Assessment of Chronic Pain in Children

Assessment of children with chronic pain starts with a biopsychosocial perspective to take into account the multiple factors that can influence the child’s pain experience. Multidimensional models elaborate various biologic, developmental, temperamental, cognitive-behavioral, affective, social, and situational factors that may both shape the child’s pain experience and influence the pathways by which they exert their effects. Each domain may become a target of assessment and intervention. Several developmentally sensitive validated instruments are now available to measure the varied aspects of children’s pain ( Table 33.1 ).

Two standardized interviews for school-age and adolescent children and their parents provide comprehensive yet practical evaluations of the child’s chronic pain—the Children’s Comprehensive Pain Questionnaire (CCPQ) and the Varni-Thompson Pediatric Pain Questionnaire (VTPPQ). These interviews separately assess both the child’s and parents’ experience of the pain problems with open-ended questions, checklists, and quantitative pain-rating scales. Some studies suggest potential limitations of these self-report measures because of cultural or cognitive differences among children. Additionally, the Pain Behavior Observation Method is a 10-minute observational pain behavior measure that can be used in children with chronic pain who may have difficulty with self-report measures because of age or cognitive limitations. Studies have supported the use of electronic versus paper pain diaries in children with chronic pain; electronic diary use was shown to be feasible and resulted in greater compliance and accuracy in diary recording than did traditional paper diaries in children with recurrent pain.

The well-documented comorbidity between pediatric chronic pain and psychiatric disorders, particularly internalizing disorders such as depression and anxiety, obligate the clinician to screen for these disorders. The Children’s Depression Inventory (CDI) is a widely used self-report questionnaire for assessing depression in children 7 to 17 years of age. The Beck Depression Inventory-II can be used with adolescents because some items on the CDI may be less age appropriate for older adolescents. It is important to assess for anxiety symptoms because pain-related disability is associated with anxiety sensitivity, a stable predisposition to fear of anxiety-related sensations, and pain-related avoidance behavior in children as well as adults with chronic pain. The Children’s Anxiety Sensitivity Index (CASI) is the only instrument thus far developed to assess this characteristic in children, and the Pain-Anxiety Symptoms Scale (PASS) was developed for adults to assess fear of pain but has been used in children as young as 8 years. A recent study suggested that the CASI is a better predictor of health-related quality of life than pain intensity in children with chronic pain.

Several well-validated self-report questionnaires assess anxiety in children (see Table 33.1 ). Two instruments, the Self-Report for Child Anxiety Related Disorders (SCARED) and the Spence Children’s Anxiety Scale (SCAS), include subscales that distinguish among specific anxiety disorders listed in the Diagnostic and Statistical Manual of Mental Disorders , Fourth Edition (DSM-IV). The Multidimensional Anxiety Scale for Children (MASC) and the Revised Children’s Manifest Anxiety Scale (RCMAS) include subscales that focus on other dimensions of anxiety. These subscales include physical symptoms, social and separation anxiety, and harm avoidance (the MASC) and physiologic symptoms, worry and oversensitivity, and concentration factors (the RCMAS); both also include social desirability items to detect inconsistency or randomness in reporting. The SCAS and SCARED provide both child and parent forms of the instrument, which allows examination of the convergence or lack thereof between the child’s and parent’s assessment of the child’s anxiety symptoms. The State-Trait Anxiety Inventory for Children (STAIC) provides a state version, which measures situation-specific anxiety, and a trait form, which assesses anxiety symptoms that are stable across situations.

Factors that are closely linked with a child’s ability to function with chronic pain, such as perceived stress and coping, can assist in planning behavioral interventions. The Pain Coping Questionnaire (PCQ), Pain Response Inventory (PRI), and Pain Catastrophizing Scale for Children (PCS-C) assess pain-specific coping strategies. The Response to Stress Questionnaire (RSQ) has been used to assess coping with abdominal pain but also has other versions that target other stressors, such as social stress. Identification and modification of maladaptive coping responses constitute core elements of cognitive-behavioral approaches for treating pediatric chronic pain. For example, if the child endorses a catastrophizing coping style, which is an established risk factor for poor adaptation to chronic pain, this coping style can become a target of treatment.

The ability to function in tasks of daily living is a critically important outcome measure to assess when treating children and adolescents with chronic pain. Frequently, pain cannot be completely relieved and the child must learn to accept, cope, and adapt to the pain to enable participation in normal developmental activities and tasks, such as going to school, participating in extracurricular activities, and developing and sustaining social relationships. Several measures have been developed to assess the child’s functional abilities, as well as quality of life. For example, the Pediatric Migraine Disability Scale (PedMIDAS) measures headache-related disability in children with chronic pain. This six-question tool assesses school, recreational, and social areas of participation and disability, domains relevant to all children with chronic pain. The Child Activity Limitations Interview (CALI) assesses the impact of recurrent pain on children’s daily activities as a way to identify appropriate targets for treatment. Additionally, the Functional Disability Inventory (FDI), developed to assess illness-related disability in children and adolescents, is a useful tool for evaluating the functional status of pediatric patients with chronic pain, a particularly important concern in children with pain disorders associated with psychological factors and pain-associated disability syndrome. Pain-related disability increases with age and as sex differences emerge in adolescence, with more girls than boys reporting pain-related functional disability.

