Managing Muscle Pain in Medical Practice
Associate Professor Dr Norman A. Broadhurst
Senior Lecturer Musculoskeletal Medicine Flinders University of South Australia
Acute muscle damage which has been brought about by trauma of some kind, such as one would experience in varying sporting activities, is reasonably well understood and treated. The standard treatment being rest, ice, compression, elevation and then mobilising the particular tight tissues until normality is maintained. Most healthy patients whether athletic or not manage to overcome these injuries and are restored to normal function with the minimal amount of disruption to training programs or work output. Unfortunately, some patients are either poorly treated or poorly advised in respect to rehabilitation of the injured part, thus re-injury occurs or the old injury never seems to get better and goes on to a chronic status which may develop myofascial problems as a consequent of the original injury.
There is an idiopathic source of myofascial pain which is difficult to understand in terms of its etiology. Every general practitioner and certainly every practitioner within the broad musculoskeletal field has encountered multiple patients with aching muscles some of which have been secondary to known trauma such as rear-end motor vehicle accidents, but much discomfort comes about slowly with no precipitating cause while other muscle aches and pains can readily be attributed to physiological overuse. There is a marked difference between the overuse of a muscle in terms of heavy work versus very repetitive low tension minimal energy work. None the less, all patients with slow and annoying onset of muscle pain will present to their treating practitioner, complaining that pain prevents them from performing normal daily tasks or interfering with their social or family activities. It therefore becomes the role of the treating physician to be able to identify the area of the discomfort and to relate that to etiology for which a management plan can be implemented.
The various symptoms of tight irritable muscles over the ages has variably been described as myalgia, myalgic spots, myogelosis, fibrositis and psychogenic rheumatism.
Many decades ago, Travell described the genesis of myofascial pain in Postgraduate Medicine (1952). This description helped many practitioners look at the problem of chronic muscle pain in a new light. Subsequently this resulted in the publication of a two-volume work on Trigger Point Therapy by Travell and Simons.
In the absence of no definitive physiology having been attributed to the concept of the trigger point, its identification must be that of a clinical nature.
The essentials of a trigger point, whether it is considered as fact, fascination or fantasy, is that people do have painful areas in muscles. The eradication of these painful areas removes the patient’s pain and restores function.
The philosophy put forward by Travell and Simons indicated that the areas of pain within a muscle were said to be due to chronic overload. This chronic overload produces both objective and subjective signs and symptoms.
Objective - Signs
- Palpable taut band
- Decreased range of movement
- Weakness without atrophy
- No neurological deficit
Subjective - Symptoms
- Localised tenderness
- Fatigue ability
- Spontaneous pain in predictable areas
- Sustained pressure produces referred pain
In the above description the concept of the notorious twitch response has not been mentioned. Although the localised twitch response is a very noticeable phenomena of people with painful muscles, such an entity is not always readily elicited, in fact it would appear from the literature that there is no reliability that irritating a trigger point will always produce a twitch response.
In a recent review of myofascial pain, Kemp (Postgraduate Medicine 1994) stated "The challenge of myofascial pain syndrome lies not only in the lack of specific accepted diagnostic criteria, but also in the difficulty of eliciting specific physical responses. How then, does the primary care physician approach clinic evaluation and treatment?" Kemp went on to say that "the diagnosis of myofascial pain syndrome may become less challenging as clinical criteria become better defined."
Confusion exists as to the place of myofascial pain in compensation cases because the entity occurs in a wide variety of settings and the etiology is not clearly defined. However, early diagnosis with aggressive treatment invariably yields good prognosis but not always.
Treatment modalities for myofascial pain have been via the use of:
- Stretching using post isometric or muscle energy techniques
- Spray and stretch
- Injections - local anaesthetic, saline, depot steroid, sterile water, dry needling, botulinum
While trigger points have had many challenges to their identity and entity, some studies have led to the support of the existence of trigger points. The so-called trigger point area with its well known essential zones and spill-over zones have been subjected to EMG studies and it has been found that sustained spontaneous EMG activity can be found within one to two millimetres of the nidus of all trigger points in the trapezius muscle but such a nidus is absent in non trigger point areas. Hubbard and Berkoff concluded that the trigger points were caused by sympathetically activated interfusal contractions. Other supporting evidence was thought to be forthcoming by the use of dolorimetry and thermography. Unfortunately, there was no evidence to correlate the pain producing areas on dolorimetry with the patient’s pain. Likewise the thermography did not correlate with the colour changes and the area of patient’s pain.
