Children may experience a variety of recurrent chronic pain, such as headache or abdominal pain. Chronic pain is more common in children than persistent pain and is less likely to be associated with underlying organic disease. Some common conditions that may turn chronic pain into persistent pain include rheumatoid arthritis, malignancies, sickle-cell disease (SCD), and neuropathic pain syndromes.

The management of chronic pain is an important part of pediatric practice. It requires an understanding of pediatric illnesses as well as the psychosocial aspects of chronic pain conditions experienced by children. Most of the pediatric pain and related problems are undertreated. Because of the complex nature of chronic pain, treatment is often approached from a broad-based, comprehensive medical model that utilizes the expertise of psychologists, neurologists, anesthesiologists, nurses, and other health care providers (HCPs). This chapter evaluates some common types of recurrent and persistent pain in infants and children and summarizes treatment strategies, including pharmacologic and nonpharmacologic therapies.

Recurrent headaches are an exceedingly common form of recurrent pain in pediatric patients. The most common types of headaches children experience include migraine, tension headache, and combined migraine-tension headache. Up to 10% of all children experience recurrent headaches.¹ The prevalence of nonmigrainous headache in childhood and adolescence is 10% to 25%.² Migraine headaches are more commonly experienced by boys than girls in early childhood but become more common in girls upon reaching puberty. There is usually a strong family history of migraine headaches. Children typically report an abrupt onset of unilateral or bilateral severe, throbbing headache pain, which is often associated with nausea and vomiting. Although some children experience classic visual or auditory auras of migraine, many experience more subtle premonitory signs such as pallor, irritability, and fatigue.³ Patients typically experience relief after sleep. Tension headaches are most common among adolescents. Typically, there is no associated aura, nausea, or vomiting. These headaches are usually described as a squeezing pain located circumferentially around the head. It is not uncommon for patients with tension headaches to experience them daily. Children with combined headaches experience both chronic tension headache and episodic acute migraine headache and their associated abdominal pain, nausea, and vomiting. The diagnosis of chronic daily headache is made when headache has been present for more than 15 days per month, with a duration of 3 months or longer.

Chronic progressive headache is most likely the result of a secondary etiology, such as changes in intracranial pressure, infection, or neoplasm.⁴

Most headaches in children are not associated with serious underlying intracranial pathology or organic disease. A thorough history and physical examination are essential and should include a careful neurologic with funduscopic examination. A psychosocial history is also beneficial in helping to determine whether family stressors or maladaptive behaviors might play a causative role in reinforcing pain behaviors. A history of personality changes, visual disturbances, fever, and headaches associated with neurologic deficits are signs that neuroimaging is indicated. Chronic progressive headache or focal symptoms on neurologic examination warrant neuroimaging to investigate for structural abnormalities or malignancies. The routine use of diagnostic studies is not indicated when the clinical history reveals no associated risk factors and the child’s examination is normal.⁵

Treatment for headaches in children includes the use of both pharmacologic and nonpharmacologic therapies. Patient and family education should be provided, along with reassurance that a most worrisome cause of headaches is unlikely and that reevaluation will be ongoing. Often, a diary will be kept by the patient, documenting the characteristics of the headaches, medications tried, diet, and stress level at the time of onset to identify aggravating factors. Modifications or any disruptions to the patient’s lifestyle such as increasing physical activity as the patient can tolerate it, improving school attendance, and restoring sleep hygiene are important. In addition, cognitive-behavioral interventions can alleviate headache pain and promote functional and adaptive behavior.

Combinations of analgesics, antiemetics, and 5-HT serotonin agonists are commonly used abortive migraine therapies for children. Nonsteroidal anti-inflammatory drugs (NSAIDs) are often first-line agents for migraines, tension headaches, and combined headaches.⁶ Patients should be instructed about proper dosing, as excessive use of NSAIDs, acetaminophen, and combination drugs such as Fioricet can cause rebound headaches.⁷ Systematic reviews of NSAIDs among adult patients report little difference in their clinical effectiveness. However, parenteral NSAIDs such as ketorolac are often used in patients with persistent vomiting who cannot tolerate oral intake. In a randomized crossover study, ibuprofen was found to be more effective than acetaminophen for interruptive therapy.⁷ Ibuprofen in suspension form is commonly used for abortive headache therapy in children who are unable to swallow pills. The recommended pediatric doses are between 6 and 10 mg/kg, taken orally. The 5-HT serotonin agonists, such as sumatriptan, zolmitriptan, and rizatriptan, have been shown to be effective abortive therapies in patients with severe migraines.^8–10 Chronic opioid use is generally not recommended for the treatment of recurrent or chronic headaches.¹¹