Quality of life can also be assessed in children and adolescents with chronic pain and as an index of treatment progress, with one study finding that the quality of life of children with recurrent headaches is similar to that of children with rheumatoid arthritis or cancer. The Quality of Life Pain–Youth (QLP-Y) was developed to address quality-of-life issues particular to chronic pain. The Child Health Questionnaire, both child (CHQ-CF87) and parent reports (CHQ-50), as well as the PedsQL, are measures that may be used to assess general quality of life in children with chronic pain and have the advantage that the scores obtained on these instruments can be compared with standardized samples of scores obtained by children with other medical illnesses.

Other instruments that may further elucidate the psychological factors contributing to a child’s behavioral adaptation to chronic pain include the Children’s Somatization Inventory (CSI), which measures a child’s propensity to somatization, and the Harter Scales of Perceived Competence, which assess a child’s judgment about his or her capabilities in important domains such as school performance, peer relationships, and athletic abilities. The child’s own judgment of his or her competencies in these domains is useful in understanding other factors that may contribute to the child’s functioning. For example, children with chronic pain who rate themselves as low on social and academic competency may have multiple reasons to avoid returning to school.

Parental or family issues that could impede or support a child’s progress with treatment are also important to assess. The Family Environment Scale (FES) and the Family Adaptation and Cohesion Scales II (FACES II) have been used to assess family characteristics, whereas the Family Crisis-Oriented Personal Evaluation Scale (F-COPES) assesses the family’s problem-solving and coping efforts in relation to a challenging situation, such as having an ill child. At times the parents themselves may require psychiatric treatment to assist them in their efforts to help in their child’s rehabilitation. The Symptom Checklist 90–Revised (SCL-90-R) is a useful screen for parental psychiatric symptoms, and the Medical Outcomes Short-Form 36-Item Health Survey can be used to assess parental adaptive functioning, as well as disabilities.

Scharff and colleagues attempted to identify specific subgroups of pediatric chronic pain patients. Identifying subgroups of adults with chronic pain has proved useful in identifying patients’ coping efforts and determining appropriate psychological interventions. For example, the West Haven–Yale Multidimensional Pain Inventory (WHYMPI) has been used to identify clinical subgroups of adult chronic pain patients—“adaptive copers,” who have good coping and supportive relationships; “dysfunctional copers,” who have poor coping skills and are highly stressed; and the “interpersonally distressed,” who have inadequate social support. These three subgroups have been found in diverse adult populations with chronic pain and are associated with different outcomes in behaviorally based pain treatment programs. Although all three groups were found to benefit from a behavioral intervention, the dysfunctional copers benefited the most, with lower pain scores, decreased impact of the pain on their lives, and decreased depression and negative thoughts. Scharff and colleagues identified similar subgroups in a population of 117 children with various types of chronic pain conditions: a high-functioning group, a disabled and low-functioning group, and a group with family dysfunction. These strongly resemble the subgroups identified by Turk and Rudy in adult chronic pain patients. Although findings from this study were preliminary and need to be interpreted cautiously, such efforts to distinguish subgroups of children with chronic pain should serve to provide targeted treatments to improve the care of pediatric patients with chronic pain.

Therefore, thorough baseline and ongoing assessment is essential to guide interventions for chronic pain and evaluate the child’s response to treatment. Core elements of assessment include comprehensive evaluation of the child’s pain problem and screens for psychiatric comorbidity and functional status ( Box 33.2 ). More intensive screening of the child’s perceived stress and competencies and the parents’ and family’s functioning adds valuable information to treatment planning, especially in a child with long-standing pain problems that have not responded to previous treatment efforts.

Psychological Pain Management Methods

A rehabilitative approach that emphasizes improving the child’s and family’s ability to cope with a chronic condition characterizes the course of most chronic pain treatment programs for children. The focus shifts from the narrow goal of pain reduction, which might be used in the treatment of acute pain, and broadens to decrease pain-related emotional and behavioral disability, thereby increasing the child’s functional status. Psychological pain management methods are directed toward increasing the child’s and family’s understanding of the child’s pain and its treatment, including factors that may reduce or exacerbate the child’s pain, and enhancing cognitive and behavioral coping skills so that pain-related discomfort and disability are reduced. Research on the use of psychological therapies has focused mostly on clinical trials in children with headache. In a meta-analysis conducted to evaluate the efficacy of behavioral interventions for pediatric chronic pain, Eccleston and coworkers concluded that “There is strong evidence that psychological treatment, primarily relaxation and cognitive behavioural therapy, are highly effective in reducing the severity and frequency of chronic pain in children and adolescents.” Additionally, findings by Logan and colleagues suggest that interdisciplinary pediatric pain rehabilitation may facilitate increased willingness to self-manage pain, which is associated with improvements in function and psychological well-being.

A few promising psychological treatments have also been used for children with disease-related chronic pain, including sickle cell disease, recurrent abdominal pain, complex regional pain syndrome (CRPS) type 1, musculoskeletal pain, and juvenile primary fibromyalgia syndrome, and further support the probable efficacy of cognitive-behavioral approaches to pediatric pain management. Although there is evidence to support the use of single behavioral treatment modalities for the treatment of pediatric chronic pain, such as the use of thermal biofeedback and relaxation for recurrent pediatric headache, most treatment programs include a diverse array of techniques that treat chronic pain by modifying children’s cognitive, affective, and sensory experiences of pain, their behavior in response to pain, and environmental and social factors that influence the pain experience. Education about chronic pain and problem solving for improving the child’s functional status is central to the child and family assuming an active role in managing chronic pain. Cognitive techniques are targeted at modifying the child’s thoughts about the pain, in particular, to increase a sense of predictability and control over the pain, to alter memories about painful experiences, and to reduce negative cognitions about pain, especially “catastrophizing.” Decreasing somatic preoccupation, pain-related rumination, and passive coping and learning to accept that the pain may persist are also key interventional goals in the psychological management of pain.

