Presence and grade of undertreatment of pain in children with cerebral palsy

Introduction

One of the most common inborn childhood neurological diseases is cerebral palsy (CP) with a prevalence of 1.5–2.7 per 1,000 live births [1]. CP is perceived as a primary movement disorder, but the components of sensory disturbances of pain in children with CP are often unrecognized and thus underappreciated in pain treatment [1], [2], [3]. The occurrence of pain globally has an alarming prevalence of up to 74 percent in the pediatric population with CP and is often more secondary to musculoskeletal complications than it is related to the disease itself (e.g. hip dislocation, musculoskeletal deformity, scoliosis, spasticity) or due to interventions (e.g. surgery, physiotherapy, botulinum toxin injections) [4, 5]. Pain in children with CP has a major impact on the quality of life as it affects activities of daily living and quality of sleep. This can influence mental health negatively [1, 5, 6] and can consequently reduce the quality of life of the parents significantly [7]. Evidently, for these children, there appears to be an urgent need for pain treatment, but as long as the extent and nature of pain and pain treatment are poorly mapped, we are unable to provide children with CP adequate pharmacological and non-pharmacological pain interventions [8], [9], [10].

We sought to investigate how pain in children with CP was treated with the current medical pain treatment and pain coping interventions for everyday pain in our region using the pain management index (PMI). The PMI can be used to describe analgesic interventions and evaluate the adequacy of pain interventions [11], [12], [13]. Cleeland et al. originally developed the PMI to evaluate cancer patient’s worst pain to their prescribed pain medication to determine the adequacy of pain management [12]. Since then, the PMI has been modified to evaluate several other types of pain. We utilized a modified PMI, which evaluated if pain treatment was sufficient when compared to the individual patient’s pain level by a dichotomous score [11, 12]. The PMI score is then calculated by comparing the worst pain intensity, as in the pain at its highest moments of intensity, to pain treatment by subtracting a pain intensity score (0–3) from a treatment ‘analgesic score’ (0–3). A negative value of PMI indicates undertreatment in pain management while zero and positive values indicate adequate pain management [11, 12]. We utilized the modification of Ward et al. by including the pain medication actually used instead of prescribed and most notably also incorporated the least pain intensity (pain at its lowest moments) felt in addition to worst pain intensity (pain at its highest moments) to stratify the adequacy of pain treatment further into a grouped PMI of (1) inadequate pain management & undesirable least pain; (2) Adequate pain management & undesirable least pain; (3) Inadequate pain management & desirable least pain; and (4) Adequate pain management & desirable least pain [11, 13]. Grouping the PMI helps identify children with the most impactful pain, irrespective of fluctuations in pain intensity as both the highest and lowest moments of pain are accounted for. We found this approach purposeful for our study since pain in CP usually is chronic, recurrent and weak with acute exacerbations (of more severe pain) due to specific events (e.g. surgery or botulinum toxin injections) [5].

We also examined the type of pain treatment used and inquired into the prevalence, intensity, and anatomical location of the pain using a similar methodology as Eriksson et al. [1].

Methods

Results

Pain medication and other pain coping interventions

Characteristics of pain coping interventions are summarized in Table 2. 1/59 (0.02) subjects supplemented paracetamol with ibuprofen, gabapentin, and chlorzoxazone. The distribution of pain coping interventions used is illustrated in Figure 1. 34/59 (0.58) used any kind of non-pharmacological pain coping intervention for alleviating pain.

Table 2:

Characteristics of pain coping interventions used alone or in combination for 59 children with cerebral palsy that experience everyday pain.

Pain coping interventions used (alone or in combination)	Number of subjects (as fractions)
Massage	29/59 (0.49)
Paracetamol monotherapy	21/59 (0.36)
Physiotherapy	4/59 (0.07)
Other modalities (alone or in combination)	10/59 (0.17)
Temperature therapy	5/59 (0.09)
Foot bath	1/59 (0.02)
Solicitude	1/59 (0.02)
Distraction	1/59 (0.02)
Rest	4/59 (0.07)

1. Temperature therapy refers to using either cold or heat to alleviate pain by applying a temperature source, such as a heating pad, directly to an affected area. Foot bath refers to the placement of feet in heated water. Solicitude refers to parental attentiveness and emotional support. Distraction refers to shifting one’s focus away from pain and towards other activities or thoughts. Rest refers to discontinuing work or movement to facilitate relaxation, sleep, or recuperation of physical and mental stamina.

