Pain Intensity, Illness Duration, and Protein Catabolism in Temporomandibular Disorder Patients with Chronic Muscle Pain
- Autores: Neil R. McGregor, Mariann Zerbes, Suzanne H. Niblett, R. Hugh Dunstan, K. A. Roberts, Henry L. Butt, Iven Klineberg
- Localización: Journal of Oral & Facial Pain and Headache, ISSN-e 2333-0376, ISSN 2333-0384, Vol. 17, Nº. 2, 2003, págs. 112-124
- Idioma: inglés
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Resumen
Aims: To investigate whether the duration of chronic pain in temporomandibular disorder (TMD) patients is associated with a net depletion of amino acids, and a distinct process from pain intensity.
Methods: Twenty-nine patients defined by the research diagnostic criteria/TMD as having Type 1a muscle pain (TMD1A group), and 34 age- and sex-matched control subjects, were assessed for variation in urinary organic and amino acid excretion by gas chromatography-mass spectrometry.
Results: The TMD1A patients' mean pain intensity, assessed on a visual analog scale (VAS), was 5.4 (95% confidence limits: 4.5 to 6.3), TMD1A illness duration was 5.0 ± 1.2 (SD) years, number of body areas with pain/subject was 6.3 ± 2.4 (range 0 to 10), and symptom prevalence from the Symptom Check List-90-Revised (SCL-90-R) was 25.5 ± 11.3 symptoms/subject, which was higher than the controls (5.2 ± 5.0 symptoms/subject, P < .001). TMD1A patient illness duration was positively correlated with symptom prevalence and body pain distribution, and all were independent of pain intensity. The TMD1A patients had: (1) an increased tyrosine:leucine ratio; and (2) reduced leucine concentrations (both P < .001), which suggests deregulated catabolism. Pain intensity was associated with: (1) changes in the multivariate urinary metabolite excretion patterns (P < .001); (2) reduced leucine concentrations (P < .001); and (3) increases in total urinary metabolites (P < .04), and in 2 unidentified molecules, UM28 (P < .001) and CFSUM1 (P < .002). TMD1A illness duration was associated with lower (1) urinary metabolite concentrations and (2) succinic acid and combined glutamine + glutamic acid levels, suggesting a progressive depletion of metabolite reserves.
Conclusion: In TMD1A patients, total amino acid excretion was positively correlated with pain intensity and negatively correlated with illness duration, which indicated that illness duration was associated with a different set of metabolic anomalies compared with those identified for pain intensity.