Techniques to alter the sensory aspects of chronic pain include relaxation training, biofeedback, imagery, and hypnosis. Interventions aimed at modifying situational factors that exacerbate chronic pain and disability include contingency or behavioral management methods, modification of activity and rest cycles, and exposure to situations previously avoided because of pain. Few component analyses have been conducted to determine which psychological therapies may be most essential in the management of pediatric chronic pain, but it is likely that for most chronic pain conditions, a combination of modalities will provide the best opportunity to effect the desired change. Changes in the emphasis of various behavioral components may present the opportunity to individualize treatment for the specific child by taking into account developmental, psychological, parental, and family factors, which may provide a way to tailor specific treatment to a child.

There is growing acknowledgment of parents’ crucial role in successful rehabilitation of children with chronic pain, and thus they are increasingly becoming involved as active partners in their child’s treatment. Parental interactions with their child related to pain and the family characteristics of children with chronic pain that may be associated with the development of maladaptive coping with pain are areas of active research. Particular types of parental behaviors have been shown to influence a child’s ability to cope with pain. For example, parental attention has been associated with increased symptoms in children with recurrent abdominal pain. Walker and colleagues found that girls with functional abdominal pain are more vulnerable than boys to the symptom-reinforcing effects of parental attention. Interestingly, although the children with pain rated parental distraction as a helpful strategy, their patients rated distraction as having greater potential for a negative impact on their child than attention. Such findings help guide behavioral interventions for children with chronic pain and their families because parents’ beliefs in the most effective pain management strategies need to be targeted in any intervention designed to increase the functional abilities of children with chronic pain.

Several methods for the delivery of psychological interventions for recurrent or chronic pain in children have been shown to be effective, including those that involve intensive inpatient or outpatient treatment; those that are self-administered, school based, Internet-based, or CD ROM based ; and those that involve minimal clinic contact with home-based practice. The variety of methods for delivery of these interventions offers opportunities to reach a broad population of children with chronic pain, thus increasing the potential to reach many more children than can be treated in specialized pediatric pain treatment centers. Optimally, the child’s school and other caretakers are included in the treatment team to ensure a consistent and comprehensive approach to the child’s pain and disability. For example, if a child’s pain management involves strategies to cope with stress and headache at school, the school nurse can prompt the child to use these strategies rather than defaulting to having the parents pick the child up from school to rest at home (see Brown for a review of school issues related to pediatric pain). Complementary therapies such as massage and acupuncture are increasingly available to children seen in chronic pain clinics, but there is limited literature thus far to document the efficacy of these treatments in pediatric patients.

The complex nature of chronic pain in children creates many challenges in regard to its assessment and treatment, but this same complexity can be exploited to provide the most efficacious methods for pain control and functional rehabilitation. Multidimensional assessment provides the foundation for optimal pain management and functional rehabilitation of chronic pain in children. Psychological interventions include a diverse array of techniques that treat chronic pain by modifying children’s cognitive, affective, and sensory experiences of pain, their behavior in response to pain, and environmental and interactional factors that influence the pain experience. Without addressing the factors that may contribute to pain and pain-related disability, medical treatment of a child’s chronic pain may result in poorer outcomes. Research informed by multidimensional models of pediatric chronic pain can guide investigators in efforts to identify effective pain treatments, as well as the individual children for whom they work best. Finally, the lessons learned about optimal management of pain in children need to be practiced to the fullest extent possible so that the incidence of their suffering and disability may be diminished. For further reviews of psychological interventions for pediatric chronic pain, see McGrath and Holahan, Hillier and McGrath, and Eccleston and coworkers.

Psychological Pain Management Methods

A rehabilitative approach that emphasizes improving the child’s and family’s ability to cope with a chronic condition characterizes the course of most chronic pain treatment programs for children. The focus shifts from the narrow goal of pain reduction, which might be used in the treatment of acute pain, and broadens to decrease pain-related emotional and behavioral disability, thereby increasing the child’s functional status. Psychological pain management methods are directed toward increasing the child’s and family’s understanding of the child’s pain and its treatment, including factors that may reduce or exacerbate the child’s pain, and enhancing cognitive and behavioral coping skills so that pain-related discomfort and disability are reduced. Research on the use of psychological therapies has focused mostly on clinical trials in children with headache. In a meta-analysis conducted to evaluate the efficacy of behavioral interventions for pediatric chronic pain, Eccleston and coworkers concluded that “There is strong evidence that psychological treatment, primarily relaxation and cognitive behavioural therapy, are highly effective in reducing the severity and frequency of chronic pain in children and adolescents.” Additionally, findings by Logan and colleagues suggest that interdisciplinary pediatric pain rehabilitation may facilitate increased willingness to self-manage pain, which is associated with improvements in function and psychological well-being.

