title: In vivo evidence of altered skeletal muscle blood flow in chronic tension-type headache.
abstract: Painful impulses from tender pericranial muscles may play a major role in the pathophysiology of chronic tension-type headache. Firm evidence for peripheral muscle pathology as a cause of muscle pain and chronic headache is still lacking. Using a microdialysis technique, we aimed to estimate in vivo blood flow and interstitial lactate concentrations in the trapezius muscle at rest and during static exercise in patients with chronic tension-type headache and in healthy subjects. We recruited 16 patients with chronic tension-type headache and 17 healthy control subjects. Two microdialysis catheters were inserted into the trapezius muscle (on the non-dominant side) of subjects, and dialysates were collected at rest, 15 and 30 min after the start of static exercise (10% of maximal force) and 15 and 30 min after the exercise was completed. All samples were coded and analysed blind. The primary endpoints were to detect a difference between patients and controls in changes of muscle blood flow and the interstitial lactate concentration from baseline to exercise and post-exercise periods. The increase in muscle blood flow from baseline to exercise and post-exercise periods was significantly lower in patients than controls (P = 0.03). There was no difference in resting blood flow between patients and controls (P = 0.43). Resting interstitial concentration of lactate did not differ between patients (2.51 +/- 0.18 mM; mean +/- standard error of the mean) and controls (2.35 +/- 0.23 mM, P = 0.57). There was no difference in change in interstitial lactate from baseline to exercise and post-exercise periods between patients and controls (P = 0.38). The present study provides in vivo evidence of decreased blood flow in response to static exercise in a tender muscle in patients with chronic tension-type headache. We suggest that, because of increased excitability of neurones in the CNS, the central interpretation and response to normal sensory input are altered in patients with chronic tension-type headache. This may lead to enhanced sympathetically mediated vasoconstriction and thereby a decreased blood flow in response to static exercise.
authors.affiliation: Department of Neurology, Glostrup Hospital, University of Copenhagen, Denmark. ashina@dadlnet.dk
authors.forename: M
authors.initials: M
authors.lastname: Ashina
authors.forename: B
authors.initials: B
authors.lastname: Stallknecht
authors.forename: L
authors.initials: L
authors.lastname: Bendtsen
authors.forename: J F
authors.initials: JF
authors.lastname: Pedersen
authors.forename: H
authors.initials: H
authors.lastname: Galbo
authors.forename: P
authors.initials: P
authors.lastname: Dalgaard
authors.forename: J
authors.initials: J
authors.lastname: Olesen
mesh_terms: D000293:Adolescent; D000328:Adult; D015444:Exercise; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D017551:Microdialysis / Q000379:methods; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000378:metabolism; D012039:Regional Blood Flow; D018781:Tension-Type Headache / Q000209:etiology / Q000503:physiopathology*; D014463:Ultrasonography
chemical_list: D019344:Lactic Acid