https://www.explorationpub.com/Journals/emd/Article/100780 Chronic pain, fibromyalgia, and long COVID Jürgen Braun * Open Access Review Explor Musculoskeletal Dis. 2025;3:100780 DOI: https://doi.org/10.37349/emd.2025.100780 Received: October 18, 2024 Accepted: December 18, 2024 Published: January 22, 2025 Academic Editor: Fernando Pérez-Ruiz, Cruces University Hospital, Spain Abstract Chronic pain is a common problem in rheumatology. A distinction is made between nociceptive pain and nociplastic pain. Nociceptive pain is, for example, mechanistically explained by persistent inflammation. Neuropathic pain is caused by nerve damage of various possible causes. In contrast, nociplastic pain is not due to tissue damage or a lesion in the somatosensory nervous system—at least not with the currently available techniques. Nociplastic pain is based on an altered perception of pain through modulation of stimulus processing. The concept of central sensitization, together with other neurobiological and psychosocial mechanisms, is considered to be the best explanation for such pain conditions. The syndrome of fibromyalgia (FM), considered to be due to central sensitization, plays a major role in rheumatology—both in terms of differential diagnosis and because the management of inflammatory rheumatic diseases can be made more difficult by the simultaneous presence of FM. During the coronavirus pandemic, persistent pain syndromes with similarities to FM were described following a COVID-19 infection. There is a growing scientific controversy as to whether the so-called long COVID syndrome (LCS) is a separate entity or just a variant of FM. Keywords SARS-CoV-2, COVID-19, central sensitization, nociplastic pain, neuropathic pain
Chronic fatigue syndrome CFS is primarily characterized by chronic fatigue which restricts activity levels, lasts for at least 6 months, and women are more frequently affected than men. The disease compromises the ability to perform daily activities, patients report feeling unwell after exertion and not sleeping restfully, they show either cognitive impairment or orthostatic intolerance, and physical disability may occur [21, 22]. In addition to fatigue, people affected by CFS suffer from neurocognitive, autonomic, and immunological symptoms. Post-exertional malaise (PEM), a pronounced and persistent intensification of all symptoms after minor physical or mental exertion, is particularly characteristic of the disease. This leads to pronounced weakness, diffuse muscle pain, flu-like symptoms, and a worsening of the general condition [21, 22]. CFS, FMS, LCS, silicone breast implant syndrome (SBI), sick building syndrome (SBS), post-orthostatic tachycardia syndrome (POTS), and adjuvant-induced autoimmune inflammatory syndrome (ASIA) are often associated with clinical symptoms characteristic of dysautonomia: severe fatigue, dizziness, fogginess, memory loss, dry mouth and eyes, hearing impairment, tachycardia [23].
