What Is Myofascial Pain Syndrome?
Myofascial Pain Syndrome (MPS) is a musculoskeletal condition characterized by the presence of myofascial trigger points — palpable hypersensitive nodules within taut bands of skeletal muscle fibers. These points generate local pain and, frequently, referred pain in regions distant from the point of origin.
Unlike fibromyalgia, a condition of diffuse central sensitization, MPS is predominantly regional. A high proportion of pain-clinic consultations (with estimates reaching 85% in some series) involve myofascial components, making it one of the most common causes of chronic pain.
The condition can affect any muscle in the body, but is most frequent in cervical, shoulder, lumbar, and gluteal musculature. Workers who perform repetitive movements — such as musicians, dentists, and office workers — are at elevated risk.
Trigger Points
Painful nodules in taut muscle bands that cause local and referred pain
Referred Pain
Pain felt in regions distant from the point of origin, following predictable patterns
Sensitization
Altered pain perception by the central and peripheral nervous system
Pathophysiology
The Energy Crisis Hypothesis
The most widely accepted model to explain trigger point formation is the Simons integrated hypothesis. According to this theory, local trauma or muscle overload triggers excessive release of acetylcholine at the motor endplate, causing sustained sarcomere contraction.
This continuous contraction compresses local capillaries, reducing oxygen and nutrient supply (localized ischemia). The lack of ATP prevents fiber relaxation, creating a vicious cycle of contraction-ischemia-pain.
Inflammatory Mediators
Microdialysis studies have shown that the biochemical milieu surrounding active trigger points contains elevated levels of substance P, CGRP (calcitonin gene-related peptide), bradykinin, serotonin, and norepinephrine. This "cocktail" of mediators sensitizes local nociceptors.
Types of Trigger Points
Trigger points are classified as active (producing spontaneous and referred pain) and latent (painful only on palpation, without spontaneous pain). Latent points may become active through stress, trauma, or overload.
COMPARISON: ACTIVE VS LATENT TRIGGER POINTS
| CHARACTERISTIC | ACTIVE TRIGGER POINT | LATENT TRIGGER POINT |
|---|---|---|
| Spontaneous pain | Yes, constant or intermittent | No |
| Pain on palpation | Yes, intense | Yes, moderate |
| Referred pain | Yes, reproducible pattern | Possible, less consistent |
| Local twitch response | Present | May be present |
| Functional limitation | Frequent | Generally absent |
| Clinical relevance | Main cause of complaint | May perpetuate dysfunction |
Symptoms
The clinical presentation of MPS varies with the location and number of trigger points involved. Pain is the cardinal symptom, but the syndrome is frequently accompanied by other manifestations.
- 01
Persistent regional pain
Deep, continuous or intermittent pain that does not follow a dermatomal pattern
- 02
Referred pain in predictable patterns
For example, trigger points in the upper trapezius cause temporal and retro-orbital pain
- 03
Palpable taut band
Strip of hardened muscle fibers on physical examination
- 04
Local twitch response
Brief, visible muscle contraction when the trigger point is stimulated
- 05
Limited range of motion
Functional muscle shortening without structural alteration
- 06
Muscle weakness without atrophy
Pain-mediated reflex inhibition of contraction, without real loss of muscle mass
- 07
Autonomic phenomena
Lacrimation, piloerection, localized sweating, or vasomotor changes
- 08
Sleep disturbances
Difficulty finding a comfortable position; nocturnal awakenings due to pain
Diagnosis
The diagnosis of MPS is essentially clinical, based on patient history and physical examination. There are no specific laboratory or imaging tests to confirm the condition, although ultrasonography and elastography can assist in identifying trigger points.
🏥Diagnostic Criteria for Myofascial Trigger Points
Fonte: Adapted from Simons, Travell & Simons — Myofascial Pain and Dysfunction
Essential Criteria (mandatory)
All required- 1.Palpable taut band in the muscle
- 2.Hypersensitive point within the taut band
- 3.Reproduction of referred pain recognized by the patient (for active points)
Confirmatory Criteria
At least 1 of 3- 1.Local twitch response on snapping palpation or needle insertion
- 2.Jump sign — exaggerated patient reaction to palpation
- 3.Reproduction of referred pain on trigger point compression
Differential Diagnosis
- 1.Fibromyalgia (diffuse pain, tender points — not trigger points)
- 2.Radiculopathy (dermatomal pattern, objective neurologic findings)
- 3.Facet arthropathy (axial pain, worsened by extension)
- 4.Tendinopathy (pain in tendons, not in muscle mass)
Complementary Tests
Although the diagnosis is clinical, some tests may be useful to exclude other conditions. Musculoskeletal ultrasonography can identify taut bands and echogenicity changes. Ultrasound elastography shows increased stiffness in trigger point regions.
