Characterisation of new-onset chronic musculoskeletal pain in Long COVID

Abstract

New-onset chronic musculoskeletal (MSK) pain is a prevalent and debilitating symptom of Long COVID (LC) that impacts individuals’ quality of life. Understanding this novel pain is crucial for developing appropriate treatment approaches. The main aim of this research was to comprehensively explore the clinical characteristics, underlying pathophysiological mechanisms, and natural progression of new-onset chronic MSK pain in LC. A literature review was conducted to identify existing knowledge and research gaps regarding new-onset chronic MSK pain in LC. This review informed the study’s design, which focused on exploring detailed pain, the characteristics of the new-onset chronic pain, and tracking its progression over time. Cross-sectional data from the baseline timepoint indicated that new-onset chronic MSK pain is often widespread, constant, and associated with general weakness, functional reduction, depression, anxiety, and diminished quality of life, with underlying mechanisms of central sensitisation and pro-inflammatory state. Longitudinal data collected at multiple timepoints tracked the changes and progression of the novel pain syndrome over time, offering insights into its natural history and evolution. The data revealed that pain severity remained stable despite reduced inflammation levels over the study period, which could be attributed to prolonged early-stage inflammation that potentially sensitised the nervous system, leaving a residual effect of central sensitisation. Applying the American College of Rheumatology (ACR) criteria for Fibromyalgia Syndrome (FMS) revealed that 72.2% of assessed participants met the FMS criteria. This finding underscores the overlap between FMS and new-onset chronic MSK pain in LC and supports the hypothesis that FMS may develop as a long-term sequela of a viral infection, Studying MSK pain in LC also offers an opportunity to understand FMS symptoms, highlighting the need for further research into exploring the link between FMS and post-infection sequelae. In summary, this thesis provides new insights into the development of evolution of new-onset chronic MSK pain after COVID-19 infection. The findings will inform clinical practice, advance care and guide future research in this area.