The spectrum of pediatric amplified musculoskeletal pain syndrome

Abstract

Background Children presenting with musculoskeletal pain to pediatric rheumatology clinics are very heterogeneous and on a continuum from those with localized pain to total body pain. Many report intermittent, rather than constant, pain. We examined clinical and psychological characteristics of these children at presentation and specifically those who fulfilled the criteria for fibromyalgia. Methods We performed a retrospective, cross-sectional cohort study of children under ≤18 years old presenting to the pediatric rheumatology pain clinic between January 2015 and July 2019 and enrolled in a patient registry. We included children diagnosed with amplified pain, excluding those fulfilling criteria for complex regional pain syndrome. Abstracted data included clinical characteristics, pain symptoms, functional disability inventory (FDI), widespread pain index, and symptom severity scale. Results We analyzed 636 subjects, predominantly non-Hispanic Caucasian females. Using median split method, 54% had diffuse pain (≥ 5 body regions involved), but, of these, only 58% met criteria for fibromyalgia. Subjects with diffuse pain, compared to those with localized pain had a longer duration of pain (24 vs 12 months, p < 0.01), reported greater pain intensity (6/10 vs 5/10, p < 0.001), greater mental health burden, and poorer function (FDI 25 vs 19, p < 0.0001). Subjects with limited pain more often reported a history of trigger event (34% vs 24%, p < 0.01) but not autonomic changes (14% vs 14%, p = 0.94). The presence of adverse childhood experiences did not differ among those with limited versus diffuse pain except for parental divorce (16% vs 23%, p = 0.03). Intermittent pain was reported in 117 children (18%) and, compared to subjects with constant pain, they reported less pain (0/10 vs 6/10) and were more functional (FDI 13 vs 25) (both p < 0.0001). Conclusions There exists a wide spectrum of pain manifestations among children with amplified pain including limited or diffuse and constant or intermittent pain. Most children who presented to our clinic did not fulfill criteria for fibromyalgia but nonetheless had significant symptoms and disability. Studies focusing on fibromyalgia may miss the full extent of childhood amplified pain. Additionally, research limited to those meeting the fibromyalgia criteria likely underestimate the significant impact of amplified pain among the pediatric population.

Amplified Pain Syndrome—An Insupportable Assumption

“…1(p2) Currently, there is no agreement as to causative mechanism, pathogenesis, or even the criteria used for the diagnosis of these conditions. 1 Notwithstanding these major nosological and epistemological deficiencies, APS seems to have been accepted into the taxonomy of pediatric pain medicine. 1 In this Viewpoint, our aim is to show that APS is a flawed construct that has the potential to stigmatize children presenting with severe and disabling pain.…”

Recognizing medical child abuse in children presenting with chronic pain

“…8 The pain can be constant or intermittent, localized or widespread and the pain cannot be attributable to a known underlying cause. 9 The diagnosis of intermittent amplified pain is usually made on history alone since the child typically does not have a pain episode during the medical appointment. The treatment is daily intense occupational and physical therapy, along with cognitive behavioral therapy, which restores the vast majority of these children to normal function and frequently the total resolution of pain.…”

“…These children are generally younger; our mean patient age was 7 years and the average age of our population of children with amplified pain is 13 years. 9 Children with MCA generally have multiple non-pain related diagnoses and have had multiple procedures at the insistence of the parent. The diagnoses reported do not correspond to the findings and the history varies on the situation or provider.…”

Amplified Pain—A Helpful Diagnosis

“…Using a sympathetically mediated model of pain amplification is helpful as it reinforces that a real pain signal is amplified. 1 If one were to prick one's finger, the pain is real but, in these cases, the body then shuts down blood flow to the area, which, like having a rubber band on your finger too long, causes pain. This new signal is again fed into a vicious cycle leading to more pain.…”

“…This is especially trueofthosewithintermittentpainwhoareexcludedfrom most classification criteria. 2 The sympathetically mediated model many pediatric rheumatologists use to explain how abodilysignalisamplifiedtocauseseverepainmakesittangible, understandable to a child, and validates their pain. 1 Many of these children are accused of faking or looking for attention, they are relieved to know that their pain experience is real, that there is a reason for the intensity of the pain, and they have a name fortheirpaintheycanuseandunderstand.Indeed,multiplecentersthat seethesechildrenusethistermsuchasClevelandClinic,JohnsHopkins, andUniversityofCalifornia,SanFranciscoasdoestheAmericanCollege of Rheumatology.…”