The Myofascial Pain Syndrome Dr:Moallemy. INTRODUCTION The MPS has been defined by the International Association for the Study of Pain as a regional painful.

The Myofascial Pain Syndrome

Dr:Moallemy

INTRODUCTION

The MPS has been defined by the International Association for the Study of Pain as a regional painful condition associated with the presence of trigger points (TRPs)Myofascial trigger points (MTRPs) are loci of hyperirritability,which,

when subjected to mechanical pressure, give rise to characteristic patterns of referred pain.The MPS is a very common occurrence in pain clinic populations and may not be diagnostically straightforward. The diagnosis is basically a clinical one, as it is associated with normal radiological studies as well as having no diagnostic laboratory studies.The older names included myofibrositis, myofascitis, fibromyositis, myogelosis,and fibrositis, to name a few.

The largest single tissue type in the body is skeletal muscle, which accounts for 50% of the body’s weight.Clinically, the patient with an MPS may describe muscular pain, which is more frequently diffuse, but which can be localized. The attributes for this pain may be deep, dull, aching, and continuous. It is rare to have more neuropathic attributes such as burning, or vascular attributes such as throbbing.The onset may be posttraumatic, following an acceleration/deceleration injury (“whiplash”) or a slip and fall.

It may begin insidiously, with the patient having worked at a desk on a computer for many hours or days.

Aside from pain, other common complaints associated with an MPS may include muscle stiffness, fatigue, tenderness, weakness, sleep disorder, autonomic nervous system symptoms and even poor balance, dizziness, and ear pain (if more rostral musculature is affected).

DIAGNOSISIt has been noted that the MPS is seen more frequently in women than men, and it is most often seen in adults between the ages of 31 and 50,although TRPs have also been diagnosed in children and young adults.Women, more frequently than men, appear to develop symptomatic myofascial pain.To attain a correct diagnosis ,a musculoskeletal examination should follow a general and neurological examination.It is the author’s preference to have a mirror in the examination room where the patient can use it to see what, if any, asymmetries are found.

The patient must be in a gown. You can then easily observe any physical asymmetries, such as finding one shoulder or one hip elevated.

the musculoskeletal examination must be as thorough as possible, with more care, if necessary, being given to the area of the origin

of pain or etiology.

Pain related to chronic MPSs can induce disability from not only the attributes of the pain, but also from depression, sleep disturbances, other psychological and behavioral problems, and physical deconditioning secondary to lack of exercise.

TRP ExaminationFirstly, the patient must be warm and comfortable. If the patient is in a cold examination room, the general musculature will become tense, and a TRP examination may be futile. Secondly, the fingernails on the examiner’s hands must be short, so as to avoid scrapping the patient’s skin.

Flat palpation is the best way to begin, particularly, in large and smaller muscles that can be palpated from only one side. The fingers are slightly bent,with the fingertips perpendicular to the palm. The patient may be sitting or lying prone. The skin above the region of the suspected TRP is pushed to one side,and the fingertips slowly traverse the area. If the patient is warm and the muscle is relaxed, a taut band may be easily palpated, and the trigger point, likewise,is easily palpated.

If the movement of the fingers is done too quickly (snapping palpation), it is likely to obtain a local twitch response (LTR), which is painful.Pincer palpation can be used in muscles such as the sternocleidomastoid,which can be grasped between the thumb on one side of the muscle and the fingers on the other.Another important diagnostic exercise is to press directly over an active TRP, which may lead to the development/demonstration of referred pain.Pain related to MTRPs may be aggravated by pressure directly on the TRP;MTRP pain may be decreased by short period of rest, moist heat applied directly to the TRP, slowly and passively stretching the involved muscles, short periods of light activity with movement,

Depending on the location of active TRPs, patients may develop a number of nonpainful symptoms of MTRPs. These may include pilomotor activity(“goose flesh”), changes in sudomotor activity (sweating), excessive lacrimation,and other autonomic signs and symptoms such as vasoconstriction causing one limb or region to appear “colder” to palpation, as well as dizziness.

Dermatographia is the term for using the fingernail or a pencil to write or draw on the skin and, then, observe the areas become red and raised. This is seen most commonly on the skin over musculature affected by active TRPs, particularly over the muscles of the back, shoulders, neck, and torso.

Depression and sleep disorders are also commonly seen.

