eMedicine Specialties > Physical Medicine and Rehabilitation > Muscle Pain Syndromes

Myofascial Pain: Differential Diagnoses & Workup

Author: Jennifer E Finley, MD, FAAPMR, CIME, Consulting Physiatrist
Contributor Information and Disclosures

Updated: Aug 26, 2009

Differential Diagnoses

Fibromyalgia

Other Problems to Be Considered

Articular dysfunction requiring manual mobilization
Nonmyofascial trigger points
Radiculopathy

Workup

Laboratory Studies

  • No specific lab tests confirm a diagnosis of myofascial pain (MP), but lab tests can be helpful in looking for predisposing conditions, such as hypothyroidism, hypoglycemia, and vitamin deficiencies. Specific tests that may be helpful include complete blood count (CBC), chemistry profile, erythrocyte sedimentation rate (ESR), and levels of vitamins C, B-1, B-6, B-12, and folic acid. A thyrotropin level may be helpful if clinical features of thyroid disease are present.

Imaging Studies

  • Infrared or liquid crystal thermography can show increased blood flow, which is sometimes noted at trigger points. Other imaging studies are useful only to rule out other sources of pain generation.

Other Tests

  • Needle electromyography (EMG) examination of trigger points (TrPs) in humans and rabbits has shown high-voltage spike activity and spontaneous, low-voltage endplate noise, which is considered characteristic but not pathognomonic. Surface EMG has been used in experiment protocols to monitor muscle activity in TrPs. Ultrasonography has been used to visualize the LTR elicited by needle penetration.

Procedures

Trigger point (TrP) injections sometimes are performed with bupivacaine, etidocaine, lidocaine, saline, or sterile water.9,10,11,12 Dry needling is occasionally performed, without the injection of any substance.

Steroids may be used in areas possibly associated with inflammation, as in frozen shoulder. Botulinum toxin (BOTOX®) shows promise as a substance that can provide long-lasting relief.13,14,15,16 Its mechanism of action may be related to the blocking of acetylcholine release at the neuromuscular junction of the dysfunctional motor endplates. 

A report by Affaitati et al indicated that a topical anesthetic patch can also relieve myofascial pain, without the discomfort that can result from TrP injections.17 Patients in the study were separated into groups of 20, one of which was treated for 4 days with a lidocaine patch applied to each patient's trigger point (with patients receiving a total daily dose of 350 mg). The second group received a placebo patch, and the third group was treated with injections of 0.5% bupivacaine hydrochloride.

In members of the lidocaine patch and bupivacaine injection groups, the investigators found significant decreases and increases in, respectively, subjective symptoms and pain thresholds. Although the effects at muscle TrPs and target areas were more pronounced in the injected patients, the lidocaine patients experienced less therapy-related discomfort. Subjective symptoms and pain thresholds did not improve in the placebo group.

Histologic Findings

Contraction knots are a characteristic finding in trigger points, and tender, palpable nodules have been recognized since 1951.

More on Myofascial Pain

Overview: Myofascial Pain
Differential Diagnoses & Workup: Myofascial Pain
Treatment & Medication: Myofascial Pain
Follow-up: Myofascial Pain
References
Further Reading
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References

  1. Dorsher PT. Myofascial referred-pain data provide physiologic evidence of acupuncture meridians. J Pain. Jul 2009;10(7):723-31. [Medline].

  2. McPartland JM. Travell trigger points--molecular and osteopathic perspectives. J Am Osteopath Assoc. Jun 2004;104(6):244-9. [Medline]. [Full Text].

  3. Hong CZ, Simons DG. Pathophysiologic and electrophysiologic mechanisms of myofascial trigger points. Arch Phys Med Rehabil. Jul 1998;79(7):863-72. [Medline].

  4. Gerwin RD. A review of myofascial pain and fibromyalgia--factors that promote their persistence. Acupunct Med. Sep 2005;23(3):121-34. [Medline].

