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Myofascial pain syndromes and their evaluation

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Myofascial pain refers to a specific form of soft-tissue rheumatism that results from irritable foci (trigger points) within skeletal muscles and their ligamentous junctions. It must be distinguished from bursitis, tendonitis, hypermobility syndromes, fibromyalgia and fasciitis. On the other hand it often exists as part of a clinical complex that includes these other soft-tissue conditions, i.e., it is not a diagnosis of exclusion. The clinical science of trigger points can be traced to the pioneering work of Kellgren in the 1930s, with his mapping of myotomal referral patterns of pain resulting from the injection of hypertonic saline into muscle and ligaments. Most muscles have characteristic myotomal patterns of referred pain; this feature forms the basis of the clinical recognition of myofascial trigger points in the form of a tender locus within a taut band of muscle which restricts the full range of motion and refers pain centrifugally when stimulated. Although myofascial pain syndromes have been described in the medical literature for about the last 100 years, it is only recently that scientific studies have revealed objective abnormalities.

Section snippets

Definitions

  • Myofascial pain: pain arising from muscles or related fascia.

  • Active trigger point: an active trigger point causes spontaneous pain at rest, with an increase in pain on contraction or stretching of the muscle involved. There is often a restriction of its range of motion. Pain on motion may cause ‘pseudo-muscle weakness’ due to reflex inhibition (Table 1).

  • Latent trigger point: a latent trigger point is a focal area of tenderness and tightness in a muscle that does not result in spontaneous pain.

Prevalence

It has been estimated that some 44 million Americans have myofascial pain problems.5 A study from an internal medicine group practice found that 30% of patients with pain complaints had active myofascial trigger points.6 A report from a clinic specializing in head and neck pain reported a myofascial etiology in 55% of cases.7 Patients evaluated in one pain management center were found to have a myofascial component to their pain in 95% of cases.8 There is increasing awareness that active

The key elements in the case history suggesting a diagnosis of myofascial pain

The possibility that there may be myofascial syndrome should be considered in any patient in whom a well-defined etiology for their pain cannot be found. The clinical diagnosis of myofascial pain is dependent on the physician being aware of this diagnosis as a possible cause for the patient's pain complaint.3 In a patient with a recent muscle injury or symptoms of repetitive strain the possibility of a myofascial component is self-evident. In a patient with a focal pain complaint that cannot be

The key elements in the physical examination of suspected myofascial pain

Rheumatologists are well trained in the diagnosis of arthritis, tendonitis and bursitis, but usually lack training in the diagnosis of myofascial pain syndromes. Myofascial pain syndromes may mimic a large number of other disorders20; furthermore, the finding of myofascial trigger points does not rule out other conditions. Thus, a general history and physical examination is, as always, a prerequisite for a competent and informed diagnosis.

Examining for the presence of myofascial trigger points

Reliability of Diagnosis

There are no well-validated diagnostic criteria for the identification of trigger points. The usual recommendations for identifying a trigger point specify that gentle palpation should be performed across the direction of the muscle fibers in order for the examiner to identify a longitudinal region of nodularity (i.e. the taut band). If the taut band can be ‘snapped’, a local contraction of the muscle may be observed (i.e. ‘the twitch response’). The patient's response to these maneuvers is a

Experimental Muscle Pain

The pioneering studies of experimental myofascial pain were performed by a future rheumatologist, Jonas Henrik Kellgren, when he was a student of Sir Thomas Lewis at University College Hospital, London, UK. Lewis was interested in the precise localization of pain by a skin stimulus, whereas pain from deeper structures was not so accurately localized. In the 1930s it was assumed that most cutaneous pain resulted from a ‘neuritis’, and Lewis challenged this explanation by experiments using

Histological, Neurophysiological and Biochemical Findings

The precise pathophysiological basis for the trigger point phenomenon is still not fully understood, but there is emerging evidence for abnormal neurophysiology and a perturbed biochemical milieu being relevant to the histological finding of ‘contracture knots’.

Common Clinical Syndromes of Myofascial Pain

A myofascial pain syndrome may be due to just one trigger point, but more commonly there are several trigger points responsible for any given regional pain problem. It is not uncommon for the problem to be initiated with a single trigger point, with the subsequent development of satellite trigger points that evolve over time due to the mechanical imbalance resulting from the reduced range of movement and pseudo-weakness. The persistence of a trigger point may lead to neuroplastic changes at the

Prognosis

Uncomplicated myofascial pain syndromes usually resolve with appropriate correction of predisposing factors and myofascial treatment.72 If the symptoms are persistent, due to ineffective management, the development of segmental central sensitization may lead to a stubbornly recalcitrant pain disorder. In some such cases, the spread of central sensitization leads to the widespread pain syndrome of fibromyalgia.4, 73

Treatment

The effective management of myofascial pain syndromes requires attention to the following issues*72, 74:

References (81)

  • H. Nie et al.

