Juvenile Primary Fibromyalgia Syndrome 

Juvenile primary fibromyalgia syndrome (JPFS) is a musculoskeletal pain syndrome characterized by multiple discrete tender points (TPs), fatigue, and sleep disturbance in the child and adolescent. JPFS can be chronic in nature and can necessitate a multidisciplinary approach to the ongoing treatment of the disorder. The pain experienced is modulated by factors such as activity, anxiety, stress, and weather changes.

The diagnosis is made on the basis of the presence or absence of specific criteria that have been found to be consistent with those who experience JPFS (see Differentials). The chronic nature of fibromyalgia in the pediatric population suggests consequences for psychosocial development and implies a more difficult transition from childhood to adulthood.^[1]

The core feature of fibromyalgia is widespread musculoskeletal pain, with multiple TPs and other associated features (eg, fatigue, joint stiffness, skin tenderness, postexertional pain, sleep disturbance, irritable bowel symptoms, poor memory, tension headaches, dizziness, fluid retention, paraesthesias, restless legs, bruising, and Raynaud phenomenon). Chronic musculoskeletal pain affects quality of life, whereas fatigability influences motor response and ability to complete activities of daily living within an expedient time frame.^{[1, 2]}

The understanding of fibromyalgia syndrome (FMS) in children is still in its infancy stage; however, great strides have been made in both diagnosis and treatment in the past 10 years. Because the prevalence of FMS in children is increasing, diagnosing the disorder early in its course (see Clinical) and then recommending a multidisciplinary approach to treat the child’s disorder (see Treatment) are important. An approach that involves support for the family and specific recommendations for treatment may help decrease the symptomatology and increase the child’s functioning.

Go to Fibromyalgia and Rehabilitation and Fibromyalgia for complete information on these topics.

FMS is a physiologic entity rather than a psychiatric disorder. Yunus proposes a class of disorders called central sensitivity syndromes (CSSs), which result from changes in the central nervous system (CNS).^[3] Neurochemical pathology of the CNS (spinal cord and brain) causes areas of the body to become sensitized, so that pain is experienced from even mild touch or pressure.

Proposed members of the CSS family include the following^{[3, 4]} :

• Fibromyalgia syndrome
• Chronic fatigue syndrome
• Irritable bowel syndrome
• T-T headache (tension type)
• Migraine
• Temporomandibular disorders
• Myofascial pain syndrome
• Female urethral syndrome/interstitial cystitis
• Multiple chemical sensitivity syndrome
• Restless leg syndrome
• Periodic limb movements in sleep (PLMS)
• Primary dysmenorrhea
• Posttraumatic stress disorder

The underlying concept of the CSSs is that the 13 disorders have some similar clinical features and a common pathophysiologic component of central sensitization (CS). (See Etiology.) Yunus disputes the idea that the pain experienced by people with CSSs is merely psychiatric, psychosocial, or psychological in nature. Although depression and stress may contribute to the symptoms of CSS, they are still based on objective changes in the CNS.^[3]

The physiology of CS involves a process in which inflammation that may be caused by a minor trauma sets off an involved CNS response that results in pain and distress. The response pathway starts with the initial input that causes the release of bradykinin, prostaglandins, serotonin, and substance P to activate A-delta and C-fiber nociceptors at peripheral tissues.^[3]

Nociceptive impulses travel through fibers to wide-dynamic-range neurons in the spinal cord. At nerve terminals, activated C-fibers convey neurotransmitters or neuromodulators that generate a barrage of impulses at the synapse and hyperexcite postsynaptic receptors. The changes cause hyperexcitability escalation of other neurons, giving rise to hypersensitivity to peripheral stimuli.^[3]

The enhanced nociceptive (spinal) flexion reflex (NFR) is a consistent objective test for CS, obtained by electrically stimulating the sural nerve and then measuring the electromyelographic (EMG) response of the biceps femoris. People with fibromyalgia or other CSSs have demonstrated an accentuated NFR (or decreased stimulus threshold), which is indicative of CS.^[3]