Antidepressants, beta-blockers, and anticonvulsants are frequently used for prophylactic migraine therapy. Low-dose tricyclic antidepressants, such as amitriptyline and nortriptyline, may provide effective migraine prophylaxis. Typical starting dose in children is 0.2 mg/kg, administered at bedtime, to promote improved sleep. The doses are titrated, based on the clinical response and any side effects the patient may experience. Trazodone has been shown to be more effective than placebo in a crossover trial but should be avoided in teenaged boys because of the potential for priapism.¹² Propranolol is often used in doses of 1 to 2 mg/kg daily; however, controlled studies in pediatric headache management have shown equivocal results.^13,14 Gabapentin 5 to 10 mg/kg/day, with a maximum dose of 2400 to 3600 mg, is commonly prescribed for patients with chronic headache. Several studies have shown positive clinical results from treatment with calcium channel blockers. Coenzyme Q10 supplement 25 to 300 mg/day can be effective in the prevention of migraine.¹⁵ Occipital nerve blocks and botulinum toxin injection can control some intractable headaches.

Nonpharmacologic therapies and treatments for chronic headache in children include cognitive-behavioral therapy, biofeedback, relaxation, guided imagery, self-hypnosis, family therapy, and acupuncture. Evidence supports the effectiveness of biobehavioral headache management, when compared to pharmacologic agents, for certain types of headaches in children.^14,16 Through biofeedback, guided imagery, and progressive muscle relaxation, patients learn to shift their cognitive focus away from the pain, thereby decreasing their experience of pain. These skills reduce stress and anxiety, which are precipitating factors in many children with headaches. Cognitive-behavioral strategies help patients improve coping skills, return to school, recognize maladaptive behaviors, and reinforce more functional lifestyles. Acupuncture may be a valuable tool for patients with frequent, episodic, or chronic tension-type headaches.¹⁷ Available studies suggest that acupuncture is at least as effective as, or possibly more effective than, prophylactic drug treatment and has fewer adverse effects.¹⁸

Chest pain in children and adolescents is a common presenting symptom in emergency rooms, general pediatric practices, and pediatric pain clinics. Because chest pain is often an ominous symptom among adults, it causes much distress to children and their parents. It is, however, not commonly associated with heart disease in children. Of 67 patients referred to a pediatric cardiology clinic with chest pain, only 6% were found to have underlying cardiac disease.¹⁹ The most common causes of chest pain in children include costochondritis, idiopathic causes, muscle pain from coughing, and other musculoskeletal causes.^20,21 Additional causes of chest pain in children include slipping rib syndrome and abdominal and gastroesophageal disease.²²

A thorough medical history and physical examination help identify cardiac symptoms. Selbst and colleagues found that organic causes of chest pain in children were more common when associated with abnormal findings on physical examination or when symptoms were present in a younger child.²⁰ A history of syncope, presyncopal episodes, or a history of palpitations warrants further evaluation. Gastroesophageal reflux or esophageal spasm may cause referred pain in the chest.

In the absence of worrisome findings on history or physical examination, education and reassurance that heart disease is not a likely cause for the pain are helpful in resolving the symptoms in the long term.^19,23 A trial of NSAIDs may be helpful for patients with musculoskeletal causes such as costochondritis. Nonpharmacologic therapies such as physical therapy, transcutaneous electrical nerve stimulation (TENS), heat, and relaxation therapies are helpful for many pediatric patients experiencing chest pain.

Abdominal pain is a common painful condition in infants, children, and adolescents. Functional abdominal pain (FAP) is recurrent episodic pain with no evidence of structural or inflammatory origin.²⁴ It is a common condition among school-aged children. Several studies report that up to 25% of school-aged children experience recurrent abdominal pain, with the highest prevalence among girls.²⁵ Many children with FAP can maintain normal activities; the patients seen at pediatric pain clinics are typically those with more severe patterns of pain and disability. In most cases, there is no clear identifiable cause of FAP in school-aged children.^25,26

A number of clinical characteristics distinguish benign FAP from other types of childhood abdominal pain. In general, children with FAP are between 4 and 16 years of age, experience episodic abdominal pain interspersed with pain-free periods, and are otherwise thriving and medically well. Children with FAP frequently describe diffuse periumbilical pain that is poorly localized. It rarely radiates to the back or chest. Pain is often worse at night but rarely awakens the child from sleep. Many children experience other chronic symptoms, such as headaches, nausea, and dizziness.

