In vivo evidence of altered skeletal muscle blood flow in chronic tension‐type headache

Open Access
Publisher Website
Google Scholar
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.