Sanjeev Arora MD

56 Pages·2017·2.98 MB·English

MYOFASCIAL PAIN
Focus on the Upper Extremity
Benson Daitz MD & Brian M. Shelley MD
UNM Family & Community Medicine
Resident School, April 2018
FINANCIAL DISCLOSURES
•None.
OBJECTIVES: MPS
After this session, participants will be able to:
• Define myofascial pain syndrome (MPS)
• Identify common presentations of MPS in the upper
extremity
• Perform a trigger point injection in a myofascial trigger
point.
MYOFASCIAL PAIN SYNDROME (MPS)
• Characterized by the development of myofascial trigger points
(TrP or MTrP) that are locally tender when active.
• Refer pain through specific patterns to other areas of the
body.
• Due to many causes like trauma, arthritis, deconditioning.
• Trigger points are usually associated with a taut band, a ropey
thickening of the muscle tissue.
• Diagnosis depends on history, exam, and specialized manual
palpation.
• Local twitch response may be seen in palpation and treatment
• Fascia also very important.

JANET TRAVELL MD
•A TrP is a “hyperirritable spot, usually within a
taut band of skeletal muscles or in the muscle’s
fascia, that is painful on compression and that can
give rise to characteristic phenomena.”
MPS: Mechanism (Travell)
• The “integrated hypothesis” includes:
• Spine
• Muscle
• NMJ
• Abnormalities at the neuro-muscular junction:
↑ ACh production, depolarization
↑ Sustained shortening of sarcomeres
↑ Energy demand, release of sensitizing
substances, leading to…
↑ ACh production (BTXA blocks release)

SHAH
• Compared to carefully matched controls, people with neck pain
secondary to active TrPs had significantly elevated local levels of
• endogenous substance P (SP)
• calcitonin gene-related peptide (CGRP)
• bradykinin (BK)
• serotonin/5-hydroxytryptamine (5-HT)
• norepinephrine (NE)
• tumor necrosis factor alpha (TNF-α)
• interleukin 1-beta (IL-1β)
Shah JP, Danoff JV, Desai M, et al. Biochemicals associated with pain and
inflammation are elevated in sites near to and remote from active
myofascial trigger points. Arch Phys Med Rehabil (2008);89:16-23.
SHAH
•At motor endplate (distal axon):
•↑CGRP → ↑Ach → ↓AchE activity
•Leads to increased ACh receptors and activity,
and persistent focal muscle fiber contraction
•TrPs have spontaneous electrical activity (SEA),
or dysfunctional endplate potential of extrafusal
(skeletal) muscle fibers