Trigger Points & Headache: Chicken or Egg, Which Comes First?

The term myofascial trigger point (MTrP) was popularized in the 1950s and is defined as a hyperirritable spot in skeletal muscle that is associated with a hypersensitive palpable nodule in a taut band (Travell J et al, 1952).

The Role of TrPs Remains Unknown

80 years having passed, the pathogenesis of TrPs and their role in muscle pain remain unknown (Jay P, et al, 2015).

Suppose TrPs do exist, thousands of trials shew that inserting a needle not directly into TrP produce similar effect. The landmark study on dry needling (Lewit K, 1979) pricked only 2 TrPs out of 14 targeted structures. The latter included ligaments, tendons, bones, and teno-osseus insertion sites. All induced pain relief.

In the last few decades, an extensive body of literature, including randomized controlled trials, supports the insertion of dry needles throughout the body at non-TrP sites for the purpose of reducing pain and disability.

It is noteworthy that even some enthusiastic TrP advocators, such as American physiotherapist Jan Dommenhold, a leading expert in TrP dry needling, acknowledge “that there has not been a study to demonstrate the minimum essential features of the TrP needed to identify it for diagnosis and treatment purposes” (Dommerholt J et al, 2015).

TrP-Pain Theory: Circular Reasoning

In 2015, Australian osteopathic researchers Quinter et al argued that the construct of muscle pain caused by TrPs is nothing but a conjecture coming from circular reasoning: TrPs cause pain; pain leads to TrPs (Quinter JL et al, 2015).

In circular reasoning fallacy, the evidence used to support a claim is just a repetition of the claim itself. For example: “The President of our country is a good leader (claim), because he is the leader of our country (supporting evidence)”.

Are Trigger Points Associated with Headache?

MTrPs have been proposed to take part in primary headache disorders and other chronic pain conditions (Olesen J, 1991).

In 2018, 5 researchers from Denmark published a review (Do, T.P. et al.2018) which examined the relationship between myofascial trigger points and headache (migraine and tension-type headache). The review included 14 trials reported in 2006 – 2017.

The review found:

• MTrPs are very frequent in both migraine patients and tension-type headache (TTH) patients compared to healthy controls.
• Active MTrPs are rarely found in control groups.
• However, the results about whether the amount of MTrPs is correlated with the frequency and intensity of headache attacks are highly conflicting. About half of the trials say yes, another half say no.

Based on the results, the authors concluded:

• Whether myofascial trigger points contribute to an increased migraine burden in terms of frequency and intensity is unclear.

Can Headache Cause Trigger Points?

The review further identified studies that in patients with migraine-fibromyalgia comorbidity, migraine attacks exacerbate fibromyalgia symptoms. In other words, the headache attacks lead to more tender points on the body . The authors consider this finding suggests a top-down central sensitization (Giamberardino MA, et al, 2015). That is, pain perceived by brain (CNS) leads to more tender points on the body regions outside the brain and spinal cord (PNS). In other words, from top to bottom.

The review also looked at a trial which found that the number of active myofascial trigger points is higher in adults compared with adolescents regardless of no significant association with headache parameters.

The authors believe this suggests that myofascial trigger points are accumulated over time as a consequence of headache rather than a cause of the headache.

In short, headache may cause trigger points.

Relationship between TrPs & Pain : 2 Possible Explanations

The authors of the review proposed 2 possible explanations for the relationship between TrPs and headache: bottom-up model and top-down model.

The bottom-up model states that increased peripheral nociceptive transmission sensitizes the central nervous system to lower the threshold for perceiving pain while the top-down model suggests these changes are already present in central nervous system (Do, T.P. et al.2018).

In relation to myofascial trigger points, a bottom-up model would suggest that increased nociceptive transmission from myofascial trigger points lowers the threshold for perceiving pain (red). A top-down model would suggest that central sensitization may contribute to the occurrence of myofascial trigger points rather than the other way around (blue) (Do, T.P. et al.2018).

How Does Circular Reasoning Fallacy Work?

A circular reasoning fallacy consists of an argument that starts with a premise (A) and moves to a conclusion (B), where A is logically equivalent to B either explicitly or implicitly. In other words, both the premise and conclusion rely on the other’s truthfulness (Kassiani Nikolopoulou, 2023):

• A is true, because B is true
• B is true, because A is true

By the end of a circular reasoning fallacy, the argument will have come full circle, without actually having proven anything. It will use the fact that A can prove B and vice versa.

This happens because the speaker already believes the claim is true. People may commit circular reasoning fallacy unintentionally because they are convinced of their own assumptions and take them as given.

Chicken or Egg, Which Came First?

Trigger points cause headache, or headache causes trigger points? Chicken or egg, which comes first? Is there anyone in the medicine world who knows the answer?

References

Do, T.P. et al. Myofascial trigger points in migraine and tension-type headache. J Headache Pain 19, 84. 2018

Dommerholt J, Gerwin RD (2015). "A critical evaluation of Quintner et al: missing the point" (PDF). J Bodyw Mov Ther. 19 (2): 193–204.

Giamberardino MA, et al (2015) Impact of migraine on fibromyalgia symptoms. J Headache Pain. 17:28

Jay P Shah? et al., , Myofascial Trigger Points Then and Now: A Historical and Scientific Perspective, PM R.. 2015 Jul;7(7):746-761.

Kassiani Nikolopoulou, Circular Reasoning Fallacy, August 21, 2023. scribbr.com

Lew PC, Lewis J, Story I. Inter-therapist reliability in locating latent myofascial trigger points using palpation. Man Ther. 1997 May;2(2):87-90.

Lewit K. The needle effect in the relief of myofascial pain. Pain. 1979;6(1):83–90.

Olesen J (1991) Clinical and pathophysiological observations in migraine and tension-type headache explained by integration of vascular, supraspinal and myofascial inputs. Pain 46:125–132

Quintner JL, Bove GM, Cohen ML , 2015, "A critical evaluation of the trigger point phenomenon". Rheumatology (Oxford). 54 (3): 392–399

Sciotti VM, Mittak VL, DiMarco L, Ford LM, Plezbert J, Santipadri E,

Travell J, Simons D (1952) The myofascial genesis of pain. Postgrad Med 11:434–452

Wigglesworth J, Ball K. Clinical precision of myofascial trigger point location in the trapezius muscle. Pain. 2001 Sep;93(3):259-266.

Trough E, et al, Variability of criteria used to diagnosis myofascial trigger point pain syndrome-evidence from a review of the literature. Clin J Pain.2007;23:278–286.

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