Chronic Pain

44 Chronic Pain




THE PRACTICING PEDIATRIC ANESTHESIOLOGIST sees chronic pain in one of three main venues: a child coming to the operating room for a procedure, after a request for a consultation from a colleague of another specialty, or when making acute pain management rounds. In this chapter, we focus on the essential approaches to children with chronic pain and provide guidelines to help the children and colleagues who request your assistance.



Chronic Pain in Children


Chronic pain affects a large number of children.1 Back pain has been reported in up to 50% of children by the mid-teens,2 and abdominal pain occurs weekly in up to 17%.3 Other conditions such as headaches, complex regional pain syndrome (CRPS), fibromyalgia, limb pain, chest pain, and joint pain are common and affect quality of life.47


Several chronic medical conditions are strongly associated with pain and blur the boundaries between acute and chronic pain treatment, including sickle cell disease, cystic fibrosis,8 epidermolysis bullosa,9 and cancer. These children require frequent hospitalizations, and their pain can be severe. Because the children present with pain in the hospital, treatment often follows the model for acute pain management based on medication use. However, psychosocial factors heavily influence the child’s ability to cope and can improve or worsen the child’s suffering, depending on personal and family factors.10,11 It is appropriate to seek psychology, child life, and physical therapy consultations as part of the therapeutic plan. The ultimate goal for each of these medical conditions is to stabilize the child’s condition and return her or him home. For many, the painful disease and dysfunction continue, and having a long-term plan that is integrated with acute management is vital.



Multidisciplinary Approach


The model of care that appears to work optimally for children with chronic pain is one in which multiple disciplines are involved in developing a coordinated care plan.4,12 In the outpatient setting, there is a pain physician, a psychologist, nurses, and a physical therapist. Sometimes, a neurologist or physiatrist may be involved. Anesthesiologists managing children with chronic pain should make use of these disciplines when recommending a plan of care. Advocating for the involvement of other therapeutic specialties can advance the patient’s care beyond suggesting a regional block or medication.





The Physical Therapist


Physical therapy is a crucial component of evaluating and treating chronic pain. The painful condition can cause loss of muscle strength and range of motion. Alterations in the use of a limb affect the biomechanics and daily function of the body. Children can become deconditioned and require a conditioning program to regain lost strength and stamina. These changes affect the original pain site and generate secondary pain problems that need to be addressed.


Physical therapy can benefit many painful conditions (e.g., myofascial pain improves with stretching and range-of-motion exercises) and is the cornerstone of treatment for others (e.g., chronic regional pain syndromes [CRPS]).14 Emphasizing self-reliance and responsibility for their own care is an important aspect of caring for adolescents. However, young children and older ones in pain cannot be expected to work aggressively at home without beginning with a structured program. Parental involvement is especially important for younger children, but the caretakers must be taught to be encouraging and supportive while not making them the child’s taskmasters.


Therapies provided by physical therapy include stretching, strengthening, and reconditioning programs. Range-of-motion exercises and endurance training are also important. Aquatic therapy is very useful for children who cannot bear weight on lower limbs or have limited range of motion or strength. Massage, heat, and cold therapies are helpful adjuncts to increase functioning and enhance other physical therapy modalities.


Transcutaneous electrical nerve stimulation (TENS) is an effective,15 low-risk, analgesic therapy that is usually provided under the guidance of a physical therapist. TENS is excellent for localized pain. The fact that it is portable, can be used discreetly, and has few side effects makes it attractive for use at school. Because tolerance to TENS can develop with prolonged use, children need to limit use to no longer than 2 hours at a time. They can take a break for an amount of time equal to the TENS use and then restart it.





General Approach to Management


Most children with chronic, noncancer pain are adolescents who require special considerations in terms of their history and physical examination. Because they are between childhood and adulthood, their behavior can fluctuate broadly and often. It is important to address them directly but also involve the parents to the extent needed to obtain the relevant and complete history. The clinician should not try to be “cool” with the adolescent patient, because teenagers tend to find that approach condescending and will respond negatively. The examiner should instead find a point of common interest and use it to establish greater rapport.