Differential Diagnosis
Myofascial Pain Syndrome shares clinical features with several conditions, making differential diagnosis a critical step. Correct distinction prevents inappropriate treatments and ensures the most effective therapeutic approach for each patient.
DIAGNÓSTICO DIFERENCIAL
Differential Diagnosis
Fibromyalgia
Read more →- Diffuse pain without specific trigger points
- Generalized sleep disturbance
- No correlation with posture/activity
Testes Diagnósticos
- ACR 2010 criteria
- Tender point mapping
Rheumatoid Arthritis
Read more →- Objective joint synovitis
- Prolonged morning stiffness
- Positive RF/Anti-CCP
Testes Diagnósticos
- RF
- Anti-CCP
- ESR
Radiculopathy
- Pain in dermatome
- Sensory/motor deficit
- Imaging correlation
Testes Diagnósticos
- MRI
- EMG
Neuropathic Pain
- Burning, tingling, electric shock
- Hyperalgesia and allodynia
- Responds to antidepressants/anticonvulsants
Testes Diagnósticos
- DN4 questionnaire
- EMG
Pain Amplification Syndrome
- Pain disproportionate to any stimulus
- Intense psychosocial component
- Predominant central sensitization
Acupuncture modulates central sensitization through descending inhibitory systems
Fibromyalgia versus MPS: The Fundamental Distinction
Differentiating fibromyalgia from MPS is one of the most frequent challenges in clinical practice. In MPS, trigger points sit in palpable muscle taut bands and produce referred pain in predictable patterns — they are hyperirritable nodules with precise anatomic location. In fibromyalgia, tender points are diffuse, without associated taut bands, and the condition is defined by the ACR 2010 criteria as generalized pain with central sensitization symptoms (fatigue, cognitive disturbance, non-restorative sleep).
Both conditions can coexist: patients with fibromyalgia frequently develop overlapping myofascial trigger points, and chronic, refractory MPS can evolve into generalized central sensitization. Treatment must address both components when present.
Radiculopathy versus Myofascial Referred Pain
Myofascial referred pain frequently mimics cervical or lumbosacral radiculopathy and drives diagnostic errors and unnecessary surgical treatments. The distinction lies in pain distribution: radicular pain follows specific dermatomes and is accompanied by objective neurologic deficits (reduced reflexes, myotomal muscle weakness, sensory changes), whereas myofascial referred pain follows the patterns documented by Travell and Simons, without neurologic correlates.
Electroneuromyography (EMG) and magnetic resonance imaging are decisive: neuropathic changes on EMG and root compression on MRI confirm radiculopathy. In MPS, these tests are typically normal, with the diagnosis based exclusively on thorough physical examination and reproduction of referred pain patterns.
Neuropathic Pain and Amplification Syndrome
Neuropathic pain is characterized by distinct sensory qualities — burning, tingling, electric shock sensation — and by sensitization phenomena such as allodynia (pain to normally non-painful stimuli) and hyperalgesia. The DN4 questionnaire helps identify the neuropathic component with high specificity. When it coexists with trigger points, a combined approach targeting both the myofascial and neuropathic components is necessary.
In Pain Amplification Syndrome, the central sensitization component predominates: any stimulus — even a light touch on the skin — is perceived as intensely painful. In these cases, acupuncture may help by modulating descending inhibitory systems, especially the endogenous opioid and serotonergic pathways. Multimodal treatment with psychotherapy is indispensable.
Treatments
MPS treatment is multimodal and must address both symptom relief and elimination of perpetuating factors. Most protocols combine manual techniques, exercises, and, when necessary, minimally invasive interventions.
Manual and Physical Therapies
Ischemic pressure release consists of applying sustained pressure on the trigger point for 60-90 seconds, until relaxation of the taut band is felt. The mechanism involves transient ischemia followed by reactive hyperemia, which improves local perfusion and facilitates metabolite clearance.
Spray-and-stretch, the classic Travell technique, combines application of a refrigerant spray with passive stretching of the affected muscle. The cold stimulus temporarily blocks nociceptive afferents, allowing pain-free stretching. Clinical trials demonstrate efficacy comparable to dry needling for cervical myofascial pain.