  5. Graff-Radford SB. Myofascial pain: diagnosis and management. Curr Pain Headache Rep. Dec 2004;8(6):463-7. [Medline].

  6. Simons DG, Travell JG, Simons LS. Travell and Simons' Myofascial Pain and Dysfunction: The Trigger Point Manual. 2nd ed. Baltimore, Md: Williams & Wilkins; 1999.

  7. Gerwin RD, Dommerholt J, Shah JP. An expansion of Simons' integrated hypothesis of trigger point formation. Curr Pain Headache Rep. Dec 2004;8(6):468-75. [Medline].

  8. Myburgh C, Larsen AH, Hartvigsen J. A systematic, critical review of manual palpation for identifying myofascial trigger points: evidence and clinical significance. Arch Phys Med Rehabil. Jun 2008;89(6):1169-76. [Medline].

  9. Hameroff SR, Crago BR, Blitt CD, et al. Comparison of bupivacaine, etidocaine, and saline for trigger-point therapy. Anesth Analg. Oct 1981;60(10):752-5. [Medline].

  10. Hong CZ. Lidocaine injection versus dry needling to myofascial trigger point. The importance of the local twitch response. Am J Phys Med Rehabil. Jul-Aug 1994;73(4):256-63. [Medline].

  11. Venâncio Rde A, Alencar FG, Zamperini C. Different substances and dry-needling injections in patients with myofascial pain and headaches. Cranio. Apr 2008;26(2):96-103. [Medline].

  12. Wreje U, Brorsson B. A multicenter randomized controlled trial of injections of sterile water and saline for chronic myofascial pain syndromes. Pain. Jun 1995;61(3):441-4. [Medline].

  13. Aoki KR. Evidence for antinociceptive activity of botulinum toxin type A in pain management. Headache. Jul-Aug 2003;43 Suppl 1:S9-15. [Medline].

  14. Lang AM. Botulinum toxin therapy for myofascial pain disorders. Curr Pain Headache Rep. Oct 2002;6(5):355-60. [Medline].

  15. Jeynes LC, Gauci CA. Evidence for the use of botulinum toxin in the chronic pain setting--a review of the literature. Pain Pract. Jul-Aug 2008;8(4):269-76. [Medline].

  16. Cheshire WP, Abashian SW, Mann JD. Botulinum toxin in the treatment of myofascial pain syndrome. Pain. Oct 1994;59(1):65-9. [Medline].

  17. Affaitati G, Fabrizio A, Savini A, et al. A randomized, controlled study comparing a lidocaine patch, a placebo patch, and anesthetic injection for treatment of trigger points in patients with myofascial pain syndrome: evaluation of pain and somatic pain thresholds. Clin Ther. Apr 2009;31(4):705-20. [Medline].

  18. Gam AN, Warming S, Larsen LH, et al. Treatment of myofascial trigger-points with ultrasound combined with massage and exercise--a randomised controlled trial. Pain. Jul 1998;77(1):73-9. [Medline].

  19. Lee SH, Chen CC, Lee CS, et al. Effects of needle electrical intramuscular stimulation on shoulder and cervical myofascial pain syndrome and microcirculation. J Chin Med Assoc. Apr 2008;71(4):200-6. [Medline].

  20. Srbely JZ, Dickey JP, Lowerison M, et al. Stimulation of myofascial trigger points with ultrasound induces segmental antinociceptive effects: a randomized controlled study. Pain. May 26 2008;[Medline].

  21. Flor H, Birbaumer N. Comparison of the efficacy of electromyographic biofeedback, cognitive- behavioral therapy, and conservative medical interventions in the treatment of chronic musculoskeletal pain. J Consult Clin Psychol. Aug 1993;61(4):653-8. [Medline].

  22. Birch S, Jamison RN. Controlled trial of Japanese acupuncture for chronic myofascial neck pain: assessment of specific and nonspecific effects of treatment. Clin J Pain. Sep 1998;14(3):248-55. [Medline].