Differential Diagnosis of MTRPs and Other Disorders

• Acaveat is that many times patients with a herniated disk(s) will also have a MPS with TRPs referring pain.

The clinician should look for TRPs after performing an appropriate examination and performing spinal MRIs and/or electromyogram (EMG)/nerve conduction studies (NCVs).

While TRPs are common, clinicians must first rule out other clinical causes of a problem.

Clinicians should first deal with the problem that may cause the most severe pathological difficulties.

Endocrine Disorders Associated with Myofascial Pain

It is not uncommon to find dozens of patients who present with muscle pain,spasm, and TRPs that are secondary to a primary endocrine disorder. The two most common are hypothyroidism and menopause. It is a good practice to perform a confirmatory laboratory test, and if clinical suspicions are correct, send the patient to an endocrinologist.The most common complaints found in hyperthyroidism include muscle weakness and pain, TRPs“Male menopause,” secondary to significant decreases in serum testosterone,may be associated with myofascial pain and TRPs, along with weakness and depression. Exogenous testosterone may relieve these symptoms.Muscle weakness, wasting, spasm, and pain are frequently associated with Cushing’s disease

Primary adrenal insufficiency, or Addison’s disease, may present with muscle pain, spasm or, on occasion, knee contractures.

Pituitary–adrenal insufficiency typically is found to be caused by adrenal atrophy secondary to tumor, hemorrhage or even infarction of the pituitary. The presenting symptoms not infrequently include myofascial pain and TRPs

Hypoparathyroidism, secondary to surgical damage or removal may be associated with acute muscle spasms and even tetany secondary to decreased serum calcium.

Hyperparathyroidism is associated with an increased level of serum calcium,Muscle weakness, or myopathy, may be secondary to elevated calcium.

Perpetuating FactorsOnce a myofascial pain syndrome with TRPs has manifested,there are a number of things that may perpetuate the syndrome. It is important to identify these mechanical and/or systemic problems and deal with them appropriately.Mechanical factors may include tight collars, tight brassiere straps, carrying heavy purses or bags over the shoulders, compressing the hamstring muscle by the hard edges of chairs, and ergonomic problems associated with work, such as having a computer monitor that is too high, or a keyboard that is not properly placed or too difficult for a patient to utilize comfortably.Postural abnormalities must be identified and corrected.Other common problems include inherent structural inadequacies, such as the short leg syndrome and a small hemipelvisSystemic perpetuating factors include endocrine or metabolic factors, folic acid deficiency, and low iron levels.

Psychological stressors are of equal importance in terms of perpetuating a myofascial problem.The “entire patient” must be treated, physically,mentally, and emotionally. Pain is, after all, a biopsychosocial problem

Myofascial Trigger Points (MTRPs)

MTRPs are small, hyperirritable foci in muscles and fascia which are most typically found in a taut band of skeletal (striated) muscle. They can also be found in ligaments, tendons, skin, joint capsule, and periosteum. They may be localized to a single muscle or found in multiple muscle groups. When pressure is directed onto the active TRP, a local or referred pain pattern is obtained.The referred pain pattern will be consistent for a specific TRP. The “zone of reference” is the region of referred pain in an area distant from the TRP. Patients may also perceive paresthesias or numbness in the zone of referenceThe areas of referred pain are not consistent with myotomal, dermatomal,or sclerotomal patterns

Nerve compression that can induce obvious neuropathic electromyographic changes is associated with an increased number of active MTRPs.

In summary, TRPs may be directly activated by work overload, muscle overwork fatigue, direct trauma, and radiculopathy (38). Indirect TRP activation can occur via other existing TRPs, visceral disease, joint dysfunctions, arthritic joints, and by stress/emotional distress.

There are six different classifications of TRPs:

Active MTRP is tender and, with direct compression, produces referred painLatent MTRP is painful only when directly palpated/compressed

Referred pain is typically not seenPrimary MTRP is centrally located in the muscle; typically activated by an acute or chronic muscle work overload, or by repetitive overuse of the muscle in which it occurs; it is not secondary toTRP activity in another muscleKey MTRP is responsible for activating one or more satellite TRPs in its zone of reference; inactivation will also inactivate associated satellite TRPsSatellite MTRP is centrally located in the muscle; induced via mechanical or neurogenic stimulation by the activity of a key TRP;Attachment TRP is found at the musculotendinous junction and/or where the muscle attaches to the bone; this induces an enthesopathy

Active TRPs may spontaneously convert to latent TRPs, and vice versa.

latent TRPs which do not produce spontaneous pain may also cause weakness.

