Microdialysis Evaluation of Blood Flow, Lactate, and Glucose in Active Trigger Points of Tension-Type Headache Patients and Latent Trigger Points in Healthy Muscle.

Abstract

Objective: To assess nutritive blood flow, lactate, and glucose within active and latent TrPs compared to non-TrP muscle.

Design: Case-controlled observational study.

Setting: A University-based Clinical and Translational Research Center (CTRC).

Participants: Active TrPs were identified through palpation of the upper trapezius muscle of individuals with episodic or chronic tension-type headache (TTH). Latent TrPs and muscle without TrPs were identified in age- and sex-matched subjects without a history of headache.

Interventions: Not applicable.

Main outcome measures: Nutritive blood flow, and interstitial lactate and glucose concentrations were determined at 12-20-minute intervals over 160 minutes through microdialysis sampling of interstitial fluid.

Results: A total of 64 individuals participated in the study. Subjects were 33.8±10.8y, 64.1% female, and 73.4% white, with no statistical differences between active, latent, and no TrP groups on demographic or baseline variables (p>0.05). Subjects with TTH reported a median of 4 headaches/month and had experienced headaches for a median of 120 months. Active TrPs exhibit higher nutritive blood flow than anatomically matched no TrP muscle (p=0.026) but were not different from latent TrPs (p=0.554). There were no global differences between the three groups for lactate (p=0.329) or glucose (p=0.231).

Conclusions: The present study provides in vivo evidence of higher nutritive blood flow in active TrPs from individuals with TTH but no difference in lactate and glucose compared to non-TrP muscle. Our data does not support the TrP as a tightly contracted, ischemic region within skeletal muscle. Interventions designed to relax muscle contraction or increase blood flow may have limited benefits in alleviating active trigger points.