Along with the CS response, other physiologic aspects of CSSs include sympathetic overactivity, genetic factors, neuroendocrine dysfunctions, peripheral nociception generators (eg arthritis), environmental stimuli, poor sleep, viral or local infections (may trigger inflammatory mediators that activate nociceptive fibers), nonrestorative sleep, and psychosocial distress.^{[3, 4]}

United States statistics

Estimates of the prevalence of JPFS using the American College of Rheumatology (ACR) diagnostic criteria (see Differentials) are as high as 6%.^[1] JPFS accounts for 7.7% of new diagnoses made among children and adolescents by pediatric rheumatologists. Musculoskeletal pain syndromes, which include JPFS, account for approximately 25% of new referrals to pediatric rheumatologists. JPFS is the diagnosis in 25-40% of children with musculoskeletal pain syndromes.^[1]

In the United States, FMS affects approximately 2% of the population.^[3] Earlier data for the adult population indicated that 0.5% of men and about 3.4% of women are diagnosed with FMS.^[5]

Romano studied 15 children (10 females, 5 males) aged 16 years and younger (mean age, 13 y) in a rheumatology clinic and found that many cases of juvenile FMS go undiagnosed and are confused with other diagnoses.^[6] He reported that 67% visited 3 or more doctors before evaluation by a rheumatologist; 60% were diagnosed with juvenile chronic arthritis, and other misdiagnoses included psychological problems, hysteria, and growing pains.^[6]

International statistics

Fibromyalgia syndrome occurs in 6.2% of Israeli school children^[7] and 1.3% of Mexican school children.^[8]

Age-related differences in incidence

Patients with pediatric FMS most frequently present in adolescence (age 13-15 y). The mean age of onset is 12 years. The earliest reported case in pediatrics was a 5-year-old child with FMS.

Sex-related differences in incidence

FMS is diagnosed more commonly in girls than in boys (at least 3-7 times more commonly). Most children diagnosed with JPFS are prepubertal or adolescent girls aged 13-15 years,^{[9, 10]} although boys of the same age or younger have also been diagnosed; reported figures indicate as many as 35% of all children diagnosed with the syndrome are boys.

Race-related differences in incidence

In the United States, FMS is less common among black children.

Improvement in signs and symptoms of FMS is likely in children and adolescents.

In 1995, Buskila and colleagues studied FMS among children aged 9-15 years.^[11] Data on 15 of the children showed that 73% (ie, 11 of the 15) no longer met criteria for FMS (see Differentials) at 30 months’ follow-up. The mean number of TPs and the amount of force necessary to elicit pain at each TP showed significant improvement.

Symptoms among the 4 children who still met criteria for FMS included abdominal pain, headache, paresthesias, morning stiffness, and sleep disturbance. Additionally, 7 children were observed who did not progress to the point of meeting the full criteria over the 30 months, and all 7 children had improved.

In 1998, Siegel and colleagues observed 33 patients, with a mean follow-up of 2.6 years. Improvement was observed in most patients during that follow-up time, with all patients showing some positive response to treatment.^[10] Given prognostic findings, children with FMS as a whole are more likely to have a favorable outcome than adults diagnosed with FMS.

In 2000, Gedalia and colleagues, after observing children in a rheumatology clinic, collected data on 50 children with an average follow-up period of 18 months.^[12] They found that as compared with the initial presentation, 60% of the children had improved, 36% had stayed the same, and 4% had worsened. Nearly all of the children needed to continue medications for up to 4 years after initial presentation.

Health care providers are responsible for educating children and families about every facet of FMS in an effort to improve basic knowledge and coping mechanisms to deal with the long-term aspects of the disease.

All individuals involved must have fully understand the goals of treatment, including exercise regimes, expectations of medication therapy, and overriding aspects of living with chronic pain. Successful treatment and improved outcomes are enhanced when the patient has a multifaceted approach to treatment, including medical care, psychologic interventions, and physical therapy. Education concerning every aspect of care and intervention is a key to successful treatment of FMS.

For patient education resources, see the following:

Muscle Disorders Center

Mental Health and Behavior Center

Back, Ribs, Neck, and Head Center

Fibromyalgia

Chronic Fatigue Syndrome

Chronic Pain

Fatigue