Diagnosis and Management of Pediatric Amplified Musculoskeletal Pain
OCTOBER 13, 2014
Julian Kaye, PhD
Affected children show a wide variety of amplified musculoskeletal pain syndromes (AMPS) that may or may not be associated with overt autonomic signs and may be diffuse or localized to one body part. It is most common in pre- to adolescent girls. Hallmarks of the diagnosis include increasing pain over time, allodynia, an incongruent affect, disproportional dysfunction, and the absence of other causes.
At the 2014 AAP National Conference & Exhibition, Cara Hoffart, DO, presented a session intended to guide practitioners on how to effectively discuss pathophysiology and treatment strategies for amplified pain with patients and prescribe a treatment approach that does not require drug therapy for pain or sleep aids.
Hoffart, the Medical Director of the Rehabilitation for Amplified Pain Syndromes Program in the Divisions of Rheumatology and Pain Management at Children’s Mercy Hospital, Kansas City, MO, briefly reviewed the spectrum of overlapping manifestations of these disorders which come under a variety of labels, including fibromyalgia and complex regional pain syndrome (CRPS) or “Cold Blue Foot.”
Hoffart prefers to avoid the term fibromyalgia – the “F” word, especially with her patients, due to the stigma attached to it and the potential for prejudicing the prognosis and outcome of treatment. Furthermore, Internet searches using this term can expose the patient and her family to disinformation and quack treatments. There is an opportunity to intercept the progression of these disorders in children. Effective intervention becomes increasingly difficult in adulthood.
In her clinic, Hoffart sees a tremendous phenotypic variability. The prevalence of juvenile primary fibromyalgia syndrome (JPFS) is as high as 6%. The average age of onset is 12-13 years and anxiety or major depression reaches 50% in children but is lower in adult AMPS. Affected children are mainly female (80%) and Caucasian (80%).
Possible etiologies are unclear. A complex biopsychosocial model postulates that injury or illness resulting in pain and immobilization engenders a fear of movement and activity, loss of fitness and sleep disturbance which can exacerbate the pain. This leads to a vicious cycle of fatigue, poor school attendance and loss of social contacts which promotes psychological stress which can further amplifies the pain. Pain can arise directly from psychological stress or be idiopathic.
Pathophysiology may relate to lactic acid metabolism, involvement of the sympathetic nervous system and changes to the brain architecture. The two parallel somatosensory pathways are believed to converge in AMPS with the induction of central sensitization.
The therapist must assure the patient that he or she recognizes that their pain is real, that it is understandable, and that the patient is not faking it (ie, the pain is not “all in your head”). Hoffart said that some patients burst into tears when they finally encounter an empathic practitioner.
The work up includes past medical history, social history, physical examination, autonomic signs, tests for allodynia and hyperalgesia and laboratory tests and imaging to exclude a physical cause. Hoffart stressed the importance of evaluating the ESR. A value greater than 70 mm/hr might signify a thrombus.
Conversion should be considered as a possible comorbidity. Hoffart said that, in her experience, conversion can even be transmitted from one patient to another. Other challenges in management include overcoming the patterns of complex and controversial treatment regimens such as the use of opioids, anticonvulsants, antidepressants, spinal cord stimulation and even surgical interventions.
The complex biopsychosocial model requires an intensive multidisciplinary approach incorporating a definitive diagnosis and plan, complete cessation of medical investigations and pain medications, an aggressive exercise regimen, desensitization procedures for allodynia and hyperalgesia (the “torture chamber”), counseling and/or stress management, obligatory school attendance and participation in other functional activities. The programs at Children’s Mercy Hospital, Kansas City are typically of 3-4 weeks duration.
Throughout her presentation, Hoffart showed very moving photographs and videos of her patients chronicling their progress with therapy. The comparisons before and after strenuous exercise routines were especially remarkable. The treatment plans for these AMPS patients should also cope with relapses.