A few promising psychological treatments have also been used for children with disease-related chronic pain, including sickle cell disease, recurrent abdominal pain, complex regional pain syndrome (CRPS) type 1, musculoskeletal pain, and juvenile primary fibromyalgia syndrome, and further support the probable efficacy of cognitive-behavioral approaches to pediatric pain management. Although there is evidence to support the use of single behavioral treatment modalities for the treatment of pediatric chronic pain, such as the use of thermal biofeedback and relaxation for recurrent pediatric headache, most treatment programs include a diverse array of techniques that treat chronic pain by modifying children’s cognitive, affective, and sensory experiences of pain, their behavior in response to pain, and environmental and social factors that influence the pain experience. Education about chronic pain and problem solving for improving the child’s functional status is central to the child and family assuming an active role in managing chronic pain. Cognitive techniques are targeted at modifying the child’s thoughts about the pain, in particular, to increase a sense of predictability and control over the pain, to alter memories about painful experiences, and to reduce negative cognitions about pain, especially “catastrophizing.” Decreasing somatic preoccupation, pain-related rumination, and passive coping and learning to accept that the pain may persist are also key interventional goals in the psychological management of pain.

Techniques to alter the sensory aspects of chronic pain include relaxation training, biofeedback, imagery, and hypnosis. Interventions aimed at modifying situational factors that exacerbate chronic pain and disability include contingency or behavioral management methods, modification of activity and rest cycles, and exposure to situations previously avoided because of pain. Few component analyses have been conducted to determine which psychological therapies may be most essential in the management of pediatric chronic pain, but it is likely that for most chronic pain conditions, a combination of modalities will provide the best opportunity to effect the desired change. Changes in the emphasis of various behavioral components may present the opportunity to individualize treatment for the specific child by taking into account developmental, psychological, parental, and family factors, which may provide a way to tailor specific treatment to a child.

There is growing acknowledgment of parents’ crucial role in successful rehabilitation of children with chronic pain, and thus they are increasingly becoming involved as active partners in their child’s treatment. Parental interactions with their child related to pain and the family characteristics of children with chronic pain that may be associated with the development of maladaptive coping with pain are areas of active research. Particular types of parental behaviors have been shown to influence a child’s ability to cope with pain. For example, parental attention has been associated with increased symptoms in children with recurrent abdominal pain. Walker and colleagues found that girls with functional abdominal pain are more vulnerable than boys to the symptom-reinforcing effects of parental attention. Interestingly, although the children with pain rated parental distraction as a helpful strategy, their patients rated distraction as having greater potential for a negative impact on their child than attention. Such findings help guide behavioral interventions for children with chronic pain and their families because parents’ beliefs in the most effective pain management strategies need to be targeted in any intervention designed to increase the functional abilities of children with chronic pain.

Several methods for the delivery of psychological interventions for recurrent or chronic pain in children have been shown to be effective, including those that involve intensive inpatient or outpatient treatment; those that are self-administered, school based, Internet-based, or CD ROM based ; and those that involve minimal clinic contact with home-based practice. The variety of methods for delivery of these interventions offers opportunities to reach a broad population of children with chronic pain, thus increasing the potential to reach many more children than can be treated in specialized pediatric pain treatment centers. Optimally, the child’s school and other caretakers are included in the treatment team to ensure a consistent and comprehensive approach to the child’s pain and disability. For example, if a child’s pain management involves strategies to cope with stress and headache at school, the school nurse can prompt the child to use these strategies rather than defaulting to having the parents pick the child up from school to rest at home (see Brown for a review of school issues related to pediatric pain). Complementary therapies such as massage and acupuncture are increasingly available to children seen in chronic pain clinics, but there is limited literature thus far to document the efficacy of these treatments in pediatric patients.

The complex nature of chronic pain in children creates many challenges in regard to its assessment and treatment, but this same complexity can be exploited to provide the most efficacious methods for pain control and functional rehabilitation. Multidimensional assessment provides the foundation for optimal pain management and functional rehabilitation of chronic pain in children. Psychological interventions include a diverse array of techniques that treat chronic pain by modifying children’s cognitive, affective, and sensory experiences of pain, their behavior in response to pain, and environmental and interactional factors that influence the pain experience. Without addressing the factors that may contribute to pain and pain-related disability, medical treatment of a child’s chronic pain may result in poorer outcomes. Research informed by multidimensional models of pediatric chronic pain can guide investigators in efforts to identify effective pain treatments, as well as the individual children for whom they work best. Finally, the lessons learned about optimal management of pain in children need to be practiced to the fullest extent possible so that the incidence of their suffering and disability may be diminished. For further reviews of psychological interventions for pediatric chronic pain, see McGrath and Holahan, Hillier and McGrath, and Eccleston and coworkers.

Chronic Pain Syndromes

We briefly discuss the diagnosis and management of some common chronic pain syndromes diagnosed in pediatric patients referred to chronic pain clinics. The introduction of multidisciplinary pediatric pain clinics has allowed children to be seen in a single office visit by a number of consultants who are able to provide service for the child and develop a comprehensive pain management plan. Our clinic includes an anesthesiologist specialized in pain management, a child psychologist with a special interest in pain, a physical therapist, a complementary medicine practitioner (including message therapy and acupuncture therapy), and a specialist in biofeedback. This comprehensive approach reduces the need for multiple visits and exposes our patients to a multimodal therapeutic approach.

Common pain syndromes in children include CRPS type 1, headache, abdominal pain, chest wall pain, back pain, pelvic pain, and cancer-related pain. We address each of these conditions with a specific emphasis on accepted current therapy.

