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