Dry Needling
Dry needling uses filiform needles inserted directly into the trigger point to elicit the local twitch response. This response is associated with immediate reduction of spontaneous electrical activity and release of contracted fibers. Systematic reviews suggest dry needling may be superior to placebo for short-term pain reduction (up to about 4 weeks), though study heterogeneity limits definitive conclusions.
Trigger Point Injection
Local anesthetic injection (lidocaine 0.5-1%) into the trigger point provides more immediate relief than dry needling, though long-term results are similar. Adding corticosteroids has shown no extra benefit and increases the risk of tissue injury. Botulinum toxin type A is an alternative for refractory cases, with effect lasting 3-4 months.
COMPARISON OF THERAPEUTIC OPTIONS FOR MPS
| TREATMENT | MECHANISM | EVIDENCE | ADVERSE EFFECTS |
|---|---|---|---|
| Manual myofascial release | Ischemic pressure + reactive hyperemia | Moderate (clinical trials) | Transient local pain |
| Spray-and-stretch | Nociceptive blockade + stretching | Moderate | Cutaneous irritation from cold |
| Dry needling | Local twitch response; neuromuscular reset | Strong (meta-analyses) | Post-needling pain, rare hematoma |
| Lidocaine injection | Local anesthesia + mechanical needle effect | Strong | Allergic reaction (rare), infection |
| Botulinum toxin | Acetylcholine release blockade | Moderate (refractory cases) | Temporary muscle weakness |
| TENS | Pain pathway modulation (gate control theory) | Limited | Cutaneous irritation |
| Therapeutic exercises | Stretching + strengthening + postural correction | Strong | None significant |
Pharmacotherapy
Medications play an adjuvant role in treatment. Muscle relaxants such as cyclobenzaprine (5-10 mg at night) can reduce muscle hyperactivity and improve sleep. Nonsteroidal anti-inflammatory drugs (NSAIDs) offer temporary relief but do not treat the underlying cause. Low-dose tricyclic antidepressants (amitriptyline 10-25 mg) may be useful in chronic MPS through their action on central pain modulation.
Acupuncture as a Therapeutic Option
Acupuncture is recognized as a therapeutic option for MPS, with mechanisms that partially overlap with dry needling. Randomized clinical trials show that acupuncture can reduce pain intensity and improve function in patients with myofascial trigger points, especially in the cervical and lumbar regions.
Physiologically, needle insertion stimulates A-delta and C nerve fibers, prompting the release of endogenous opioids (endorphins, enkephalins), serotonin, and norepinephrine at spinal and supraspinal levels. These mechanisms contribute to both local analgesia and central pain modulation.
Acupuncture is not a standalone solution for MPS. Its best results are seen when combined with stretching exercises, correction of ergonomic factors, and patient education on self-management.
Prognosis and Recovery
MPS prognosis is generally favorable when perpetuating factors are identified and corrected. Most patients show significant improvement with adequate treatment within 4-12 weeks. However, recurrence is common if underlying causes are not addressed.
Phase 1
1-2 weeksAcute Pain Relief
Trigger point deactivation with manual techniques, needling, or injection. Pain control with adjuvant medication if necessary.
Phase 2
2-4 weeksMobility Restoration
Progressive stretching of affected muscles. Start joint mobility exercises and foam-roller myofascial release.
Phase 3
4-8 weeksStrengthening and Postural Correction
Muscle strengthening exercises, workplace ergonomics, global postural reeducation (RPG).
Phase 4
OngoingMaintenance and Prevention
Home exercise program, stress management, active breaks at work. Monthly maintenance sessions if needed.
Myths and Facts
Myth vs. Fact
Myofascial pain is "just muscular" and not serious.
MPS can cause disabling chronic pain, sleep disturbances, and significant functional limitation. It involves central sensitization mechanisms comparable to other chronic pain conditions.
Trigger points and fibromyalgia tender points are the same thing.
Myofascial trigger points are palpable nodules in taut bands that cause referred pain. Fibromyalgia tender points are diffuse tenderness points, without taut bands or referred pain.
Dry needling and acupuncture are identical procedures.
Although they use similar needles, dry needling specifically targets trigger points based on musculoskeletal anatomy. Acupuncture uses its own system of points and meridians, though significant overlap with trigger points exists.
Myofascial pain always appears on imaging tests.
Radiographs and magnetic resonance imaging are generally normal in MPS. The condition is diagnosed clinically. Ultrasonography and elastography are the only tests that can identify compatible tissue changes.
Absolute rest is the best treatment.
Prolonged immobilization worsens MPS by promoting muscle shortening and disuse. Treatment involves active mobilization, stretching, and gradual return to activities.
