Myofascial pain syndrome is a condition characterized by hyperirritable loci called trigger points within tight bands of muscle tissue. Trigger points can cause regional pain and referred pain patterns. The prevalence of myofascial pain syndrome is difficult to determine due to a lack of diagnostic criteria but is estimated to affect 20-95% of patients with musculoskeletal pain. Trigger points are caused by muscle overuse, injury, or other stressors and cause pain through sensitization of nociceptors and release of inflammatory substances. Treatment involves stretching, heat application, trigger point injections, massage, acupuncture, and medications like NSAIDs, muscle relaxants, or antidepressants.

1. Myofascial Pain Syndrome
Amanpreet Saini, MD

2. Myofascial Pain Syndrome
• Myofascial pain is a condition that affects the fascia (connective
tissue that covers the muscles)
• Characterized by the presence of trigger points
• Myofascial trigger point = hyperirritable locus within a taut band of
skeletal muscle, located in the muscular tissue and/or its associated
fascia
• Pain is regional, acute or chronic

3. Prevalence
• No widely accepted diagnostic criteria
• Difficult to establish prevalence of MPS
• Few epidemiologic studies have been published, and the reported
prevalence of MPS ranges from 20% to 95% of patients presenting
with musculoskeletal pain at general medical clinics and pain
management centers

4. Pathophysiology
• Multiple factors may create an autonomic dysregulation  central spinal
cord sensitization  amplify the experience of MPS
• biomechanical and postural factors
• neurologic factors (e.g., radiculopathy)
• psychological elements (depression and anxiety)
• hormonal and nutritional imbalances
• Vasoactive mediators, neurotransmitters and inflammatory mediators
including bradykinin, norepinephrine, serotonin, calcitonin gene–related
peptide, substance P, tumor necrosis factor alpha, and interleukin 1-B have
been identified in the hyperirritable loci of TrPs.
• These substances sensitize nociceptors and are responsible for the sensory
experience of MP, including referred pain and the local twitch response (LTR).

5. Motor phenomena of Myofascial pain
• Excessive acetylcholine (ACh) leakage  creates dysfunctional
endplates  taut muscle band formation
• Excessive ACh release causes sustained muscle contraction
• In a study investigating the hypothalamus-pituitary-adrenocortical
and sympathetic-adrenal-medullary system responses to
experimentally induced stress in patients with MP, plasma
concentrations of cortisol, epinephrine, and norepinephrine were
found to be significantly higher in MP patients than in healthy
controls

6. Trigger Points (TPs)
• An active trigger point (TP) is an
area of extreme tenderness that
usually lies within the skeletal
muscle and which is associated with
a local or regional pain
• A latent trigger point (TP) is a
dormant (inactive) area that has the
potential to act like a trigger point

7. Myofascial Pain Syndrome
• Active myofascial TPs vary in irritability from hour to hour and from
day to day
• TPs irritability may be increased from a latent >> active level by
many factors (stress, muscle in a shortened position, chilling of the
muscle, etc)
• TPs cause stiffness and weakness of the involved muscle

8. Myofascial Pain Syndrome
TPs area activated directly by:
• acute overload
• overwork fatigue
• direct trauma
• extreme cold
• postural strains
• disuse syndrome
TPs are activated indirectly by:
• other TPs
• visceral disease
• arthritic joints
• emotional distress

9. Myofascial Pain Syndrome

10. Trigger Points (TPs)
• Painful on compression
• Can evoke characteristic referred
pain and autonomic phenomena
• When the muscle is slightly
snapped there’s a twitch
response > > “jump sign”

11. Trigger Points (TPI)
Cross-sectional drawing shows flat palpation of a
taut band and its trigger point.
Left: A. The skin is pushed to one side to begin
palpation. B. The fingertip slides across muscle fibers
to feel the cord-line texture of the taut band rolling
beneath it. C. The skin is pushed to the other side at
completion of the movement. This same movement
performed vigorously is called snapping palpation.
Right: A. Muscle fibers are surrounded by the thumb
and fingers in a pincer grip. B. The hardness of the
taut band is felt clearly as it is rolled between the
digits. C. The palpable edge of the taut band is
sharply defined as it escapes from between the
fingertips, often with a local twitch response.