Trigger Point (TRP) Hypothesis(PATHOPHYSIOLOGY)

it is thought that muscle activity secondary to significant muscle stress which leads to muscle injury and capillary constriction is the initiating event. The muscle injury will induce a release of algetic substances, which stimulate muscle nociceptors.Sympathetic nervous system activation occurs in the evolving pathological state. Ischemia occurs from capillary contraction from the muscle contraction and causes hypoperfusion. The regional pH becomes acidic, which will inhibit acetylcholine-esterase (AChE). CGRP, which is released from nociceptors in the injured muscle, will also inhibit AChE, increases ACh release and up-regulates cholinergic receptors. This cascade leads to increased cholinergic activity withincreased sarcomere hypercontraction, the formation of taut bands and increased frequency of miniature endplate potentials.

From the two entities, sympathetically maintained pain and the MPS, it is clinically possible, if not probable, that the multitudes of patients with soft-tissue injuries leading to MPSs who do not recover within a short period of time (1–3 months) of appropriate PT may have developed secondary sympathetically maintained pain.

Research data indicate that some receptors in skin and skeletal muscle can be influenced by sympathetic activity. It appears that the sympathetic influence on muscle receptors is functional in pathological states, but not under normal physiological conditions

TREATMENTOnly after the clinical diagnosis of MPS has been made, and the physician has ruled out any endocrinopathies or other primary problems, can the patient begin therapy.Patients who are injured (in a motor vehicle accident, slip and fall, or other injury) should be evaluated earlier rather than later.The most conservative treatment approach is the initial use of medication.Acute muscle relaxants will not affect a preexisting MPS, nor will a nonsteroidal anti-inflammatory drug (NSAID). However, in the presence of an acute softtissue injury, these medications may be helpful.NSAIDs such as ketoprofen or ibuprofen should be used to help a patient maintain their ability to function, as bed rest is not a beneficial treatment.

In cases of severe soft-tissue trauma, physical therapy (PT) may be necessary within a week of injury, when the initial tenderness has possibly remitted to some degree. The purpose of PT is to decrease edema, spasm and pain, and improve muscle pain/spasm and joint ROM.Patients with MTRPs may need trigger point injections (TPIs).The majority of patients can be placed on appropriate medications, taught the appropriate muscle stretching exercises and, within several weeks, regain their preinjury status.The most important reason to make the correct diagnosis and perform appropriate treatment as early as possible is to prevent the development of chronicity.When patients with a chronic MPS are seen, prior to initiating treatment,they should be evaluated for depression,anxiety disorder iatrogenic medication overutilization, and their psychosocial milieu must be detailed to enable the development of a full, appropriate individualized, interdisciplinary pain management program

MedicationsSimple analgesics include aspirin and acetaminophen. The recommended dosage is two tablets every six hours as needed.NSAIDs can be used,and include : Ibuprofen, Anaprox, Ketoprofen

Ketorolac, Celecoxib.Muscle relaxants, may be used, and include, for acute muscle spasm.Antidepressant medications (ADMs) are also very useful, particularly the tricyclic antidepressants for pain. The TCA medication of choice is amitriptyline, The typical dosage is between 10 and 50 mg at night.Doxepin is also a very good tricyclic. Anticholinergic side effects such as sedation are reduced (but not by much) when compared to amitriptyline. It does not work on the sleep architecture. It is used at the same dosage levels of amitriptyline.

The SSRIs include Prozac, Paxil, and Zoloft, among others.

They should be given in the morning.

Norepinephrine/serotonin reuptake inhibitors (NSRIs) such as venlafaxine,and duloxetine may also be used.

A systematic review (NIN Consensus Development Panel on Acupuncture) found acupuncture, or deep, dry needling, useful in the treatment of myofascial pain (and fibromyalgia)

One RCT indicated that US gave no pain relief, but massage and exercise decreased the number and pain intensity of MTRPs.

Physical Therapy

Vapocoolants/Spray and StretchElectrical StimulationPhonophoresis and IontophoresisStretchingSoft-Tissue TreatmentRelaxationStrengthening