Pain perception, blood pressure levels, and peripheral benzodiazepine receptors in patients followed for differentiated thyroid carcinoma: a longitudinal study in hypothyroidism and during hormone treatment.
BACKGROUND
Elevated blood pressure levels that are associated with hypalgesia and hypothyroidism have major influences on the cardiovascular system. The potential modulation of pain sensitivity by thyroid hormones is largely undetermined. Moreover, a few experimental studies show that peripheral benzodiazepine receptors (PBRs), which may be altered in hypothyroidism, seem to be related with pain perception.


METHODS
Dental pain threshold and tolerance were evaluated in 19 patients followed for differentiated thyroid carcinoma (1) in severe short-term hypothyroidism (phase 1) and (2) during thyroid stimulating hormone-suppressive LT4 treatment (phase 2). PBR expression (cytofluorimetric evaluation) on peripheral blood mononuclear cells was also investigated in the 2 phases.


RESULTS
Pain perception differed throughout the study, the dental pain threshold was higher in phase 1 (P<0.05) whereas pain tolerance was higher but not significantly (P=0.07). Although the systolic blood pressure was higher during hypothyroidism (P<0.01), no relationship was found between blood pressure changes and pain sensitivity variations. Moreover, the multiple regression analysis showed an independent association of the clinical phase with pain sensitivity (r=-2.61, P=0.029), while accounting for systolic blood pressure. The intensity of PBRs was significantly higher in the first phase of the study (P=0.047) whereas the ratio did not significantly differ. However, no relationship was observed between pain sensitivity and PBRs.


CONCLUSIONS
In conclusion, in athyreotic patients, the pain sensitivity is related to the thyroid status and is independent of the increase in blood pressure induced by thyroid hormone deprivation. The PBRs do not seem to have major influence on pain sensitivity changes in hypothyroidism.
Guasti
Luigina
L
Department of Clinical Medicine, University of Insubria, Varese, Italy. luigina.guasti@uninsubria.it
Marino
Franca
F
Cosentino
Marco
M
Cimpanelli
Mariagrazia
M
Rasini
Emanuela
E
Piantanida
Eliana
E
Vanoli
Paolo
P
De Palma
Diego
D
Crespi
Chiara
C
Klersy
Catherine
C
Maroni
Lorenzo
L
Loraschi
Anna
A
Colombo
Cristina
C
Simoni
Cinzia
C
Bartalena
Luigi
L
Lecchini
Sergio
S
Grandi
Anna M
AM
Venco
Achille
A
D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology*; D002291:Carcinoma, Papillary / Q000503:physiopathology* / Q000523:psychology* / Q000628:therapy; D003782:Dental Pulp / Q000502:physiology; D004558:Electric Stimulation; D023381:Endpoint Determination; D005260:Female; D005434:Flow Cytometry; D006358:Hot Temperature; D006801:Humans; D007037:Hypothyroidism / Q000139:chemically induced / Q000150:complications* / Q000503:physiopathology*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism; D009619:Nociceptors / Q000187:drug effects / Q000502:physiology; D010146:Pain / Q000209:etiology / Q000523:psychology*; D010147:Pain Measurement / Q000187:drug effects*; D011312:Pressure; D011963:Receptors, GABA-A / Q000187:drug effects*; D015203:Reproducibility of Results; D013963:Thyroid Hormones / Q000009:adverse effects* / Q000627:therapeutic use; D013964:Thyroid Neoplasms / Q000503:physiopathology* / Q000523:psychology* / Q000628:therapy; D013965:Thyroidectomy
D011963:Receptors, GABA-A; D013963:Thyroid Hormones