In the majority of cases, FAP is functional, which refers to the lack of an identifiable biochemical, structural, or other organic cause. However, the lack of a readily identifiable cause does not imply psychogenic origin. Most children with FAP are generally medically and psychologically well.²⁷ A subgroup of patients will have a recognizable underlying disease, such as lactose intolerance, constipation, ureteropelvic junction obstruction, inflammatory bowel disease, or endometriosis.^28–32 For many children, however, an underlying etiology is not diagnosed. Some studies suggest that FAP may be a precursor to irritable bowel syndrome (IBS) in adults, and that some children and adolescents may progress to meet the standardized criteria for IBS as adults.^33,34 In a study of 200 children with recurrent abdominal pain, somatic causes were found in 26%. Laxative therapy was successful in 46%, resulting in nearly all patients with functional abdominal pain becoming pain free. Eventually, 99% became pain free using a therapeutic intervention protocol.³⁵

The diagnosis of FAP should be based on thorough history, physical examination, and review of symptoms. A psychosocial history is essential to learn how the child and family cope with pain and to identify issues, such as school avoidance and reinforcers of pain. A history of fever, weight loss, growth failure, rash, or other symptoms of systemic illness should prompt further investigation of organic causes.^36,37 Occurrence of persistent pain or recurrent abdominal pain in children younger than 4 years of age is also of concern. Physical examination should include a rectal examination with stool guaiac, evaluation for undescended testes, hernias, and abdominal masses. Findings on history and physical examination suggesting a possible underlying organic disorder should serve as a guide to laboratory and diagnostic testing. In general, extensive routine screening tests such as endoscopies, barium studies, and other radiographic studies are of low yield, particularly when there are no specific clinical suspicions from history or physical examination. In addition to careful history and physical examination, baseline complete blood count, sedimentation rate, and urinalysis are reasonable screening tests to help rule out occult organic disease. A family history of inflammatory bowel disease in a child with chronic abdominal pain warrants further laboratory and possibly diagnostic testing. In children who experience chronic persistent abdominal pain rather than the more characteristic episodic pain of FAP, laparoscopy identifies treatable conditions in a high percentage of cases.^38,39 In a study of 104 children with FAP, parents were randomly assigned and trained to interact with their children according to one of three conditions: attention, distraction, or no instruction. Parents of the pain patients rated distraction as having greater negative impact on their children than attention.⁴⁰

A significant component of treatment is education and reassurance that no serious organic illness is likely. It should be emphasized that the child’s pain is genuine and that clinical reassessments will be ongoing. Treatment is based on improving function and reducing maladaptive pain behaviors through emphasis on cognitive-behavioral therapies.^41–44 Underlying anxiety or depression should also be addressed. A return to school and participation in normal family and social activities is essential. Extensive diagnostic testing and referrals to multiple subspecialists may heighten patient and parental anxiety and reinforce a patient’s “sick role.” Although the study indicated no significant difference between amitriptyline and placebo after 4 weeks of treatment,⁴⁵ tricyclic antidepressants are commonly used. Antispasmodics are sometimes used; however, there are limited data on the efficacy of drug therapy. The routine use of pain medications should be avoided. Hypnotherapy can be used for children with FAP.⁴⁶

Longitudinal studies show that only 30% of children with FAP have resolution of pain within 5 years and 25% to 50% continue to experience symptoms as adults. Walker and colleagues found that in a 5-year follow-up, only 1 in 31 children with FAP was eventually diagnosed with a definable “organic” disease.⁴⁷ A meta-analysis of 10 controlled studies regarding the effectiveness of psychological therapies for pain reduction in children with recurrent abdominal pain showed that psychological therapies are effective in treating children with chronic abdominal pain.⁴⁸

Endometriosis is a common cause of pelvic pain among adolescents, affecting 45% to 70% of adolescents with chronic pelvic pain.^49,50 In general, endometriosis affects women of reproductive age, but adolescent girls can experience pain from endometriosis prior to the onset of menses. Laufer and colleagues studied adolescent patients with chronic pelvic pain which was unresponsive to conservative medical treatment using oral contraceptives and NSAIDs and determined that 70% of patients had endometriosis upon diagnostic laparoscopy.⁴⁹ A variety of other medical conditions such as painful musculoskeletal disorders, constipation, urologic conditions, and irritable bowel syndrome may present as chronic pelvic or abdominal pain.

Many adolescent patients with endometriosis report both cyclic and acyclic pelvic pain. Some patients experience more severe pain at midcycle and with menstruation, but many will experience pain throughout the month. There is evidence to suggest that the severity of endometriosis seen on laparoscopy does not necessarily correlate with the severity of pain.⁵¹