Adolescents tend to be very image conscious. They may or may not want to discuss body functions such as defecation or menstruation, even when these functions are directly relevant to the problem. If patients seem uneasy with the questions, the physician should proceed in a straightforward manner, acknowledge their feelings, and reassure them that the information is needed to help them. When discussing these pediatric patients with parents, clinicians should use a phrase such as “children and young adults” rather than just “children” because even 12 and 13-year-olds like to think they are no longer children.



History


The basic history focuses on the pain: location, duration, quality, intensity, aggravating and alleviating factors, associated symptoms, therapies that have been tried, and which tests have been performed and by whom. Pain intensity is often assessed by a 0 to 10 numeric rating scale for children older than approximately 8 years of age. The child must be asked about the current pain level and about the best and worst pain levels to obtain an idea of the pattern of pain and when it peaks. Quality descriptors include burning, sharp, aching, throbbing, tingling, numb, weird, and others; each may give a clue about the type of pain the child is experiencing. Odd descriptors, burning, and tingling suggest neuropathic pain; sharp, tight, and aching may indicate bony or muscular causes; throbbing suggests a vascular component; cramping or pain that comes in waves often suggests spasms of a muscle or hollow viscus.


A vital part of the chronic pain evaluation process is to look for red flags, which are signs or symptoms that may indicate a serious illness. Some of the red flag signs and symptoms for major pain types can be found in Tables 44-1, 44-2, and 44-3. For example, a child with back pain who also has weak legs and incontinence may have a tethered spinal cord. Headache that is worse in the morning and associated with vomiting suggests increased intracranial pressure. Back pain with loss of ankle jerk suggests compression of the S1 nerve root.


TABLE 44-1 Red Flag Signs and Symptoms for Abdominal Pain



TABLE 44-2 Red Flag Signs and Symptoms for Secondary Headache



TABLE 44-3 Red Flag Signs and Symptoms for Back Pain



A complete pain evaluation comprises further history regarding medications, allergies, family history, and a thorough review of systems. Certain painful conditions, such as migraine headaches,16 fibromyalgia,17 irritable bowel syndrome,18 and sickle cell disease, have a genetic basis. Knowing the family history can assist in making the diagnosis. The child sometimes may model his or her behavior after a family member. For example, if a parent has a “bad back” and is functionally compromised, the child also may complain of back pain. This does not mean the child is faking the complaints but simply patterning the behavioral response to pain after a model that he or she understands. Treatment can include reassurance, cognitive behavioral therapy, and gentle physical therapy to restore the child’s functional ability and help him or her with any underlying issues. Family and social histories can be useful in fashioning a treatment plan in conjunction with the general history, physical examination, and relevant testing.





Chronic Pain Conditions


Any part of the body can hurt, but in practical terms, several diagnostic clusters represent most pediatric pain conditions. The frequency and intensity of the pain can be striking. One study on the 3-month prevalence, characteristics, consequences, and provoking factors of chronic pain described the experience of 749 children and adolescents in one elementary and two secondary schools19: 83% experienced pain during the preceding 3 months. The leading sources of pain were headaches (60.5%, also perceived as most bothersome), abdominal pain (43.3%), extremity pain (33.6%), and back pain (30.2%). Many subjects reported associated sleep problems, restriction in hobbies, and eating problems. School absenteeism reached 48.8% in the population with pain. The use of health care resources by children and adolescents with pain was extensive: 50.9% visited the physician’s office, and 51.5% reported use of pain medication.



