Transcript Document

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).
DIAGNOSIS
It 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 Examination
Firstly, 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 Factors
Once 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 hemipelvis
Systemic 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 reference
The 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 pain
Latent MTRP is painful only when directly palpated/compressed
Referred pain is typically not seen
Primary 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 muscle
Key MTRP is responsible for activating one or more satellite TRPs
in its zone of reference; inactivation will also inactivate associated
satellite TRPs
Satellite 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 with
increased 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
TREATMENT
Only 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
Medications
Simple 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 Stretch
Electrical Stimulation
Phonophoresis and Iontophoresis
Stretching
Soft-Tissue Treatment
Relaxation
Strengthening