When to Seek Medical Help
Most cases of myofascial pain respond well to conservative treatment. However, some situations require urgent medical evaluation to rule out more serious conditions.
"Chronic pain is not just a symptom — it is a condition that affects every dimension of the patient's life. Effective treatment requires an approach that integrates body, mind, and social context."
Frequently Asked Questions
Frequently Asked Questions
MPS can be well controlled with adequate treatment, and a portion of patients achieve sustained symptom remission. The condition has a favorable prognosis when perpetuating factors — poor posture, muscle overload, stress — are identified and corrected. However, MPS tends to recur if triggering habits are not permanently modified. The focus should be on controlling active trigger points and preventing new episodes through regular exercise and ergonomics.
The fundamental difference is the extent and mechanism of pain. In MPS, pain is regional — concentrated in specific muscles with palpable trigger points that cause referred pain in predictable patterns. In fibromyalgia, pain is diffuse and generalized (above and below the waist, on both sides of the body), without specific trigger points, and accompanied by systemic symptoms such as chronic fatigue, sleep disturbance, and cognitive fog. Fibromyalgia is a central sensitization condition; MPS is primarily a local or regional musculoskeletal dysfunction.
Although both use similar filiform needles, dry needling and acupuncture are distinct practices. Dry needling is based on Western musculoskeletal anatomy, with the specific goal of eliciting the local twitch response at the trigger point. Acupuncture uses its own system of points and meridians derived from traditional Chinese medicine, though significant overlap exists between acupuncture points and trigger points. In Brazil, by determination of Brazil's Federal Council of Medicine (CFM), acupuncture is a medical specialty.
Most patients show significant improvement in 4 to 12 weeks with adequate treatment. Response time varies with chronicity, the number of muscles involved, and the presence of perpetuating factors. Recent and acute cases tend to respond more quickly than chronic cases of many years. Complete treatment — including the rehabilitation and prevention phase — generally extends over 3 to 6 months.
When performed adequately and progressively, physical exercise is a fundamental part of treatment — it does not cause worsening. What can worsen the condition are poorly oriented exercises, with excessive load on already compromised muscles, or premature return to intense activities. The physician may indicate physical therapy as part of the treatment program to guide the most appropriate exercises. Gentle stretching activities, swimming, and postural exercises are frequently recommended in the rehabilitation phase.
The injection can cause moderate discomfort during the procedure, especially at needle insertion and when it reaches the trigger point — producing the characteristic local twitch response. After the procedure, residual pain may last 24 to 48 hours. However, most patients report that the transient discomfort is offset by pain improvement in the following hours and days. Local anesthetic minimizes discomfort during the injection.
Myofascial Pain Syndrome (MPS) is a musculoskeletal condition characterized by trigger points — hyperirritable nodules in taut bands of skeletal muscle — that cause local and referred pain in predictable patterns. The main causes include repetitive muscle overload, direct trauma or cumulative microtrauma, prolonged poor posture, emotional stress, and a sedentary lifestyle punctuated by intense exertion. Perpetuating factors such as nutritional deficiencies, sleep disorders, and adjacent joint dysfunction hinder spontaneous resolution and must be identified and treated by the physician.
Diagnosis is essentially clinical, based on detailed history and thorough physical examination by the physician. The classic criteria include a palpable taut muscle band, a point of painful hypersensitivity within the band, reproduction of the patient's characteristic pain on compression and, frequently, the local twitch response on needling. There is no specific laboratory or imaging test for MPS; high-resolution musculoskeletal ultrasonography can help identify taut bands in equivocal cases, and complementary tests are used to exclude other diagnoses.
Conventional treatment combines pharmacologic and non-pharmacologic approaches. The most commonly used medications include analgesics, anti-inflammatories, muscle relaxants and, in chronic cases, antidepressants at analgesic doses (amitriptyline, duloxetine). Procedural interventions include trigger point injection with local anesthetic or saline and dry needling. Non-pharmacologic treatment includes progressive stretching, postural correction, thermotherapy, and electrotherapy. The physician may prescribe physical therapy as part of the rehabilitation program, coordinating all interventions individually.
MPS itself is rarely an emergency, but some warning signs require immediate medical evaluation to rule out serious conditions that may mimic myofascial pain. Seek urgent care if pain is accompanied by high fever, unexplained weight loss, severe pain that progressively worsens without rest relief, radiation to limbs with tingling or muscle weakness, or if it occurs after recent trauma. Chest pain resembling cervical or interscapular MPS should also be evaluated urgently to exclude cardiac or pulmonary causes.