    Temporal summation of pain evoked by mechanical stimulation in deep and superficial tissue

    Journal of Pain

    (2005)
  • P. Bajaj et al.

    Osteoarthritis and its association with muscle hyperalgesia: an experimental controlled study

    Pain

    (2001)
  • H.Y. Ge et al.

    Sympathetic facilitation of hyperalgesia evoked from myofascial tender and trigger points in patients with unilateral shoulder pain

    Clinical Neurophysiology

    (2006)
  • L. Rosendal et al.

    Increased levels of interstitial potassium but normal levels of muscle IL-6 and LDH in patients with trapezius myalgia

    Pain

    (2005)
  • L. Rosendal et al.

    Increase in muscle nociceptive substances and anaerobic metabolism in patients with trapezius myalgia: microdialysis in rest and during exercise

    Pain

    (2004)
  • R.D. Gerwin

    Myofascial pain syndromes in the upper extremity

    Jorunal of Hand Therapy

    (1997)
  • A.G. Fam

    Approach to musculoskeletal chest wall pain

    Primary Care

    (1988)
  • J. Borg-Stein et al.

    Focused review: myofascial pain

    Archives of Physical Medicine and Rehabilitation

    (2002)
  • D.G. Simons

    Myofascial pain caused by trigger points

  • J.G. Travell et al.

    Myofascial pain and dysfunction: the trigger point manual

    (1983)
  • A.H. Wheeler

    Myofascial pain disorders: theory to therapy

    Drugs

    (2004)
  • S.A. Skootsky et al.

    Prevalence of myofascial pain in general internal medicine practice

    The Western Journal of Medicine

    (1989)
  • R.D. Gerwin

    A study of 96 subjects examined for both fibromyalgia and myofascial pain

    Journal of Musculoskeletal Pain

    (1995)
  • C. Fernandez-de-Las-Penas et al.

    Myofascial trigger points and their relationship to headache clinical parameters in chronic tension-type headache

    Headache

    (2006)
  • J. Borg-Stein et al.

    Soft tissue determinants of low back pain

    Current Pain and Headache Reports

    (2006)
  • D.G. Simons et al.

    Myofascial origins of low back pain. 1. Principles of diagnosis and treatment

    Postgraduate Medicine

    (1983)
  • F. Ardic et al.

    The comprehensive evaluation of temporomandibular disorders seen in rheumatoid arthritis

    Australian Dental Journal

    (2006)
  • J. Jarrell

    Myofascial dysfunction in the pelvis

    Current Pain and Headache Reports

    (2004)
  • R. Doggweiler-Wiygul

    Urologic myofascial pain syndromes

    Current Pain and Headache Reports

    (2004)
  • R.U. Anderson et al.

    Sexual dysfunction in men with chronic prostatitis/chronic pelvic pain syndrome: improvement after trigger point release and paradoxical relaxation training

    Journal of Urology

    (2006)
  • A.E. Sola et al.

    Incidence of hypersensitive areas in posterior shoulder muscles

    American Journal of Physical Medicine

    (1955)
  • H.J. Flax

    Myofascial pain syndromes–the great mimicker

    Boletin de la Asociacion Medica de Puerto Rico

    (1995)
  • J. Travell et al.

    The myofascial genesis of pain

    Postgraduate Medicine

    (1952)
  • J. Travell et al.
    (1992)
  • R.D. Gerwin

    A review of myofascial pain and fibromyalgia – factors that promote their persistence

    Acupuncture in Medicine

    (2005)
  • F. Wolfe et al.

    The fibromyalgia and myofascial pain syndromes: a preliminary study of tender points and trigger points in persons with fibromyalgia, myofascial pain syndrome and no disease

    Journal of Rheumatology

    (1992)
  • E. Tunks et al.

    The reliability of examination for tenderness in patients with myofascial pain, chronic fibromyalgia and controls

    Journal of Rheumatology

    (1995)
  • J.H. Kellgren

    Observations on referred pain arising from muscle

    Clinical Science

    (1938)
  • T. Graven-Nielsen et al.

    Induction and assessment of muscle pain, referred pain, and muscular hyperalgesia

    Current Pain and Headache Reports

    (2003)
  • L.M. Mendell et al.

    Response of single dorsal cord cells to peripheral cutaneous unmyelinated fibers

    Nature

    (1965)
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