The overall approach to pain in children has come a long way in the last several decades. Not very long ago, it was believed that very young children did not experience pain, and even if they did, there was no memory of it. Thus, pain in young patients was not regularly or assertively treated. We now know that the neural mechanisms that encode pain perception and that shape our responses to pain develop early in life. Pain systems develop and function as early as 23 weeks of gestation.¹

Proper management of pediatric patients with pain is essential as there are consequences of untreated pain in the young. Similar short- and long-term sequelae to adults can occur, such as wind up, hyperalgesia, and allodynia.² In children, tissue damage during certain critical periods of development may have a lasting effect, even into adulthood. In addition, there are behavioral, psychological, and social ramifications of untreated pain in children that can carry on to adulthood and chronic pain conditions.

This chapter does not cover all the details of every pain-causing condition in children and their treatment options. Unique aspects of taking care of pain in this population will be highlighted, along with reminders of when referrals to pediatric specialists should be considered.

As with pain assessment in all patients, the approach to pain assessment in children should be multidimensional, with attention to assessment of functionality. This involves gathering information from a variety of sources: patients (if they are able), parents, and/or caregivers. These reports should focus not just on the facets of the pain or primary pain complaint itself but also on other related areas such as school performance/attendance, social relationships, sleep, and mood disturbances. Direct observation of behavior and physiologic measurements should also be used in the assessment of pediatric patients with pain. If interventions are performed, careful monitoring of responses to therapeutic trials can keep track of progress. This broad approach to assessment allows a natural opportunity to plan and set expectations. Early conversations about goals of therapy and equipping the patient and family with knowledge, assurance, and coping skills will establish a positive relationship for all involved.

There are multiple validated scales for pain measurement in children. If a child is old enough and can understand a self-report scale, this should be the main tool used to measure and keep track of pain over time. Self-reported scales can be the simple 0-10 scale, which is useful in children old enough to understand a numerical scale. The FACES scale is the most commonly used self-reported scale for children who may not be able to reliably use a numerical scale. The scale shows a series of FACES ranging from a happy face at 0, or “no hurt,” to a crying face at 10, which represents “hurts like the worst pain imaginable.” Based on the faces and written descriptions, the child chooses the face that best describes his or her level
of pain. In younger patients unable to use a self-report tool, there are observational scales, such as the FLACC scale. These utilize an observer’s assessment of things such as Facial expression, Leg movement, Activity, Crying, and Consolability. The acronym FLACC facilitates recall of these elements. Age ranges vary for these scales, so it is essential to use clinical judgment regarding appropriateness for pain assessment. Regardless of the scale used to assess a child’s pain, the key is to be as consistent as possible. This includes not only the scale used to assess but also the frequency in which it is assessed, and in what setting.

It is important to briefly note here that as in any assessment of pain causes or sources, the “red flag” list of serious illness processes must be considered. If the child’s young age or presentation prevents a complete consideration by the primary care physician, the child should be referred to a pediatric specialist who can complete the workup to ensure that an undiagnosed major illness is not the source of the patient’s pain.

Approach to nociceptive pain in children does not differ significantly from the approach used in adults. Mild to moderate pain is often treated with oral nonsteroidal anti-inflammatory drugs. Moderate pain may require the addition of an oral opioid. Moderate to severe pain may require the use of intravenous opioids to achieve rapid titration and control of the pain (Table 8-1).

There are some practical concepts when approaching opioid analgesia in children. With severe pain, intravenous administration is often effective quickly. However, each child may respond differently to a given opioid and may have differing respiratory reserve and other complicating medical conditions. Titrating to effect is important in these situations and to give time for a dose to take effect before another dose. This of course, must occur in a proper setting with personnel, monitoring, and support. Oral opioids are not ideal to titrate to effect in these situations because their peak effects may not be seen for hours and repeat oral dosing in a short interval can lead to respiratory depression and other unwanted side effects.

Table 8-2 outlines the opioid options for managing acute pain. There is a notable drug not included in this table. Codeine should not be one of the opioid options used in children. The US Food and Drug Administration placed a black boxed warning on codeine in 2013. Its use is specifically contraindicated in children undergoing adenotonsillectomy with obstructive sleep apnea. This came about after cases of death and serious adverse events in children.³ There was evidence in some of these children that they were ultrafast metabolizers of codeine, a genetic variant of the liver enzyme pathway that turns codeine into its active form, morphine in the body. It is not readily possible to know which patients are ultrafast metabolizers of this drug, and therefore, caution should be used when prescribing this drug or other opioids that are metabolized in a similar manner.

When using medications from Tables 8-1 and 8-2, it is important to note that there are combination drugs with an opioid and acetaminophen or ibuprofen. The maximum daily dose, appropriate for the patient’s age, needs to be adhered to with specific instructions to parents and caregivers about these limits.