Pathophysiology of myofascial trigger points: a review of literature

Abstract

The most common source of musculoskeletal algia is the myofascial pain syndrome (MPS), its occurrence is related to excessive involuntary muscle contraction and is characterized by hardened regions. Myofascial trigger points (MTP) are hypersensitive nodules that refer pain spontaneously or under mechanical stimuli, present in 37 % of men and 65 % women, and may be classified as: active, latent, satellite, central junction. Assuming this pathological situation affects high number individuals may cause functional impairment and compromised quality life realized the need enlarge and update searches about MTP physiology. This literature review was conducted in English, Portuguese, and Spanish articles, published since 2009 (trigger points, musculoskeletal pain, MPS) in electronic databases: Bireme, PEDro and Scielo, and a book 2007. There are four important assumptions about the pathogenesis and pathophysiology of MTP: muscle spindle, the neuropathic process, scar tissue and terminal buttons and dysfunctional energy crisis. Most studies have only two classifications for MTP: active and latent, and few describe in great detail about the possible hypotheses of the pathogenesis of these. Recent literature is sparse regarding the physiology and aetiology, however, recent studies have sought to understand the pathophysiology ensure that the hypothesis with the highest validity.

The role of oxidative stress, inflammation and glial cell in pathophysiology of myofascial pain

“…Prolonged muscle contraction, ischemia/hypoxia, metabolic disorders, and cell stress also lead to increased release of neurotransmitters, inflammatory cytokines, and myokines, which necessary in the pathophysiology of myofascial pain [2,25,31]. Damage to these muscles cause the release of neuropeptides, cytokines, and inflammatory substances such as potassium, bradykinin, cytokines, tumor necrosis factor, interleukin 1β, norepinephrine, protons, prostaglandins, ATP and substances P that can stimulate nociceptors in the muscle thereby releasing CGRP (calcitonin gene-related peptide) [2,8,9,15,18,25]. Mast cells will be degranulated by substance P and release serotonin, histamine, and upregulation of anti-inflammatory cytokines (IL-4 and IL-10) and also the pro-inflammatory factors (TNF-α and IL-6).…”

“…Decreased oxygen will disrupt mitochondrial metabolism. In this situation, the reduction of ATP will cause an energy crisis and distress in the tissue [2,6,8,10,14,25,26]. Therefore anaerobic metabolism will occur that produces lactic acid, reducing the intramuscular pH [14].…”

Pathophysiological substantiation of the complex approach to rehabilitation of patients with myofascial pain syndrome of the neck region

“…Возникшее напряжение снижает кровоток, способствуя локальной гипоксии с последующим нарушением метаболизма в митохондриях. В них снижается количество аденозинтрифосфата, что приводит к энергетическому кризису [3,7,8]. Постоянное сокращение приводит к каскаду биохимических реакций, включающих высвобождение вазоактивных компонентов, воспалительных факторов и сенсибилизирующих веществ, что в свою очередь ведет к активации ноцицепторов и возникновению болевого синдрома [5,6].…”

Comparison of the effects of muscle energy technique and positional release of latent trigger points of the ternocleidomastoid muscle on changes in pain threshold and bioelectrical activity of the trapezius muscle

“…The head, neck, back, and shoulder pain co-occurs with it significantly impacts people's productivity and quality of life [1]. Pain in these areas is usually associated with characteristic stiffness, excessive and involuntary muscle contraction, and the presence of palpable, hypersensitive, small-shaped points referred to as myofascial trigger points (TPs) [2,3]. TPs are defined as severely irritated areas occurring in skeletal muscles or muscles fascia.…”