Mechanisms of myofascial pain in the context of metabolism, redox stress and inflammation: a narrative review

Pain syndromes usually progress spatially in a stepwise fashion. Myofascial trigger points, a best-studied feature of myofascial pain syndrome and a very common finding on clinical examination of people with various chronic pain syndromes, occur in an active or latent form, consistent with the clinical features of myofascial pain syndrome, and progress from a less painful state to a more painful one. The clinical presentation apparently encompasses a continuum from barely detectable clinical phenomena of latent trigger points to a complex chronic pain syndrome with currently unsatisfactory treatment options. The mechanisms of trigger point development, transition, and maintenance are not well understood. This review discusses the existing mechanistic evidence and proposes a new conceptualization based on disruption of growth/repair/energy utilisation in the neuromuscular system as one of the possible mechanistic backgrounds of the MPS phenomenon. Accordingly, research opportunities that should be explored in the future are discussed.