A major problem in regard to identifying the presence of trigger points, is the fact that taut bands have been found in patients with fibromyalgia, myofascial pain and controls. The table below gives a summary of the various criteria which can be used to identify some of the more commonly recognised categories of muscle pain.
Table 3. Comparision of myofascial pain syndrome, fibromyalgia and chronic pain syndrome
|Symptoms||Muscle pain present||Muscle pain present||Muscle pain may/may not be present|
|Acute or chronic Pain||Chronic pain||Chronic pain|
|Signs||Muscle tenderness on palpation||Muscle tenderness on palpation||Muscle tenderness on palpation may/may not be present|
|Symptoms||Local or regional pain distribution||Diffuse pain involving several body regions||Pain may be in any distribution often with "shifting" focus over time|
|Acute onset||Insidious onset||Insidious onset, may follow acute injury or illness|
|Non musculoskeletal symptoms occasionally occur||Non-musculoskeletal symptoms(eg, fatigue, sleep disturbance, irritable bowel) usually present||Non musculoskeletal symptoms usually present|
|Signs||Trigger points with typical zones of reference||Tender points without referred pain in 11 of 18 specific sites||Trigger points and /or tender points may be present, but not necessary for diagnosis|
|Local twitch response present at trigger points||Local twitch response absent at tender points||Local twitch response present only if myofascial syndrome also present|
|Disability||Minimal temporary disability with treatment||Disability, often partial, may/may not be present||Usually complete disability with severe deconditioning|
Nice et al found poor intertester reliability with regard to judgements of physiotherapists when trying to establish the presence of trigger points in patients with low back pain. This study indicated Kappa values of .29 and .38 for positive agreement and negative agreement respectively. A major problem of the study by this was the fact that all patients were examined side lying and the study adopted a statistical pattern to take into consideration identification by chance which some would argue was not relevant in this particular type of study.
In another study Njoo and Van der Does suggested that the clinical use for trigger points could be increased when localised tenderness and the presence of either a jump response or the patient’s recognition of his pain used as criteria for the presence of trigger points. This contrasts markedly with Simons criteria which was published in 1990 (see table 1).
If the management of the patient’s pain depends upon defining and treating the trigger point, then obviously criteria for its establishment is important. Following on from the Njoo and Van der Does study, it would seem that localised tenderness and the recognition of the patient’s complaint would be sufficient criteria to treat the painful area whether the concept of a trigger point is important or not.
Treatment modalities which are open to non medical trained people are the use of various muscle stretching techniques. For those who are medically qualified, injections into the most tender area, which may or may not produce a twitch response, have varying response from one study to another. Normal saline and varying kinds of local anaesthetic with or without steroid have all been established as being efficacious to some extent. What does appear to be important in treating the patient is the patient’s perception of their pain and the worth of the treatment. Following on from psychological studies in relation to fibromyalgia, it appears that patient’s who are more aware and informed of their pain are able to be gainfully employed whereas those who have poor self esteem and poor understanding of their pain profile tend to finish up with disability pensions. It could be that the variation in treatment modalities for this simple entity may well reflect the psychological problems associated with chronic pain.In summary, it could be said that patients with chronic muscular pain in which a central area can be identified can be successfully treated by massage, dry needling or injection of selected substances, followed by stretching and we don’t need to chase trigger points.Table 1. Proposed diagnostic criteria for myofascial pain syndrome
A diagnosis of myofascial pain syndrome can be made if 5 major criteria and at least 1 of 3 minor criteria are satisfied.
1. Localised spontaneous pain
2. Spontaneous pain or altered sensations in expected referred pain area for given trigger point
3. Taut, palpable band in accessible muscle
4. Exquisite, localised tenderness in precise point along taut band
5. Some measurable degree of reduced range of movement
1. Reproduction of spontaneously perceived pain and altered sensations by pressure on trigger point
2. Elicitation of a local twitch response of muscular fibers by transverse "snapping" palpation or by
needle insertion into trigger point
3. Pain relief obtained by muscle stretching or injection of trigger point
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