Complex Regional Pain Syndrome Type 1

CRPS 1, or reflex sympathetic dystrophy (RSD) as it was originally called, is a complex syndrome consisting of pain, allodynia, hyperalgesia, and possible loss of function. The International Association for the Study of Pain (IASP) has defined CRPS 1 as “A continuous pain in a portion of an extremity after trauma, which may include fracture but does not involve major nerve lesions and is associated with sympathetic hyperactivity.” CRPS 1 is a common reason for referral to a pediatric pain clinic. It is seen more commonly in the lower extremity, and most of the children involved are female, many of whom have endured minor trauma before the development of chronic pain. Though reported in a 2½-year-old girl, it is generally seen in children older than 9 years and more frequently in girls 11 to 13 years of age. Early recognition and management are the major factors in improving outcome and preventing resistant CRPS. Management by an experienced multidisciplinary team is recommended. Because psychosocial factors play an important role, psychological evaluation and cognitive-behavioral treatment should be provided in an expeditious manner.

The mechanisms that generate neuropathic pain (NP) are varied and complex. Injuries to peripheral nerves may involve crush, transection, compression, demyelination, axonal degeneration, inflammation, ischemia, or other processes. The primary loci of increased irritability following peripheral nerve injury may be at several levels in the nervous system, including axonal sprouts or neuroma, the dorsal root ganglia, the dorsal horn of the spinal cord, or sites more rostral in the central nervous system. Central neural causes and peripheral small-fiber neuropathy have been implicated in the mechanisms leading to NP. NP rarely keeps the subject from harm because it involves the erroneous generation of impulses.

Evaluation of Neuropathic Pain

History

A detailed history of the nature of the injury, the type and duration of the pain, relieving and aggravating factors, and dependence on medications is mandatory before evaluation.

Physical Evaluation

A thorough and systematic neurologic examination should be performed. Complete evaluation of motor, sensory, cerebellar, cranial nerve, reflex, cognitive, and emotional functioning is important. A concerted effort must be made to rule out a rare but possible malignancy or central degenerative disorder.

Sympathetically mediated pain is often diagnosed by clinical and diagnostic criteria based on responses to sympathetic blocks. However, the diagnosis of sympathetically mediated pain cannot be based on responses to sympathetic blocks alone.

The strength of the extremity should be evaluated on several occasions. It is important to compare it with the strength in the contralateral extremity because CRPS 1 can occur in both extremities at the same time.

Allodynia is excruciating pain that can be produced by innocuous stimuli such as stroking (e.g., stroking the skin with a feather). This is very characteristic of NP. Tactile allodynia in the absence of skin problems is a classic diagnostic criterion for NP.

Hyperalgesia is an increased sensitivity to pain. Hyperalgesia to cold is seen more frequently than hyperalgesia to warmth. The distribution is not generally restricted to particular dermatomes, as in an adult, and commonly occurs along a glove-and-stocking distribution.

Nerve conduction studies may provide some insight into the location and type of nerve injury. However, the use of invasive electromyography may not be acceptable to children.

Quantitative sensory testing (QST) with thermal and vibration sensations and thermal pain detection thresholds in the affected limbs can be compared with data from normal healthy children. The patient’s rating of pain and quality of pain can be assessed. Mechanical static allodynia and dynamic allodynia can be measured. Quantitative thermal and vibration detection thresholds can be measured. Although this involves cumbersome equipment, bedside QST may have a greater role in the diagnosis of CRPS 1 in children and adolescents.

Bone scans may be helpful in the diagnosis of CRPS 1. Although there are not enough data on their diagnostic accuracy in children, they are nevertheless performed in children and adolescents with CRPS 1. A decrease in isotope uptake is noticed with CRPS 1.

Diagnosis

Diagnosis of CRPS 1 in children is usually based on symptoms and signs ( Box 33.3 ). The characteristics of the pain and sensory, motor, and sudomotor changes may vary among patients ; also, differences between NP and nociceptive pain can be noted ( Table 33.2 ). A test with phentolamine has been used to confirm the diagnosis and to predict the response to sympathetic blockade. Bone scans may offer some information about CRPS 1. Disturbed vascular scintigraphy with increased pooling in the initial phase and hyperfixation on bone scintigraphy may denote the presence of CRPS 1. The IASP criterion for CRPS 1 is applicable to children and adolescents (see Box 33.3 ). Classic signs and symptoms of the various stages of CRPS 1 are presented in Table 33.3 .

Box 33.3

• 1.
  

  Presence of an initiating noxious event or cause of immobilization

  
  
• 2.
  

  Continuous pain, allodynia, or hyperalgesia in which the pain is disproportionate to any known inciting event

  
  
• 3.
  

  Evidence at some time of edema, changes in blood flow, or abnormal sudomotor activity in the region of pain

  
  
• 4.
  

  Diagnosis excluded by the existence of other conditions that would otherwise account for the degree of pain and dysfunction

International Association for the Study of Pain Diagnostic Criteria for Complex Regional Pain Syndrome

Adapted from Bruehl S, Harden RN, Galer BS, et al. External validation of IASP diagnostic criteria for complex regional pain syndrome and proposed research diagnostic criteria. International Association for the Study of Pain. Pain . 1999;81:147-154.

