Chronic pain in children is a significant public health problem globally and a leading cause of morbidity in children.5–7 Pain is an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage or described in terms of such damage.4 Chronic pain is pain that persists or recurs for longer than three months. The 11th revision of the International Classification of Diseases (ICD-11) categorizes chronic pain as follows:4
Chronic primary pain
Chronic secondary pain
Chronic cancer-related pain
Chronic postsurgical or post traumatic pain
Chronic secondary musculoskeletal pain
Chronic secondary visceral pain
Chronic neuropathic pain
Chronic secondary headache or orofacial pain
Chronic pain, unspecified
Chronic primary pain is characterized by significant emotional or functional disability and is diagnosed independently of identified biological or psychological contributors. On the other hand, non-primary or secondary pain has a clear underlying etiology such as a disease, injury or lesion, or their treatment4 (e.g. surgery, chemotherapy, radiotherapy). Pain is a common symptom of many long-term conditions, such as cancer, sickle-cell disease, diabetes and arthritic conditions.
It is difficult to determine the prevalence and burden of chronic pain in children, and estimates vary widely due to differences in study populations including age, sample size, the definition of pain used, and how pain is measured.6 In addition, data from low- and middle-income countries are scant.8 Available studies suggest that chronic pain is experienced by about one-quarter to one-third of children,5,9–11 with about 1 in 20 experiencing moderate to high levels of pain-related disability.10 Among adolescents, a systematic review reported significant variation in pain prevalence across studies, ranging from 8% to 83% for headache, 14% to 24% for back pain, 4% to 53% for abdominal pain; 4% to 40% for musculoskeletal pain and 4% to 49% for multi-site pain.5 In a study set in a high-income country, 6% of children have chronic pain, with a higher prevalence among older children, children from low-income families, children using public insurance and children whose parents did not complete higher education.12 Some studies indicate even higher rates, particularly among adolescents. Data from the WHO collaborative cross-national Health Behaviour in School-aged Children (HBSC) study based on nationally representative samples of adolescents, revealed that 44% of adolescents reported chronic weekly pain during the last six months.6 Predictors of pain in adolescents included age and sex, with different demographic patterns and types of pain and locations across countries.6
Chronic pain negatively impacts the emotional, psychological, physical and social development and functioning of children and adolescents.13 Typically, children with moderate and severe pain report high levels of physical disability;14,15 emotional distress, anxiety and depression;15,16 sleep problems13 and poor academic performance2,17,18 compared to peers without chronic pain. Socially, such children do not attend school as often and report higher levels of feelings of isolation.18–20 Pain and the associated psychological distress and social consequences thus severely affect the quality of life of these children.2,8
Exposure to chronic pain in early life may have implications for the incidence, severity and duration of chronic pain, and may be associated with long-term, maladaptive neurological changes. Neuroimaging studies of children with acute pain and adults with chronic pain suggest that there are long-term changes in the structure, function and chemistry of the nervous system that correlate with subsequent cognitive, behavioural and somatosensory outcomes.21 Chronic pain in childhood is associated with progression of pain into adulthood2,22,23 and potentially predisposes these children to other chronic health problems in later life.21 The negative impacts of chronic pain also extend to family members who report a higher burden of care2,24 and a detrimental effect on family function.25 As such, chronic pain during childhood has a very significant negative impact on the child over their life course as well as their wider family unit, making appropriate diagnosis and management essential.
The economic effects of chronic pain and its management in children are also significant. Much of the data on costs incurred by the treatment of chronic pain come from adult populations: this condition is one of the most costly medical conditions in Western society.2,26 Data on children are extremely limited,27,28 although available data suggest that the costs in children are substantial also. Estimates for the economic burden of chronic pain in adolescents in the United Kingdom extended to US$ 9.5 billion and in the United States to US$ 19.5 billion annually (2012 US dollars)26–28. Children with chronic pain have high rates of health care utilization2,28,29 In addition, parents suffer significant financial consequences.26,27
Pain in children differs from that in adults for physiological, cognitive, developmental and social reasons,18,21 The child’s developmental processes lead to important and continuously changing differences in their perceptions, ability to express feelings and pain, as well as cognition and educational level.21 These differences in the pain experience as the child ages also relate to their environmental, cultural and social context, including for example their relationship to parents, caregivers and healthcare providers.21,25
The management of chronic pain in children is complex and challenging for a number of reasons. First, despite important differences between adults and children, there is a paucity of high-quality research studies on the treatment of chronic pain in children and adolescents.21 As a result, data from adults are inappropriately extrapolated to children. While there are some data on psychological therapy for pain in children and adolescents in high-income countries30 there is much less on physical31 and pharmacological therapies.32 Second, given the multiplicity of pain etiologies, and individual responses across patients and their families and caregivers, pain management requires an approach that is tailored to each child and their context. Third, a multimodal, interdisciplinary approach is required, which entails trained healthcare providers and a coordinated response. Fourth, chronic pain in children and adolescents impacts all aspects of the child’s and family’s life, and interventions must therefore address this broad context. Fifth, the diagnosis and optimal management of chronic pain in children may be adversely impacted by societal misperceptions and misinformation related to treatment modalities and their relative risks and benefits.
