Characterizing Fatigue Subtypes in Adolescents with Chronic Musculoskeletal Pain and Pain-Free Controls

Ian Boggero,1,2 Cecelia Valrie,3,4 Krystal Morgan,5 Nao Hagiwara,3 Susmita Kashikar-Zuck,2,6 Christopher King2,6 1Department of Oral Health Science, Division of Orofacial Pain, University of Kentucky College of Dentistry, Lexington, KY, USA; 2Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA; 3Department of Psychology, Virginia Commonwealth University, Richmond, VA, USA; 4Institute for Inclusion, Inquiry, and Innovation, Virginia Commonwealth University, Richmond, VA, USA; 5Division of Transplant, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; 6Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USACorrespondence: Ian Boggero, 740 S Limestone, Lexington, KY, 40536, USA, Tel +859-562-3291, Email ian.boggero@uky.eduContext: General fatigue, sleep-related fatigue, and cognitive fatigue are prevalent and disruptive in adults with chronic musculoskeletal (MSK) pain, but little is known about these fatigue subtypes in pediatric musculoskeletal pain.Objective: To compare fatigue and its subtypes between adolescents with chronic MSK pain and pain-free controls and to test if fatigue subtypes were associated with concurrent pain and its impact (pain intensity, number of pain sites, pain interference, and functional disability) or experimental pain (intensity and tolerance) in adolescents with chronic MSK pain. Finally, we sought to explore adolescents’ qualitative characterizations of their fatigue.Methods: Adolescents with chronic MSK pain (12– 17 y.o., n = 26) and pain-free controls (n = 26) completed validated self-report measures of fatigue, pain, and functional disability, underwent an experimental pain tolerance task (cold water immersion of the hand), and provided qualitative descriptions of their fatigue (pain group only).Results: Adolescents with chronic MSK pain reported significantly greater general, sleep-related, and cognitive fatigue than pain-free controls (all p’s < 0.001). In adolescents with chronic MSK pain, fatigue subtypes were associated with clinical pain and pain impact (r’s = 0.43– 0.84) but not experimental pain measures (p’s > 0.05). Adolescents with chronic MSK pain qualitatively described the negative implications of the different fatigue subtypes, particularly when perceived as long-lasting.Conclusion: This preliminary study suggests that fatigue subtypes are prevalent and impactful in pediatric patients with chronic MSK pain. When planning multi-disciplinary treatment for pediatric MSK pain, providers should recognize fatigue as another disabling symptom.Keywords: disability, fatigue, pediatric, musculoskeletal pain, widespread bodily pain