Figure 1:

Distribution of pain coping interventions used for 59 children with cerebral palsy that experience everyday pain.

41/59 (0.70) did not receive physician-prescribed pain-relieving pharmacological interventions, and 16/59 (0.27) subjects had pain-relieving interventions prescribed by a physician. 40/59 (0.68) parents indicated that they wanted further evaluation and intervention for their child. 48/59 (0.81) parents stated that their child could verbalize their pain and be able to identify pain location. The pain had a negative impact on their everyday life in 44/59 (0.75) when evaluated by their parents.

Pain intensity

The parental evaluation of categorical pain intensity is illustrated in Figure 2. Out of those with pain in their everyday life, 43/59(0.73) experienced it during procedures and activities, with 41/59 (0.70) experiencing pain during physical activity, 4/59 (0.07) while sitting or sleeping, and 6/59 (0.10) during other activities such as using the computer, doing homework, mental fatigue, fasting, using new shoes, or being without an orthosis.

Figure 2:

The categorization of pain intensity by parental evaluation of 59 children with cerebral palsy and everyday pain. We defined least pain as the lowest momentary pain intensity experienced, and worst pain as the highest momentary pain intensity experienced during pain. A numerical rating scale was used to grade the pain intensity of both the least pain and the worst pain, with 0 indicating no pain, 1–3 indicating mild pain, 4–7 indicating moderate pain, and 8–10 indicating severe pain.

Anatomical pain distribution

The distribution of pain in relation to anatomical location is shown in Figure 3, with a majority of subjects having lower extremity pain.

Figure 3:

Distribution of anatomical location of pain of 59 children with cerebral palsy by parental evaluation. Parents were able to select multiple pain locations.

Discussion

In this study, more than half of the children with CP in our region reported that they experienced chronic pain by parental proxy. Among those, about three-quarters were evaluated to be undertreated for their pain. Likewise, one-third were impacted by pain felt at both its highest and lowest moments of intensity. The majority who were in pain received alleviation through pharmacological and/or non-pharmacological interventions, with only a quarter using no pain interventions. The majority of parents of those in pain expressed a desire for further medical examination, while almost three-quarters of parents reported that the pain had a negative impact on their child’s daily living.

Based on the definition of chronic pain by the International Association for the Study of Pain (IASP), the fact that four-fifths with everyday pain experienced pain within the last week and 58 out of 59 experienced it within the last 3 months in this study indicates that their pain is indeed recurrent and chronic in nature [14, 19]. This sheds a light on an alarming clinical problem for children with CP, that in our opinion needs urgent attention in the medical community since pain is the primary determinant for reduced quality of life, missed school days, less participation in activities, and reduced ambulation [1, 5, 6, 20].

Previous studies have proposed that there exists a misconception among children with CP, their parents, and their treating physicians that pain is an unavoidable part of the disease itself, thus being inadequately or untreated and leaving the children to resign to living with pain [8, 21]. Our results suggest this as well throughout our region. Out of necessity, parents turn to undocumented and perhaps ineffective pain-coping interventions [10].

In our study, more than half utilized non-pharmacological and “complementary therapies” of massage, physiotherapy, or other conservative modalities, whereas pharmacological pain interventions were utilized less frequently. For pharmacological pain interventions, paracetamol was almost exclusively used as monotherapy instead of other prescription medicine, and we interpret the use of paracetamol as an over-the-counter medication without a prescription. Besides paracetamol, other nonopioid analgesic groups are often used for pain management in children with CP such as nonsteroidal anti-inflammatory drugs (NSAID), anticonvulsants such as gabapentin, and muscle relaxants such as baclofen [5, 9]. However, evidence of their effectiveness in treating pain in children, in particular with CP, is lacking, and many of these medications can cause potentially debilitating side effects, which complicates the implementation of them into straightforward pain management algorithms [5, 9, 17]. Of note, NSAIDs can potentially cause a variety of side effects, with gastrointestinal issues being a source of concern [22]. This is especially problematic as children with CP are already burdened with a high prevalence of gastrointestinal problems [23]. In our study, no instances of antispasmodic usage for pain were reported, which we interpret as possibly due to parents not viewing it as a pain-coping intervention. About half of the parents of children with CP in pain reported lessened pain after massage therapy. Pediatric massage therapy has been shown to decrease hypertonicity in those with CP, alleviating those with chronic pain conditions and subsequently lowering anxiety and depression [10, 24]. Almost one-fifth also described pain relief from other conservative initiatives such as seeking solicitude or distraction. Our findings indicate the need for professional implementation of complementary therapies in everyday pain management.

