BACKGROUND
Headache ranks among the top ten most disabling conditions worldwide.1 Tension type headache is the most frequent primary headache and is characterized by bilateral, non-throbbing, mild to moderate pain of the head and neck that is not exacerbated by routine physical activity.2 According to the International Headache Society (IHS), there are 2 distinct types of tension type headache. Episodic tension type headaches (sub-classified as infrequent or frequent) occur between 1-14 days per month. Less common, chronic tension-type headaches (CTTH) are present on greater than or equal to 15 days per month.2 Population-based studies suggest a lifetime prevalence of 42%1 with three times more work days lost when compared to migraine headaches.3The IHS criteria for diagnosis of CTTH includes (1) headache occurring ≥15 days per month on average for >3 months (2) lasting hours to days and (3) demonstrating at least two of the following four characteristics: bilateral location, pressing or tightening (non-pulsating) quality, mild or moderate intensity, not aggravated by routine physical activity.2
The onset of episodic headache can occur due to peripheral tissue irritation with central pain mechanisms underlying the evolution to CTTH.4-6 Patients with CTTH demonstrate greater headache intensity and frequency compared to those with episodic tension type headache, indicating temporal summation of noxious afferent input.7 Recurrent, low-frequency nociceptor stimulation progressively sensitizes peripheral nerve terminals and spinal dorsal horn neurons related to the neck and shoulder region, contributing to the formation and maintenance of myofascial trigger points (MTrP) in patients with CTTH.8,9 Previous studies have demonstrated neck and shoulder MTrPs, along with surrounding soft tissues including tendons, ligaments, and fascia may reproduce the symptoms associated with CTTH.10-14
Simons and Travell defined a MTrP as a hyperirritable spot within a taut band of a skeletal muscle that is painful on compression, stretch, overload, or contraction with referred pain perceived distant from the hyperirritable spot.15 Although a systematic review found no high-quality studies reporting the inter-rater reliability of identifying the location of a MTrP in a symptomatic muscle, good reliability was reported for diagnostic signs including local tenderness (k= 0.22 to 1.0) and pain recognition (k= 0.57 to 1.0).16 Advanced imaging techniques like sonoelastography and magnetic resonance elastography appear to contribute to the objective identification of MTrPs.17,18
The integrated hypothesis of MTrP formation proposed by Simons, speculates excessive acetylcholine release at the neuromuscular junction leads to sustained contraction of sarcomeres, local ischemia and an ATP driven ‘energy crisis’. The resultant hypoxic state of the muscle induces secretion of inflammatory chemical mediators followed by the antidromic release of neuropeptides from local nerve endings, lowering pH levels and sensitizing neural pathways that contribute to the formation of MTrPs.19 Active MTrPs are clinically associated with spontaneous pain (without palpation or manual compression) in the immediate surrounding tissue and/or distant, referred sites. In contrast, latent MTrPs elicit local or referred pain only upon palpation and are not recognized as familiar pain to the patient.20 Both active and latent MTrPs can provoke tissue dysfunction characterized by reduced range of motion, muscle fatigue and altered activation patterns.21,22
Approximately 70% of patients with CTTH appear to experience muscle spasms in the cervical region.23,24 More specifically, pathophysiological changes in the muscular activity of the sub-occipitals, sternocleidomastoid, upper trapezius, and levator scapulae have been recognized in the development of CTTH.13,25
Levator scapulae syndrome (LSS) is a musculoskeletal disorder, characterized by pain and stiffness in the upper thoracic and cervical regions, with limited cervical range of motion and tenderness to palpation at the medial aspect of the superior angle of the scapula.26-28 Distal levator scapulae muscle belly and teno-osseous attachment tenderness has been reported in patients with LSS and may play a role in the development of “enthesopathy resulting from sustained MTrP tension”.15 Increased heat emission has been measured from the medial aspect of the superior angle of the scapula in more than 60% of patients diagnosed with LSS, suggestive of an active metabolic process.28 Notably, this specific region is the anatomical correlate for the enthesis attachment in LSS. Following mechanical damage, tissue repair responses and vessel ingrowth have been observed.29 Similar to tendons in disrepair, pain and tenderness at the enthesis is associated with increased vascularity on color imaging.30
Physical therapy is one of the most commonly used non-pharmacological approaches in the management of CTTH and can include manipulation and mobilization, postural control, exercise, soft tissue release, and dry needling.31,32 Dry needling is a skilled treatment technique that uses solid filiform needles inserted into MTrPs, tendons, teno-osseous structures and other soft tissues.33-35Dry needling has been found to significantly improve headache frequency, MTrP tenderness, cervical range of motion and health-related quality of life in patients with CTTH by providing a more comprehensive treatment approach than exercise and manual therapy alone.36-38
This case report describes the history, physical examination findings, specific treatments, and outcomes of a patient with CTTH associated with LSS and highlights the importance of a thorough palpatory examination, including both myofascial and teno-osseous structures. Considering the documented effects of postural stress on musculoskeletal dysfunction in the workplace, such as decreased ability to concentrate, increased sedentary behavior associated with the use of technological devices may lead to a higher prevalence of tension type headache in the future.39-45