Table 33.2

Differences Between Neuropathic and Nociceptive Pain

Characteristic	Neuropathic Pain	Nociceptive Pain
Description of pain	Burning, lancinating, pins and needles	Varied
Tactile allodynia	Present	Absent
Duration and intensity of pain	Increases with duration	Decreases
Opioid resistant	Present	Absent
Use of tricyclic antidepressants	Useful	Not useful

Table 33.3

Symptoms and Changes in Stages of Chronic Regional Pain Syndrome Type 1

Characteristic	Acute	Dystrophic	Atrophic
Pain	Hyperpathic, burning	Chronic
Blood flow	Increased	Decreased	No change
Temperature	Increased	Decreased	No change
Hair and nail growth	Increased	Decreased	Chronic change
Sweating	Decreased	Increased	No change
Edema	None	Brawny edema	Wasted muscles, atrophic skin
Color	Red	Cyanotic	Atrophic

Treatment of Neuropathic Pain

Management of NP ( Box 33.4 ) can be frustrating for the caregiver, as well as the patient. No single therapy can uniformly provide relief to these patients. Management depends largely on the response to various clinical measures. Titration of medications is limited by the presence of side effects and complications. One of the primary goals is to return the child to a functional state and to school. Definitive resolution of the pain is not always possible. Most management techniques have been extrapolated from work done in adult patients. It is imperative to build trust with the patient and the parents. Family dynamics are important because the added burden of familial disharmony or parental abuse can worsen the symptoms. There seems to be a greater propensity for enmeshment in these families. The algorithm shown in Figure 33.1 is used by our pain clinic.

Box 33.4

Nonpharmacological Treatment

• 
  

  Hypnosis, biofeedback, visual guided imagery

  
  
• 
  

  TENS, physical therapy, occupational therapy

  
  
• 
  

  Individual and family therapy (day program if required)

Pharmacological Therapy

• 
  

  Acetaminophen, NSAIDs

  
  
• 
  

  Tricyclic antidepressants (e.g., amitriptyline, nortriptyline, doxepin); start at low doses, 0.1 mg/kg, and advance slowly

  
  
• 
  

  Anticonvulsants (gabapentin, pregabalin, carbamazepine, phenytoin, clonazepam), systemic local anesthetics (mexiletine, lidocaine)

  
  
• 
  

  Serotonin and norepinephrine reuptake inhibitors

  
  
• 
  

  Opioids (morphine, methadone given orally, intravenously, or via regional technique [epidural or intrathecal], especially in cancer patients)

Regional Blockades for Chronic Pain

• 
  

  Epidural, subarachnoid and sympathetic plexus, peripheral catheter blockade

  
  
• 
  

  Sympathetic blockade for CRPS 1

  
  
  
  
  • 
    

    Continuous catheter techniques may be used for 5 to 7 days

    
    
  • 
    

    Epidural and subarachnoid block for cancer patients: left in place for longer periods by tunneling subcutaneously

    
    
  • 
    

    Neurolytic blockade for cancer

  
  

CRPS, complex regional pain syndrome; NSAIDs, nonsteroidal anti-inflammatory drugs; TENS, transcutaneous electrical nerve stimulation.

Management of Neuropathic Pain

Algorithm for the management of chronic regional pain syndrome type 1. IVRA, intravenous regional anesthesia; SNRIs, serotonin norepinephrine reuptake inhibitors; TCAs, tricyclic antidepressants; TENS, transcutaneous electrical nerve stimulation.

Psychological and Behavioral Therapy

Behavioral measures are extremely useful in the management of NP. Family therapy often helps family members cope with the situation. We generally advocate consultation with a medical psychologist during the initial visit to the pain clinic. Several techniques, including biofeedback, visual guided imagery, and structured counseling, have been shown to assist in the development of adequate coping skills. Participation in a day program for acute psychological intervention has been valuable for some of our patients, specifically those with significant psychiatric co-illness. See earlier for more detailed explanations of various psychological interventions.

Physical Therapy

Physical therapy is geared toward adequate functional ability of the child. Transcutaneous electrical nerve stimulation (TENS) is widely used, and its efficacy has been studied in adults as well as children; therapeutic benefits with TENS in children with RSD have been reported by Kesler and colleagues. We use TENS extensively in our practice, along with physical therapy, which consists of both active and passive physical modalities. The physical therapy program is geared toward individual patients, and the goal is to allow the child to participate in as many activities as possible. It may be necessary to have input from a pediatric physical therapist or occupational therapist for adequate management. Other commonly used modalities include desensitization, warm and cold baths, massage therapy, and heat therapy. Such modalities, when used in conjunction with active physical modalities, can help ameliorate the pain symptoms.

Medical Therapy

Most of the work in children has been extrapolated from the experience in adults. It is best to start with nonsteroidal anti-inflammatory drugs (NSAIDs) in moderate doses, followed by other medications (see Box 33.4 ). There are certain differences between adult and pediatric patients:

• 1.
  

  Symptoms of NP may differ in children and adults.

  
  
• 2.
  

  The response to medications may be different.

  
  
• 3.
  

  There may be unrecognized toxicity to medications.

Tricyclic Antidepressants

Adults are frequently prescribed tricyclic antidepressants (TCAs) for the management of NP. Despite the lack of adequately controlled studies in pediatric patients, TCAs are widely prescribed for several forms of NP. Because amitriptyline may cause sedation, it is our practice to use nortriptyline, which appears to have less sedative and fewer anticholinergic side effects. Thorough examination of the cardiovascular system is necessary before instituting TCA treatment because of associated tachydysrhythmia and other conduction abnormalities of the heart, particularly prolonged QT syndrome.

Anticonvulsants

Anticonvulsant medications have been used for several years to manage NP. Although carbamazepine and oxcarbazepine have been used extensively to treat NP, the introduction of gabapentin and pregabalin has revolutionized the world of pain medicine. Despite the lack of controlled trials in children to demonstrate the efficacy of either drug, both of these voltage-gated calcium channel blockers have been used in our clinic with promising results. More controlled trials need to be conducted to better determine the dosing and efficacy of this class of drugs in children with CRPS 1. An important side effect that we have noted in our clinic setting is the potential for increased somnolence, as well as the potential for weight gain in children taking pregabalin. This is important to consider, especially when treating adolescent girls, who happen to be the majority of this cohort.