Three-quarters of those with everyday pain were evaluated to be inadequately treated. One-third in pain had both an inadequate pain treatment at the highest moments of pain intensity while also having an undesirable intensity of pain at its lowest moments. We find that this subset of children with bothersome pain felt regardless of pain fluctuations are particularly important to identify and treat.

We acknowledge that our study does have limitations. Firstly, our response rate of approximately two-fifths could give rise to a participation bias where the response to our questionnaire was more likely from those with pain in their everyday life. Investigating the group of non-responders could potentially have affected our results regarding pain. Our subjects were chosen as a convenience sample, thus our study could be influenced by selection bias from both factors. Although, for sex and GMFCS level, we found no significant difference between our cohort and that of the Danish national CP registry. This suggests that our study sample is representative of children with CP in our country. In the group of children that responded to our questionnaire by parental proxy, we found that older age, female sex, and increased GMFCS level did not have a significant impact on pain which has been suggested in some earlier studies [1, 5, 20, 25, 26]. Our overall pain prevalence in this study is comparable to methodically similar contemporary studies done approximately within the same age range as ours with findings between 42.5 and 49.6 percent [1, 25, 26], though a comparison of pain prevalence between studies is difficult due to study method disparities; in particular with differences in age groups and pain definitions [20]. Although we used responses from proxy reporting this should not influence our results [25]. Since our focus was evaluating the actual management of pain in children with CP, we explored a method to describe and evaluate the adequacy of the pain interventions used. Our modified PMI is limited in its approach to pain treatment in CP children as opioids of any type are determined as the appropriate analgesic for severe pain which should be prescribed within the principles of opioid stewardship [17]. As stated by WHOs’ guidelines for the management of chronic pain in children, opioids are usually indicated for terminal care and must be prescribed with a clear tapering plan [17]. Likewise, the hierarchical order of pain management in children is difficult to assess with evidence of pharmacological management being of low certainty evidence in comparison to the evidence of non-pharmacological pain interventions such as physical therapy (very low certainty evidence) and psychological therapy (moderate certainty evidence) [17]. Incorporation of non-pharmacological interventions in a pain ladder together with pharmacological interventions is challenging. The closest example would be WHO’s revised analgesic three-step ladder which added a bidirectional fourth step with interventional and minimally invasive procedures [27]. As such, our suggestion for pain management in children with CP is for an increased focus on psychological therapy, based on WHO’s moderately evidence-based recommendation [17]. Additionally, massage therapy has also shown promising results [10, 24]. It would also be beneficial for more healthcare providers to become aware of WHO’s guidelines for chronic pain management in children, which recommends implementing both non-pharmacological and pharmacological interventions together as part of a biopsychosocial model for pain management [17]. Moreover, the modification of the PMI was intended to provide a more comprehensive description of the pain management interventions actually used by parents, and to better assess their effectiveness in managing pain in children.

In conclusion, chronic pain is a prevalent issue for children with cerebral palsy, with approximately half of the children in our region experiencing everyday pain. Pain affected daily living for almost three-quarters of those in pain. The majority used pharmacological and non-pharmacological pain interventions with massage therapy and paracetamol being the most utilized. By our evaluation, pain management was inadequate for three-quarters of those in pain. Likewise, one-third of those in pain were impacted by their pain at both its highest and lowest moments of intensity. Increased awareness of pain management is warranted for children with CP.