12. Myofascial Pain vs Fibromyalgia

13. Laboratory Findings
• Routine laboratory test: no abnormalities
• EMG & muscle biopsy: no diagnostic abnormalities
• Thermograms of skin overlying active TPs shows increase in skin
temperature, 5-10 cm in diameter
• Reduced skin resistance may be observed in a small region over TP

14. Perpetuating Factors
• Nutritional deficiencies: especially vitamins C, D, B-complex and iron
• Hormone imbalances: low thyroid hormone levels, premenstrual or
menopausal
• Infections: bacterial, viral or yeast
• Allergies: wheat and dairy in particular
• Poor oxygenation of tissues: aggravated by tension, stress, inactivity,
poor sleep, smoking, lung diseases COPD

15. Treatment
• Stretch and Spray Technique
• Heat application / mobilization
• Injection and stretch
• Ultrasound (deep heat)
• Acupuncture
• Transcutaneous Electrical Stimulation
• Massage
• Low-level laser therapy (LLLT, also known as cold laser therapy)
• Medications
• Exercise / muscle rehabilitation

16. Treatment – Stretch and Spray
• Stretch is the action
• Spray is distraction
• Vapocoolant spray:
• Ethylchloride (too cold, flammable, toxic)
• Fluori-Methane (non- flammable, non toxic,
does not irritate skin)

17. Treatment - Exercise
• As the TPs are inactivated and rest pain fades, a carefully graded
exercise program is needed to increase endurance
• Stretching and postural exercises
• Guided stretching has been well documented as successful in reducing
myofascial pain
• Strengthening - i.e. Therabands
• Conditioning - low impact aerobic - warm pool, swimming

18. Treatment – Heat Application
• Moist heat is more effective than dry heat
• Post-treatment muscle soreness is
markedly reduced by applying a hot pack
for a few minutes after stretch and spray
• Electric heating pad - Thermal Pack Moist
Heat

19. Treatment – Ultrasound
• Ultrasound (deep heat)
• Can help inactivate TPs
• This modality can be used in
combination with electrical
stimulation

20. Treatment – TENs
• Transcutaneous Electrical
Stimulation
• High frequency, high intensity, avoid
electrical stimulation of sufficient
intensity to cause muscular
contraction
• Frequently stimulation is applied to
the acupuncture points or to
reference zones where pain is felt,
rather than to TPs where pain
originates

21. Treatment – Massage/Acupuncture
Massage
• Myofascial release
• Deep sedative
• Foam rolls
Acupuncture: The procedure of
inserting and manipulating needles into
various points on the body to relieve
pain or for therapeutic purposes

22. Treatment - Medication
• Corticosteroids - (local injections) can be destructive to muscle fibers
• Analgesics and Muscle Relaxants – some benefit?; acetaminophen,
cyclobenzaprine
• The alpha-2 adrenergic agonist tizanidine has been cited as helpful
• NSAID’s – indicated for excessive muscle soreness after treatment and
in the presence of connective tissue inflammation
• Ibuprofen has been shown to be effective in acute myofascial strain

23. Treatment - Medication
• Antidepressant - short term for reactive depression or long term for
chronic pain management
• Tricyclic antidepressants
• Amitriptyline (Elavil), Nortriptyline (Pamelor)
• Selective serotonin reuptake inhibitors (SSRIs)
• Zoloft, Paxil, Lexapro, Prozac
• Selective serotonin and norepinephrine reuptake inhibitor (SNRIs)
• Savella, Cymbalta

24. Treatment – TPI
• Dry needling
• With the patient recumbent, using
sterile technique to inject TPs with
saline, or local anesthetic and/or
steroids until area becomes non
tender
• There is good evidence to suggest
that there is no advantage of one
injection therapy over another or of
any drug injectate over dry needling.
• Passively stretch

25. Trigger Point Injection - Botox
• BoNT-A produces sustained and prolonged relaxation of muscles by
inhibiting release of Ach at the motor endplate and is itself an
analgesic inhibiting central sensitization
• Injection of botulinum toxin is an emerging therapy that may be
considered in refractory cases of MP, although evidence of its efficacy
is limited at present

26. References
Essentials of Pain medicine. Benzon, Raja, Liu, Fishman, Cohen.
Wall and Melzack's Textbook of Pain. Patrick David Wall, Stephen B.
McMahon, Martin Koltzenburg. ISBN 978-0-7020-4059-7
Khalid S, Tubbs RS. Neuroanatomy and Neuropsychology of Pain.
Cureus. 2017 Oct 6;9(10):e1754. doi: 10.7759/cureus.1754. PMID:
29226044; PMCID: PMC5718877.