Excerpt from Muscle Contraction Tension Headache

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Background

Tension-type headache (TTH) represents one of the most costly diseases because of its very high prevalence. TTH is the most common type of headache, and it is classified as episodic (ETTH) or chronic (CTTH). It had various ill-defined names in the past including tension headache, stress headache, muscle contraction headache, psychomyogenic headache, ordinary headache, and psychogenic headache.

The International Headache Society (IHS) defines TTH more precisely and differentiates between the episodic and the chronic types. The following is a modified outline of the IHS diagnostic criteria:

Episodic tension-type headache

• At least 10 previous headaches fulfilling the following criteria; number of days with such headache fewer than 15 per month

• Headaches lasting from 30 minutes to 7 days

• At least 2 of the following pain characteristics:
  • Pressing/tightening (nonpulsating) quality

  • Mild or moderate intensity (may inhibit but does not prohibit activities)

  • Bilateral location

  • No aggravation from climbing stairs or similar routine physical activity

• Both of the following:
  • No nausea or vomiting

  • Photophobia and phonophobia absent or only one present

• Secondary headache types not suggested or confirmed

Chronic tension-type headache

• Average headache frequency of more than 15 days per month for more than 6 months fulfilling the following criteria

• At least 2 of the following pain characteristics:
  • Pressing/tightening (nonpulsating) quality

  • Mild or moderate intensity (may inhibit but does not prohibit activities)

  • Bilateral location

  • No aggravation from climbing stairs or similar routine physical activity

• Both of the following:
  • No vomiting

  • No more than one of the following: nausea, photophobia, or phonophobia

• Secondary headache types not suggested or confirmed

Pathophysiology

Pathogenesis of TTH is complex and multifactorial, with contributions from both central and peripheral factors. In the past, various mechanisms including vascular, muscular (ie, constant overcontraction of scalp muscles), and psychogenic factors were suggested. The more likely cause of these headaches is believed now to be abnormal neuronal sensitivity and pain facilitation, not abnormal muscle contraction.

Various evidence suggests that, like migraine, TTH is associated with exteroceptive suppression (ES2), abnormal platelet serotonin, and decreased cerebrospinal fluid beta-endorphin. In one study, plasma levels of substance P, neuropeptide Y, and vasoactive intestinal peptide were found to be normal in patients with CTTH and unrelated to the headache state.

Several concurrent pathophysiologic mechanisms may be responsible for TTH; according to Jensen, extracranial myofascial nociception is one of them. Headache is not related directly to muscle contraction, and possible hypersensitivity of neurons in the trigeminal nucleus caudalis has been suggested.

Bendtsen described central sensitization at the level of the spinal dorsal horn/trigeminal nucleus due to prolonged nociceptive inputs from pericranial myofascial tissues. The central neuroplastic changes may affect regulation of peripheral mechanisms and can lead to increased pericranial muscle activity or release of neurotransmitters in myofascial tissues. This central sensitization may be maintained even after the initial eliciting factors have been normalized, resulting in conversion of ETTH into CTTH.

Further research is necessary to understand and clarify the mechanisms of TTH. Research may lead to the development of more specific and effective management in the future.

Frequency

United States

TTH is the most common primary headache syndrome.

International

Rasmussen et al reported a lifetime prevalence of TTH of 69% in men and 88% in women in the Danish population. The patient may experience more than one primary headache syndrome. In one study by Ulrich et al, the 1-year prevalence of TTH was the same among individuals with and without migraine.

Sex

Women are slightly more likely to be affected than men.

• The female-to-male ratio for TTH is approximately 1.4:1.
• In CTTH, female preponderance is 1.9:1.

Age

TTH can occur at any age, but onset during adolescence or young adulthood is common. It can begin in childhood.

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