Is Fibromyalgia a Central Pain State?
Robert M. Bennett in The Clinical Neurobiology of Fibromyalgia and Myofascial Pain, 2020
symptom-chronic multifocal pain-and one sign-generalized allodynia/ hyperalgesia (1). The patient who is diagnosed with FMS, however, is polysymptomatic. Besides pain there is fatigue, sleep disturbance, psychological distress, impaired muscle function, and symptoms that are usually regarded as stress-related. Fibromyalgia is an illness, a syndrome, that effects three systems that regulate our well being: the nociceptive system, the stress-regulating system, and the immune system. These systems interact with each other, making it difficult to determine which of them is primarily affected in an individual patient. Psychological factors, personality traits, and social circumstances play a role for the total clinical picture. Fibromyalgia is indeed a biopsychosocial syndrome. The biological part concerns mainly pain and allodynia/hyper-algesia as well as biological changes related to continuous physical and emotional stress. This article will deal only with pain and allodynia. Allodynia is pain elicited by normally nonpainful stimuli. Hyperalgesia is increased pain intensity and prolonged pain duration evoked by stimuli that normally are painful.
Altered Somatosensory Pathways
Golara Honari, Rosa M. Andersen, Howard Maibach in Sensitive Skin Syndrome, 2017
Hyperesthesia is a condition that involves an abnormal increase in cutaneous sensitivity including pain, touch, and thermal sensation. Hyperesthesia is observed in many neurologic disorders such as herpes zoster, peripheral neuropathy, and radiculopathies. One of the possible mechanisms underlying hyperesthesia is that pain thresholds are lowered in areas with tissue inflammation or injury. Another explanation is that inflammation activates silent nociceptors and/or elicits perpetuating nerve signals, leading to long-lasting changes and nociceptor sensitization. These phenomena contribute to the amplification and persistence of pain. On the other hand, allodynia is pain caused by excitation of low-threshold sensory nerve fibers in response to nonnociceptive stimuli, whereas hyperalgesia is exaggerated pain to noxious stimuli (22–24).
Low Back Pain and Sciatica: Pathogenesis, Diagnosis and Nonoperative Treatment
Gary W. Jay in Practical Guide to Chronic Pain Syndromes, 2016
Neuropathic pain often occurs with limb involvement and is often characterized as thermal, jabbing, shooting, or like pins and needles, whereas nociceptive pain is usually described as dull and aching and is aggravated by biomechanical loading. Although, neuropathic pain may increase with exposure to increased biomechanical forces, it is usually worse at night or at rest and associated with other neurological symptoms such as reduced sensation or weakness. Determining the character of pain as neuropathic is helpful clinically but does not differentiate among the various neuropathic conditions that may be causative (30). The presence and location of neuropathic pain within the peripheral or central nervous system can be determined by neurological abnormalities found on physical examination. Neuropathic pain may also be seen in the thoracolumbar regions as a sign of cervical or thoracic myelopathy. Furthermore, the presence of allodynia and hyperalgesia are considered cardinal signs of neuropathic pain (30, 31). Allodynia is pain that results from a stimulus that does not normally evoke pain, whereas hyperalgesia is an exaggerated response to a stimulus that is normally not painful (1, 30, 31).
Algometry for the assessment of central sensitisation to pain in fibromyalgia patients: a systematic review
Published in Annals of Medicine, 2022
Pablo de la Coba, Casandra I. Montoro, Gustavo A. Reyes del Paso, Carmen M. Galvez-Sánchez
Fibromyalgia (FM) is a syndrome characterised by widespread, persistent and diffuse pain that is usually accompanied by a wide range of physical (e.g. fatigue, insomnia and stiffness) and psychological (e.g. anxiety, depression and cognitive alterations) symptoms [1–3], which are of relevance for its diagnosis [3]. FM seems to be more prevalent in females than males (9:1) [4]. Another hallmark of FM is pain-related hyperresponsivity [5], which underlies two of its characteristic symptoms: (1) allodynia, defined as increased sensitivity to innocuous stimulation; and (2) hyperalgesia or excessive response to painful stimulation, which may be primary or secondary [6]. Primary hyperalgesia refers to sensitisation of nociceptors (peripheral sensitisation), whereas secondary hyperalgesia involves increased responsiveness of the central nervous system (CNS) to painful stimulation (central sensitisation, CS) [7]. While the aetiology of FM remains unknown, its pathophysiology has been widely related to CS processes [8,9]. CS can be defined as an increase in CNS pain responsiveness as a result of altered nociception at the brain and spinal cord levels [7]. Three main CS processes have been distinguished: (1) long-term potentiation of synaptic transmission in the CNS, (2) activation of certain pain facilitatory pathways outside the receptive fields, and (3) dysfunction in descending inhibitory pain mechanisms [10].
Opioid MOP receptor agonists in late-stage development for the treatment of postoperative pain
Published in Expert Opinion on Pharmacotherapy, 2022
Qiu Qiu, Joshua CJ Chew, Michael G Irwin
Cebranopadol is first-in-class agent with both MOP and NOP receptor agonism. NOP receptor agonism gives cebranopadol broad pharmacodynamic advantages and these appear applicable to postoperative analgesia. It has many pharmacological properties that are useful in the management of chronic pain. These include its oral formulation, efficacy in neuropathic pain, once-a-day administration, and reduced hyperalgesia and allodynia. These properties could also be beneficial in acute postoperative pain, with oral dosing compatible with premedication prior to surgery. Moreover, a reduction in respiratory depression and abuse potential may serve to increase the safety of this agent both in hospital, and the community – if patients are planned for discharge whilst still requiring opioid analgesia. Given its efficacy in neuropathic pain, the investigation of a potential role in surgically induced neuropathic pain is important. This should include evaluating its use in surgeries such as amputations, mastectomy, and thoracotomy. Lastly, cebranopadol’s reduction in hyperalgesia and allodynia would lend biological plausibility for an influence on chronic postsurgical pain. Longitudinal evaluation should assess the incidence of this entity in high-risk groups.
Temporomandibular disorder in individuals with spinal cord injuries
Published in The Journal of Spinal Cord Medicine, 2022
Mayara Rangel, Marcos Venturini Ferreira, Maria Teresa Botti Rodrigues dos Santos, Carla Bertini Godoy da Silva, Marcelo Munhóes Romano, Renata Oliveira Guaré
A larger number of evaluated subjects could possibly help to identify different correlations, and it is important to perform retrospective and cohort studies associating dental and medical history in patients with SCI and TMD. Since patients with SCI have important psychosocial changes during post-injury life. We propose that other relevant factors can be analyzed in future studies, such as the influence of psychological states, stress in the installation of parafunction worsening of TMD, to analyze previous dental history regarding TMD before SCI, as well as to extract more information about the SCI e.g. clinical status of the patient, cause of the injury, proposed treatment, whether surgical intervention was necessary, and the rehabilitation method used. Further research can assess hyperalgesia, allodynia, and pain perception in these patients.
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