another prospective randomized double blind placebo controlled trial [7], 104 children were randomized to receive either buccal oxycodone or normal saline, and the pain assessment was made by a visual analog scale. Pain relief was significantly better in the oxycodone group (mean difference 13 cm), even though the placebo effect was also significant compared to baseline at 30 minutes after administration. At Analgesia for Acute Peds Abdominal Pain Israeli Journal of Emergency Medicine – Vol. 6, No. 3 Sept. 2006 הפוחד האופרל ילארשיה תעה בתכ 54 60 minutes, oxycodone performed significantly better than placebo which is consistent with pharmacokinetics of buccal oxycodone. [8] In our group's previous study [9], we retrospectively collected data on children 0-16 years old and information on analgesia administration in the pediatric ED, and the physician’s suspected probability of appendicitis. Analgesia was given significantly more often to children with high probability of appendicitis, yet only in half of the cases, and only 15 % received opioids. Safety of opioids for acute abdominal pain The adverse events associated with opioids in acute abdominal pain merits further investigation. In a study by Koki et al. [7], there were only two adverse events to buccal oxycodone (one child had a headache and one had urticaria) but the sample size was small (32 children). Porter et al. [11] studied analgesic efficacy and the incidence of clinically significant adverse drug reaction in 110 pediatric patients receiving continuous intravenous morphine infusions for acute postoperative pain [10]. The most common adverse drug reactions associated with morphine infusions were inadequate analgesia in the first 24 hours (65.5%) and nausea/vomiting (42.5%). There were no cases of respiratory depression (CI= 03.3). Other adverse reactions included urinary retention (13.5%), pruritus (12.7%), dysphoria (7.3%), hypoxemia (4.5%), and difficulty in arousal (0.9%). Discontinuation of the morphine treatment for adverse drug reaction was recorded in 3.6% of the children [10]. We are unaware of any multicenter trial with a very large sample size that has evaluated the adverse outcomes of patient who receive opioids for acute abdominal pain. However, a significant body of evidence exists on the lack of addiction to morphine. Among more than 11,000 patients from Boston, given narcotics during a hospital stay, only 4 had developed an opioid dependence providing sufficient evidence on lack of addiction to morphine [11]. Diagnostic accuracy after opioid administration Green and colleagues [6] examined whether early treatment with analgesia would result in missed diagnosis, delayed treatment or increase diverse outcomes (such as: laparotomy, admission for observation, discharge home) in children presenting to the ED with acute abdominal pain. Early administration of opioids resulted in no difference in detection of appendicitis when compared with placebo, nor did children treated with opioid analgesia differ in their outcomes after surgery. These results challenge the long held assumptions of some pediatric surgeons that analgesia will significantly mask crucial symptoms associated with acute abdominal pain. Koki’s trial [7] showed that early administration of buccal oxycodone did not adversely alter the clinical signs or obscure the surgical diagnosis, although the study was not powered to detect differences in sensitivity, specificity or diagnostic accuracy between the two treatment arms. Adequately powered studies are needed to examine the affects of analgesia on clinical outcomes in children with acute abdominal pain. In a randomized double blind placebo controlled trial among 60 children aged 5-18 years old, administration of morphine did not change the areas of tenderness. There was no significant change in the diagnostic accuracy between the study groups. All patients requiring laparotomy were identified and no significant complications were noted in the morphine group [4].