Background: Quantitative thermotests evaluate small diameter afferents but thermal thresholds may not be significantly different in PNP patients with and without pain.
Objective: To determine thermal and thermal pain thresholds, and pain estimation after suprathreshold stimuli, in upper and lower limbs in patients with PNP, or CNS lesions, with and without pain.
Methods: Patients with PNP (N = 60), and CNS lesions (N = 26) with sensory symptoms, with and without pain, were recruited and compared to controls (N = 13). Thermal thresholds (average x3) were obtained from the thenar eminence, lateral leg 10 cm above the ankle and tarsal area with a 3x3cm thermode (TSA-Medoc). Pain estimations (0–10) to nociceptive thermal stimuli (5 sec 20 °C, 5 °C, 40 °C and 45 °C) were recorded.
Results: Cold and warm thresholds were lower in controls compared to all patient groups (p < 0.001). Cold and heat pain thresholds were lower in healthy controls compared to all groups (p = 0.001) except for patients with CNS pathology without pain. Only cold threshold was significantly higher in patients with painful PNP.
(p = 0.05) compared to painless PNP. Thermal and thermal pain thresholds were otherwise similar in the other patient groups. Pain estimation for cold was higher in patients compared to controls but not statistically significant.
Conclusions: Patients with PNP or CNS pathology display significantly thermal and thermal pain hypoesthesia with a tendency to thermal hyperalgesia with suprathreshold stimuli. Cold hypoesthesia was the only parameter distinguishing painful from painless PNP.
*Fondecyt 1120339: LAcevedo, GBarraza, MCampero, JLCastillo, GCavada, RGuiloff, J Honeyman, RHughes, JMMatamala, EMullins, POrellana, CRamírez, HRojas, ISazunic, RVerdugo.
© 2015 Published by Elsevier Inc.