Selective Serotonin Reuptake Inhibitors and Serotonin-Norepinephrine Reuptake Inhibitors

Despite the lack of proven efficacy of the use of selective serotonin reuptake inhibitors in the management of pain in children and adolescents, they are occasionally used to treat psychological comorbidity, including depression associated with pain. More recently, serotonin-norepinephrine reuptake inhibitors have been introduced and used successfully to treat NP, especially in patients with psychological comorbidity.

Opioids

Opioids can be helpful in the management of NP, especially for cancer-related NP (see later). Arner has shown that several types of NP are resistant to the effects of opioids. Opioids should be titrated in a graded fashion to optimize the effect. Sedation is a side effect that may be desirable, especially in cancer-related NP, and in some cases it may need to be antagonized with the addition of amphetamines. For children with non–cancer-related NP, non–opioid-based techniques are generally exhausted before starting opioids.

Systemic Vasodilators

Several patients with RSD have benefited from the use of vasodilators such as prazosin, nifedipine, and phenoxybenzamine. However, overwhelming adverse effects of orthostatic hypotension often offset the efficacy of this therapy.

Regional Anesthesia and Sympathetic Blocks

A common treatment of these syndromes is to interrupt the apparent pathologic reflexes by performing sympathetic blocks ( Box 33.5 ). Regional anesthesia, though used often in adults for the diagnosis and management of CRPS, is generally introduced in children after pharmacological and cognitive-behavioral management has been exhausted. In severe cases, regional anesthesia is used to introduce a physical therapy regimen. In this section we discuss the different regional techniques that are used in children for the management of CRPS.

Box 33.5

• 
  

  Intravenous regional anesthesia—guanethidine, bretylium, lidocaine-ketorolac

  
  
• 
  

  Epidural analgesia (continuous)

  
  
• 
  

  Intrathecal analgesia

  
  
• 
  

  Sympathetic chain blocks

  
  
  
  
  • 
    

    Stellate ganglion blocks

    
    
  • 
    

    Lumbar sympathetic blocks

  
  
  
  
• 
  

  Brachial plexus catheters

  
  
• 
  

  Sciatic nerve catheters

Regional Anesthesia for Complex Regional Pain Syndrome Type 1

Central neuraxial blockade is used in children with severe pain to facilitate the introduction of physical therapy. An indwelling epidural catheter is placed in the lumbar or cervical area and infused with a low-concentration local anesthetic solution, which allows better cooperation from the patient and the parents to introduce a physical therapy regimen. In addition, intrathecal analgesia has been reported to be an effective method for treating refractory CRPS 1 in children.

Bier block has been used for mild to moderate cases of CRPS 1 as a primary modality for providing analgesia and sympathetic blockade. Although a myriad of substances have been used to provide a Bier block, a local anesthetic in combination with either an α ₂ -agonist or an NSAID appears to produce better results. In our case series of children who received intravenous regional anesthesia with lidocaine and ketorolac, we demonstrated a marked improvement in symptoms and the ability to perform physical therapy.

Peripheral nerve blocks are used to facilitate physical therapy while providing a sympathectomy and have become more plausible, especially with the use of ultrasound guidance. Serial peripheral nerve blocks may be performed. With serial blocks, the patient’s pain relief often outlasts the duration of conduction blockade, which may be due to reduced central sensitization, as well as interruption of the circuit established between the nociceptor, central nervous system, and motor unit. Concomitant corticosteroid administration may contribute to this effect via anti-inflammatory action and by suppressing ectopic discharge in neural membranes. We have noted these effects in our practice. The majority of our patients with NP who have undergone serial peripheral nerve blocks experience pain relief that increases in duration with each block.

Continuous peripheral nerve blocks (CPNBs) have been reported to be effective in both controlling pain and facilitating physical therapy in children with CRPS. Despite such reports, limited data exist regarding the feasibility, safety, and efficacy of CPNBs in children. After perineural catheter placement, a dilute solution of local anesthetic is infused with the view of providing analgesia while allowing physical activity. The catheter is left in place for 4 to 5 days; this can be done on an inpatient basis, or the patient may be sent home with a portable infusion device. We prefer sciatic nerve catheter placement for the lower extremities (see Fig. 33.2 ) and interscalene or infraclavicular brachial plexus catheters for the upper extremities. Concurrent physical therapy is indicated to improve range of motion and function. We institute physical therapy at the time of provision of a nerve block to enhance the patient’s experience with therapy.

Sciatic nerve catheter for the management of complex regional pain syndrome type 1.

Sympathetic blockade is used in children after exhausting the aforementioned techniques. A stellate ganglion block may be performed under ultrasound guidance for upper extremity CRPS (see Fig. 33.3 ), and a lumbar sympathetic block is performed under fluoroscopic guidance for lower extremity CRPS. A crossover trial of fluoroscopically guided lumbar sympathetic blocks demonstrated a decrease in allodynia and pain intensity when compared with intravenous injection of lidocaine in adolescents with CRPS.

Image of ultrasound-guided stellate ganglion blockade.

Neuromodulation via spinal cord stimulation, though commonly performed in adults for refractory cases of CRPS, is very rarely used in the pediatric setting. Spinal cord stimulation has been reported to achieve favorable outcomes in adolescents with therapy-resistant CRPS. The use of peripheral nerve stimulators, however, is gaining ground in the pediatric setting and may benefit children with refractory CRPS.