Abdominal Pain


Abdominal pain is a major source of distress in children that causes anxiety and invites a large amount of testing. This painful condition, formerly referred to as recurrent abdominal pain, is now described as functional gastrointestinal disorders (FGIDs).20 Specific criteria exist for the major categories so that FGIDs are no longer considered diagnoses of exclusion. The pain is thought to be caused by abnormal interactions between the enteric nervous system and central nervous system.21 Research suggests that peripheral sensitization and abnormal central processing of afferent signals at the level of the central nervous system play roles in the pathophysiology of visceral hyperalgesia—a decreased threshold for pain in response to changes in intraluminal pressure.22 The history and physical examination focus on excluding warning signs and symptoms of underlying disease (see Table 44-1).20,23 The role for testing, endoscopy, and radiographic evaluation is limited.


Multidisciplinary treatment of FGIDs includes medication, psychological interventions, and education, which often need to be ongoing. The most important aspect of the treatment plan is to establish realistic goals, which frequently means return of function rather than complete elimination of pain. Although the literature for treatment is sparse, tricyclic antidepressants such as amitriptyline, nortriptyline, or doxepin have been used effectively for FGID-related pain. Anticonvulsants also are useful because they modify nerve conductivity and transmission. Antacids, antispasmodic agents, smooth muscle relaxants, laxatives, and antidiarrheal agents can be added to address symptoms. Data support the use of peppermint oil capsules in managing irritable bowel syndrome, although gastroesophageal reflux can be a limiting adverse effect.24 Children with functional bowel disorders can have abnormal bowel reactions to physiologic stimuli, noxious stressful stimuli, or psychological stimuli (e.g., parental separation, anxiety). Children benefit from cognitive- behavioral therapy, coping skill development, biofeedback, hypnosis, and relaxation techniques (Table 44-4).25,26


TABLE 44-4 Care Pathway for Abdominal Pain




Headache


Headaches can be categorized as primary or secondary. Primary headaches include migraine, tension, cluster, and trigeminal neuralgia headaches. Secondary headaches are those attributable to head and neck traumas; muscle spasms; vascular disorders; nonvascular intracranial disorders; infection; eye, ear, cranium, nose, sinus, and teeth or mouth diseases; homeostatic disturbances; and psychiatric disorders. Headaches represent one of the more poorly tolerated types of chronic pain, with greater medication use than for other types. Of 77 children with long-term headaches who were followed up to 20 years after the initial diagnosis, 27% were headache free, and 66% had improved.27


Migraines (especially migraine without aura) and tension-type headaches are the most common types of pediatric headaches. The prevalence of migraine ranges from 2.7% to 10%. It occurs more frequently in boys than girls between 4 and 7 years of age, and then the prevalence equalizes between 7 and 11 years of age. After 11 years of age, three times more girls than boys have migraines.28,29 Studies are not routinely recommended in the absence of focal neurologic findings. However, the practitioner must be alert to red flag signs and symptoms that warrant imaging and laboratory studies to rule out an underlying condition as a cause of the headaches (see Table 44-2).


There is a genetic component to migraine and chronic tension headaches; 50% to 77% of children with migraines have a positive family history for migraine headaches, especially on the maternal side. The clearest genetic link has been established for familial hemiplegic migraine.16


Children with frequent headaches often suffer from medication overuse headaches due to chronic or repeated use of over-the-counter analgesics. If possible, children should be weaned off analgesics gradually.


Treatments for migraine and tension-type headaches overlap greatly. Pharmacologic interventions can be divided in two types. In the first, abortive treatment focuses on stopping the acute headache. In the second, prophylactic therapy is indicated for patients with more than two headaches per month, for children with severe attacks, and for those with frequent headaches unresponsive to medication (Table 44-5).30


TABLE 44-5 Care Pathway for Headaches



Older medications that have been used successfully to prevent headaches in adolescents include amitriptyline and trazodone. These medications tend to make children drowsy and are prescribed 30 to 60 minutes before bedtime each night. Younger children appear to respond well to the antihistamine cyproheptadine. Overall, few evidence-based recommendations can be made; the lack of randomized, controlled pediatric trials precludes an evidence-based recommendation.31 However, the anticonvulsant topiramate is a promising medication for the prevention of migraine headaches.3234


May 25, 2016 | Posted by in ANESTHESIA | Comments Off on Chronic Pain

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