Chronic pain in children

The International Association for the Study of Pain (IASP) defines pain as "an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage".¹ Implicit in this definition is that pain is a subjective experience and is modulated not only by biological factors, but also by previously painful experiences, the meaning and context of the pain, fear, anxiety, depression, and a range of other factors.

Chronic pain is defined as continuous or recurrent pain that persists past the normal time of healing, most commonly about three months' duration.¹ If chronic pain refers simply to any pain with this predetermined duration, then all persistent pain of childhood, such as that related to chronic disease (eg, cancer, arthritis, sickle-cell disease), neuropathic pain (eg, complex regional pain syndrome, phantom limb pain) and recurrent pain syndromes (eg, migraine, recurrent abdominal pain), could be classified as causes of chronic pain in children.

Little is known about the epidemiology of chronic pain in children. A recent random survey of more than 6000 children in the Netherlands aged 0-18 years indicated an overall prevalence of 25%.² The prevalence of chronic pain increased with age, and was significantly higher for girls, particularly girls 12-14 years old. The most common types of pain were limb, abdominal pain or headache. Half of the respondents who had experienced chronic pain reported multiple sites of pain, and a third experienced pain as frequent and severe.² Multiple sites of pain and severe pain were reported more often by girls. The combination of headache and abdominal pain was reported most frequently. These findings indicate that chronic pain is common in children and adolescents.

In this issue of the Journal, Chalkiadis presents the first report on chronic pain in children in Australia.³ It is a prospective, descriptive study of the demographic and clinical characteristics of 207 children presenting to the Chronic Pain Clinic at the Royal Children's Hospital, Melbourne, over a two-year period. The study reveals that chronic pain had disturbing consequences for many children. The incidence of school absenteeism, sleep disruption and inability to play sport was high. Implied in these data is a significant psychological burden for the children and the families caring for them.

Despite a relatively high prevalence of chronic pain in paediatrics and its significant physical, psychological, social and economic impact on children and their families, it is often under-recognised by clinicians. The reasons for this are multiple and include children's dependency on caregivers to be their advocate. Children with chronic pain can often be met with a dismissive attitude from their caregivers, especially if no organic cause of their pain is found. Furthermore, the advancement in our understanding of the pharmacology of analgesics in children is a relatively recent development.⁴

The extent to which children may suffer from inadequately managed chronic pain is not known. Recently, in the United States, a major study of children in the terminal phase of cancer painted a chilling picture of suffering, including a high incidence of problems associated with the treatment of pain.⁵ According to the parents surveyed, 89% of the children suffered "a lot" or "a great deal" from at least one symptom in their last month of life, most commonly pain, fatigue, or dyspnoea. Of the children who were treated for specific symptoms, treatment was successful in 27% of those with pain and 16% of those with dyspnoea.⁵

Given the many physical and psychological variables in children experiencing chronic pain and the different modalities of treatment now available, the assessment of a child with chronic pain needs to be comprehensive. The team approach involves:

• an assessment of the physical, psychological and environmental parameters;

• developing pain management strategies, including pharmacological and non-pharmacological approaches; and

• individual and family therapy as required.

The long term outcomes of these strategies are not known, although Chalkiadis's report reveals at least short term benefit.

There has been a long-standing recognition of the need for a comprehensive assessment of chronic pain in adults. In Australia, this has led to multidisciplinary pain centres in many of the major teaching hospitals. In addition, five medical specialist bodies recently came together to form a single physician training program and examination process for the Faculty of Pain Medicine of the Australian and New Zealand College of Anaesthetists.

In contrast, it is only in recent years that a team approach to chronic pain in children has evolved in Australia and other countries. It is disturbing to read in Chalkiadis's report that only three paediatric centres in Australia and New Zealand have chronic pain management services which meet the minimum requirements for multidisciplinary staffing. Given the prevalence of chronic pain in children and the potentially serious physical and psychological consequences, a review of these services for children is required. On the basis of US data,⁵ strategies for the incorporation of pain management and palliative care principles into the care of children with life-threatening and life-limiting illness are a high priority.

John J Collins

Lynette J Lane

Susan Thompson

1. Merskey H, Bogduk N, editors. Classification of chronic pain: description of chronic pain syndromes and definitions of pain terms. Seattle: IASP Press, 1994.
2. Perquin CW, Hazebroek-Kampschreur AAJM, Hunfeld JAM, et al. Pain in children and adolescents: a common experience. Pain 2000; 87: 51-58.
3. Chalkiadis GA. Management of chronic pain in children. Med J Aust 2001; 175: 476-479.
4. McGrath PJ, Unruh AM, Branson SM. Chronic nonmalignant pain with disability. In: Tyler DC, Krane EJ, editors. Advances in Pain Research and Therapy. Volume 15. New York: Raven Press, 1988.
5. Wolfe J, Grier HE, Klar N, et al. Symptoms and suffering at the end of life in children with cancer. N Engl J Med 2000; 342: 326-333.

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