Chapter 41
Pain in children

See Wan Tham¹, Jeffrey L. Koh², & Tonya M. Palermo³

¹ Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle Children’s Hospital and Research Institute, Seattle, Washington, USA

² Department of Anesthesiology and Peri-Operative Medicine, Oregon Health and Science University, Portland, Oregon, USA

³ Department of Anesthesiology and Pain Medicine, Pediatrics and Psychiatry, University of Washington School of Medicine, Seattle Children’s Hospital and Research Institute, Seattle, Washington, USA

Introduction

Children and adolescents have unique needs that should be considered in the assessment and management of pain. Across childhood, there is tremendous variability in neurocognitive development, physiology, and behavioral and emotional maturation that contribute to differences in presentations of pain. Moreover, the child’s determinants of health are nested within their hereditary genetics, family function and the social‐ecological system. These variabilities and vulnerabilities can define the pain experience and its trajectory as a chronic condition. Irrespective of whether pain is a symptom of a medical condition or a primary diagnosis, the evaluation and management can be challenging for the treating clinician. In this chapter, we review the considerations in managing pediatric chronic pain, including a discussion of its impact; a description of clinical evaluation and evidence‐based management approaches.

Etiology and significance of recurrent and chronic pain in children

Chronic or recurrent pain in children may be associated with underlying medical conditions, such as arthritis or inflammatory bowel disease. Pain may also be associated with life‐limiting and/or life‐threatening medical conditions, which may include cancer, end‐stage and palliative conditions. However, the most frequent form of chronic pain in children is when pain is the primary condition, not accounted for by another disease process. Examples are chronic headaches, musculoskeletal pain, functional abdominal pain or complex regional pain syndrome (CRPS). All forms of chronic pain irrespective of etiology can result in physical and psychosocial impairment and negatively impact children’s quality of life, such that pain itself becomes a primary or additional chronic problem.

Epidemiological studies provide prevalence estimates of recurring or persisting pain in 15–30% of children and adolescents [1, 2]. The most common locations involve the head, limbs, abdomen and back. Recurrent and chronic pain can lead to significant daily interference and pain‐related disability for an estimated 5–8% of children and adolescents [3]. Of concern are decrements in their ability to function in important life roles, including high rates of school absenteeism, poor academic achievement, as well as reduced participation in physical, social, recreational and peer activities [4]. Parents and family members may also be impacted such as through increased distress in caring for the child and financial hardship.

Conceptual models of chronic pain

Central to contemporary models of chronic pain are the interrelationships amongst physical, cognitive, affective and social factors that influence pain and disability – commonly referred to as biopsychosocial model of pain [5]. Current conceptualizations recognize the importance of each domain to understand pain in a comprehensive manner. The basis of assessment stems from elucidating the etiology of chronic and recurrent pain, of which central and peripheral nervous system mechanisms are implicated [6]. Processes of central sensitization and deficiencies in endogenous pain modulation are proposed to underlie persistent pain. More recently, neuroimmune and neuroendocrine interactions have been investigated to extend our understanding of chronic pain conditions. For example, the involvement of the brain‐gut axis in functional abdominal pain syndromes, and structural and functional brain changes in complex regional pain syndrome [7, 8]. Ongoing research highlights the complexity of pain mechanisms and the extensive systemic physiological involvement within each individual.

Using the framework of the biopsychosocial model, assessment of factors from each domain may organize a comprehensive approach to understanding the pain experience. From the biological and physiological standpoint, influences of age, sex, and aggregated family history of chronic pain have been highlighted. For example, females generally report higher pain intensity, longer lasting and more frequent pain than males [9]. With respect to psychological factors, children’s anxiety, depressive and catastrophizing symptoms have been found to have strong associations with pain intensity and pain‐related disability [10]. Social and environmental factors such as the role of parental influences have also been recognized as important in explaining the interindividual variability in children’s response to pain [11].

More recently, the World Health Organization’s International Classification of Functioning, Disability and Health (ICF) has been used to provide a framework for understanding the context and treating the impact of disease. In the evaluation of a health condition such as chronic pain, the environmental and personal factors of the child are incorporated, and overall activity and participation levels are assessed. This provides an understanding of the two primary concepts: “functioning” and “disability”. Functioning refers to physiological and anatomical integrity, which supports the ability to participate in activities and life roles. In contrast, disability highlights impairment in body function and structures, limiting activities and restricting participation [12]. With this approach, interventions can be systematically tailored to optimize the child’s health related quality of life as the primary target for treatment.

One of the challenges in treating pediatric chronic pain is the limited data on the natural history of pain. Available research suggests that up to half of children with chronic pain continue to have severe symptoms in adulthood [13, 14]. However, this also reflects that a large proportion of children and adolescents experience resolution and reduction in pain symptoms. This perspective allows for a more optimistic view in the treatment of pediatric chronic pain. The neuroplasticity of the pediatric nervous system has been proposed to contribute to the higher rates of resolution of pediatric pain compared to adult chronic pain conditions, although there is a paucity of data. Therefore, further research is critical to identify the risk factors across the biopsychosocial model that predict childhood pain, and to evaluate for vulnerabilities that maintain pain and disability during childhood through to adulthood. This will then give rise to the development of effective preventative and intervention strategies that may negate a lifelong trajectory of pain and disability [15].

Clinical practice: evaluation and treatment

Evaluation

The goals of the evaluation are to identify the etiology of pain, medical/psychological comorbidities, understand the context and impact of pain across all domains of functioning, and establish a therapeutic relationship. A productive way to initiate the history is to elicit the patient’s and parents’ narratives about the pain, rather than beginning with targeted questions. Further prompts about the pain history can then be provided. Throughout the evaluation, providing reassurance, rapport and validation of the pain problem will enhance receptivity of parents and child to the treatment approach. Details on the medical and psychological assessment are covered extensively in other texts [16].

In addition to the primary pain symptoms, children with chronic pain commonly suffer from comorbidities such as insomnia, anxiety or depression. Given the bidirectional relationships between sleep, pain and mood, it is important to identify potential concerns in these areas, as these comorbidities may interfere with rehabilitation. Standardized measures may be helpful to assess each domain of functioning (pain experience, psychological/physical functioning, disability) [17]. This can allow for objective monitoring of pain and function over time.

Treatment approach

The interdisciplinary model is the recommended treatment approach for pediatric chronic pain. An integrated rehabilitation strategy across disciplines has been shown to be more successful, in contrast to single target treatment that emphasizes complete symptom resolution or cure [18]. The team may consist of a pediatrician, anesthesiologist, nurse practitioner, pediatric psychologist, pediatric psychiatrist and physical or occupational therapist. To enhance team performance, key features include using a consistent treatment approach, providing clear and cohesive messaging to families, and maintaining regular communication.

It is recognized that education on the etiology of recurrent and chronic pain may be a driver of change in behaviors. When the pain experience is not validated or the diagnosis of chronic pain not understood, there is a risk that families may continue to seek further investigations and consultations, rather than engage in appropriate self‐management for pain. The International Association for the Study of Pain recognized that contemporary pain education is a central component of treatment (www.iasp‐pain.org). Providing information on scientific concepts to explain pain, its function, and biological processes has been found to be associated with reduced pain and disability, reduced catastrophizing, increased self‐efficacy, and increased participation in rehabilitation [19].

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