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Altered quantitative sensory testing outcome in subjects with opioid therapy
Lucy Chen1, Charlene Malarick, Lindsey Seefeld
1MGH Center for Translational Pain Research, Department of Anesthesia and Critical Care, WACC 324, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
Pain
|February 25, 2009
Summary
Opioid-induced hyperalgesia (OIH) may decrease pain threshold in patients on opioid therapy. Quantitative sensory testing (QST) revealed reduced heat pain threshold and increased pain summation in these patients, suggesting OIH is clinically assessable.
Area of Science:
- Pain research
- Neuroscience
- Clinical pain assessment
Background:
- Preclinical studies suggest opioids can paradoxically decrease pain thresholds, a phenomenon known as opioid-induced hyperalgesia (OIH).
- The clinical characteristics and diagnostic markers of OIH in patients undergoing opioid therapy remain unclear.
- Understanding OIH is crucial for managing acute and chronic pain effectively.
Purpose of the Study:
- To investigate the clinical features of OIH using quantitative sensory testing (QST).
- To compare pain perception and temporal summation in patients with and without opioid therapy.
- To explore correlations between QST findings and clinical factors in opioid-treated patients.
Main Methods:
- A quantitative sensory testing (QST) protocol was employed in an office-based setting.
- Three groups were studied: healthy controls (no pain/opioids), chronic pain patients (no opioids), and chronic pain patients (on opioids).
- Thermal stimulation assessed pain threshold, pain tolerance, and temporal summation of second pain; correlations with opioid dose, duration, type, pain duration, and gender were examined.
Main Results:
- Patients on opioid therapy (Group 3) exhibited a significantly decreased heat pain threshold compared to controls (Group 1) and non-opioid pain patients (Group 2).
- Group 3 also showed exacerbated temporal summation of second pain in response to thermal stimuli.
- No significant differences in cold or warm sensation were observed among the groups.
- Daily opioid dose strongly correlated with decreased heat pain threshold and increased temporal summation in Group 3.
Conclusions:
- Decreased heat pain threshold and exacerbated temporal summation of second pain are potential characteristic QST changes in patients receiving opioid therapy.
- These findings suggest that QST is a valuable clinical tool for assessing opioid-induced hyperalgesia (OIH).
- Further research can elucidate the clinical implications of these QST findings in pain management.
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