  23. Leite FM, Atallah AN, El Dib R, et al. Cyclobenzaprine for the treatment of myofascial pain in adults. Cochrane Database Syst Rev. Jul 8 2009;CD006830. [Medline].

  24. Bendtsen L, Jensen R, Olesen J. Qualitatively altered nociception in chronic myofascial pain. Pain. May-Jun 1996;65(2-3):259-64. [Medline].

  25. Danto JB. Review of integrated neuromusculoskeletal release and the novel application of a segmental anterior/posterior approach in the thoracic, lumbar, and sacral regions. J Am Osteopath Assoc. Dec 2003;103(12):583-96. [Medline]. [Full Text].

  26. Facco E, Ceccherelli F. Myofascial pain mimicking radicular syndromes. Acta Neurochir Suppl. 2005;92:147-50. [Medline].

  27. Hsueh TC, Cheng PT, Kuan TS, et al. The immediate effectiveness of electrical nerve stimulation and electrical muscle stimulation on myofascial trigger points. Am J Phys Med Rehabil. Nov-Dec 1997;76(6):471-6. [Medline].

  28. Saggini R, Giamberardino MA, Gatteschi L, et al. Myofascial pain syndrome of the peroneus longus: biomechanical approach. Clin J Pain. Mar 1996;12(1):30-7. [Medline].

  29. Simons DG. Review of enigmatic MTrPs as a common cause of enigmatic musculoskeletal pain and dysfunction. J Electromyogr Kinesiol. Feb 2004;14(1):95-107. [Medline].

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Further Reading

Related eMedicine topics:
 Cervical Myofascial Pain
Fibromyalgia [Pediatrics: General Medicine]
Fibromyalgia [Physical Medicine and Rehabilitation]
Fibromyalgia [Rheumatology]
Massage, Traction, and Manipulation
Myofascial Pain in Athletes
Transcutaneous Electrical Nerve Stimulation

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Keywords

myofascial pain, myofascial, trigger point, myofascial pain, myofascial pain syndrome, trigger point pain, chronic myofascial pain, trigger point therapy, myofascial trigger point, myofascial trigger, trigger point injections, trigger pain, pain and myofascial, musclehãrten, myogeloses, osteochondrosis, myofascitis

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Contributor Information and Disclosures

Author

Jennifer E Finley, MD, FAAPMR, CIME, Consulting Physiatrist
Jennifer E Finley, MD, FAAPMR, CIME is a member of the following medical societies: American Academy of Medical Acupuncture, American Academy of Physical Medicine and Rehabilitation, and American Association of Neuromuscular and Electrodiagnostic Medicine
Disclosure: Allergan Honoraria Speaking and teaching

Medical Editor

Martin K Childers, DO, PhD, Associate Professor, Department of Neurology, Wake Forest University Health Services
Martin K Childers, DO, PhD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, American Congress of Rehabilitation Medicine, American Osteopathic Association, Christian Medical & Dental Society, and Federation of American Societies for Experimental Biology
Disclosure: Allergan pharma Consulting fee Consulting

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Patrick M Foye, MD, FAAPMR, FAAEM, Associate Professor of Physical Medicine and Rehabilitation, Co-Director of Musculoskeletal Fellowship, Co-Director of Back Pain Clinic, Director of Coccyx Pain Service (Tailbone Pain Service: www.TailboneDoctor.com), University of Medicine and Dentistry of New Jersey, New Jersey Medical School
Patrick M Foye, MD, FAAPMR, FAAEM is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, American Association of Neuromuscular and Electrodiagnostic Medicine, Association of Academic Physiatrists, and International Spine Intervention Society
Disclosure: Nothing to disclose.

CME Editor

Kelly L Allen, MD, Regional Medical Director, IMX-Medical Management Services
Disclosure: Nothing to disclose.

Chief Editor

Consuelo T Lorenzo, MD, Consulting Staff, Department of Physical Medicine and Rehabilitation, Alegent Health Care, Immanuel Rehabilitation Center
Consuelo T Lorenzo, MD is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation
Disclosure: Nothing to disclose.

 
 
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