Prognosis of Neuropathic Pain

Varni and colleagues reported uniform improvement in their series of patients who endured a prolonged course of physical therapy and inpatient rehabilitation. Ashwal and associates concluded that the prognosis of childhood CRPS is more favorable than that of adult CRPS. NP can be puzzling and frustrating and requires a strong alliance with the family and the patient. A multidisciplinary algorithmic management approach involving the use of available techniques can be helpful. The use of physical therapy and psychological management must be stressed while managing these patients.

Headaches in Children

Headaches are a common finding in children and adolescents. Few physicians discussed headaches in children until 1873, when William Henry Day, a British pediatrician, devoted a chapter to the subject of headaches in his book Essays on Diseases in Children . In 1967, Freidman published the data available in Headaches in Children . These books provided an impetus to the many subsequent papers dealing with headaches in children. Many child care providers do not believe that children have an appreciable number of headaches. In a study of 9000 children in Sweden, Bille reported migraine headaches in 3.9% of children younger than 12 years and a 6.8% incidence of nonmigrainous headaches daily. This translates to a greater number of school days lost from absenteeism because of the debilitating nature of the headaches. A more recent study by Bille demonstrated that almost 40% of these children with headaches in childhood progress to a headache-free state in adulthood. A 2010 survey of middle schools in the Chicago area demonstrated the presence of headaches in a large percentage of all schoolchildren.

Most headaches in children are linked to either organic or nonorganic causes and may be deemed acute or chronic based on the duration of the headaches. Chronic daily headache is classified as headaches that occur at least 15 times monthly for a period of 3 months and can last for more than 4 hours daily.

Evaluation of Headache

A thorough history and physical examination help determine the nature of the headache. Specific questions about neurologic symptoms such as ataxia, lethargy, seizures, or visual impairment should be asked. Other medical conditions such as hypertension, sinusitis, and emotional disturbances must be evaluated. Physical examination, including a thorough neurologic examination and blood pressure measurement, is mandated for children with headaches. Neuroimaging may be required and a lumbar puncture might be advised in some cases. Benign intracranial hypertension or idiopathic intracranial hypertension is a constellation of symptoms and signs that includes headaches, diplopia, tinnitus, and eye pain. These conditions usually have normal imaging results. Although a diagnostic lumbar puncture may be needed in some settings, patients with chronic daily headaches may be prone to post–lumbar puncture headaches.

Pathophysiology of Headache

A headache is modulated by extracranial as well as intracranial structures ( Box 33.6 ).

Box 33.6

Pain-Sensitive Headache

• 
  

  Extracranial

  
  
  
  
  • 
    

    Skin

    
    
  • 
    

    Subcutaneous tissue

    
    
  • 
    

    Muscles

    
    
  • 
    

    Mucous membranes

    
    
  • 
    

    Teeth

    
    
  • 
    

    Larger vessels

  
  
  
  
• 
  

  Intracranial

  
  
  
  
  • 
    

    Vascular sinuses

    
    
  • 
    

    Larger veins

    
    
  • 
    

    Dura surrounding the veins

    
    
  • 
    

    Dural arteries

    
    
  • 
    

    Arteries at the base of the brain

  
  

Pain-Insensitive Headache

• 
  

  Brain

  
  
• 
  

  Cranium

  
  
• 
  

  Most of the dura

  
  
• 
  

  Ependyma

  
  
• 
  

  Choroid plexus

Pathophysiology of Headache

Classification of Headache

Classification of headaches is based on the presumed location of the abnormality, its origin, its pathophysiology, or the symptom complex that the patient has ( Box 33.7 ).

Box 33.7

• 
  

  Acute headache

  
  
  
  
  • 
    

    Systemic illness

    
    
  • 
    

    Subarachnoid hemorrhage

    
    
  • 
    

    Trauma

    
    
  • 
    

    Toxins such as lead or carbon monoxide

    
    
  • 
    

    Electrolyte imbalances

    
    
  • 
    

    Hypertension

  
  
  
  
• 
  

  Acute recurrent headache

  
  
  
  
  • 
    

    Migraine

  
  
  
  
• 
  

  Chronic progressive headaches

  
  
  
  
  • 
    

    Organic brain disease

    
    
  • 
    

    Ventriculoperitoneal shunt malfunction

  
  
  
  
• 
  

  Chronic nonprogressive headache

  
  
  
  
  • 
    

    Functional in quality

  
  
  
  
• 
  

  Mixed headache

Classification of Headaches: Differential Diagnosis

Evaluation of Headache

Comorbid symptoms are associated with headaches. The most common comorbidity is sleep deprivation. Delayed sleep is a frequent disorder seen in children with headaches. Many also have symptoms of dizziness, which may be associated with postural hypotension and tachycardia (postural orthostatic tachycardia syndrome). Orthostatic hypotension should be treated by increasing fluid intake, and in some cases, a β-blocker may be needed. A history of a new-onset severe headache, pain that awakens a child from sleep, headaches associated with straining, changes in chronic headache patterns, or the presence of a headache accompanied by nausea or vomiting suggests a more pathologic origin of the headache and must be carefully evaluated ( Box 33.8 ).

Box 33.8

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related

Related posts:

The History of Pain Medicine A Review of Pain-Processing Pharmacology Electromyography and Evoked Potentials Neuropathic Pain Syndromes Managing Pain during Pregnancy and Lactation Minor and Short-Acting Analgesics, Including Opioid Combination Products