Finally, problems of inappropriate polypharmacy33 and drug marketing, the misuse of analgesic medicines and drug addiction, particularly related to opioids, have led to significant challenges. Studies have shown an increasing prevalence of prescription opioid use and misuse among American adolescents and young adults,34,35 which is associated with additional substance abuse.36,37
The United Nations Office of Drugs and Crime World Drug Report 201938 highlights the “global paradox of too much and not enough” and describes the difficulty of ensuring appropriate access to controlled substances for medical and scientific purposes while preventing their diversion and misuse. Every year almost 2.5 million children die with serious health-related suffering associated with the need for palliative care and pain relief, and more than 98% of these children are from developing regions.39 It is estimated that 5.5 billion people, or over 75 percent of the global population, have low to nonexistent access to opioid analgesics.40 Canada, Europe and the US contain approximately 17% of the world’s population, yet consume about 89% of the world’s supply of morphine (2013 data).41
There are a number of barriers to providing access to adequate pain management strategies including for vulnerable populations such as children, according to the Lancet Commission report of 2017 on palliative care and pain relief.39 These barriers include the medical community and policy-makers’ focus on extending life and productivity, opiophobia (prejudice and misinformation about the appropriate medical use of opioids), limited attention globally to non-communicable diseases, poor knowledge on the part of health professionals, and concerns about the nonmedical use of controlled substances. Very restrictive drug control regulations can interfere with appropriate therapeutic use of these medicines.39,42,43 International drug control conventions aim to remove barriers that limit the availability of and access to controlled drugs for medical use. These conventions are based on legal and regulatory frameworks, as well as on clinical guidelines addressing rational prescription practices.
The management of pain requires a broad, multimodal and interdisciplinary approach that addresses its physical, psychosocial and social dimensions. Children, including adolescents, have the right to appropriate treatments (physical, psychological and pharmacological) for pain management, and policy-makers and providers need to ensure appropriate access to these management strategies, while minimizing the potential harms of inappropriate use in society. Human rights norms require that pain management be incorporated as part of the basic health package under universal health coverage schemes.44
1.1. PURPOSE
In these Guidelines the World Health Organization (WHO) provides evidence-informed recommendations for the management of chronic pain in children. These recommendations are based on the most current, high-quality scientific evidence, and were formulated following processes and using methods meeting the highest international standards for guideline development.45
The purpose of these guidelines is to assist WHO Member States and their partners in developing and implementing evidence-informed national and local policies, regulations, pain management protocols and best practices. It will help countries balance concerns about ensuring access to appropriate therapies for pain relief with the harms arising from misuse of medications and other potential adverse effects of interventions for pain management. These guidelines also can help to empower families and caregivers to advocate for services and research, and indicate key research gaps which can help to focus future studies.
1.2. SCOPE AND TARGET AUDIENCE
These guidelines address the management of primary and secondary chronic pain in children 0 to 19 years of age, with a focus on physical, psychological and pharmacological interventions for pain relief. Relevant considerations were examined in population sub-groups where possible.
Not all potential therapies for chronic pain in children and adolescents are included in this edition of these guidelines. For example, interventional procedures for pain were not included as these interventions are less commonly delivered to children. In addition, while there may be possible roles for traditional and complementary medicine and practices in chronic pain management, these interventions were not included in the scope of these guidelines. The evidence base regarding their effectiveness and safety, as well as the quality assurance of interventions are being strengthened.46
These guidelines are intended for use by a wide range of audiences, including national and local policy-makers and their expert advisers, as well as technical and programme staff at organizations involved in the assessment, management, monitoring and education of children with chronic pain and their families. These guidelines may also be used by healthcare providers and their professional societies, and by researchers who are interested in addressing gaps in the evidence. Importantly, families and caregivers of patients with chronic pain can use these guidelines as a tool to better understand the management of this condition and the scientific evidence underlying the various interventions.
The audience for Guidelines for the management of chronic pain in children is a global one: it is intended for a wide range of settings with varied perspectives and resources. These guidelines are relevant to all Member States, including low-, middle- and high-income countries.
