Thyroid‐stimulating hormone and total thyroxine concentrations in euthyroid, sick euthyroid and hypothyroid dogs

Abstract

Canine thyroid-stimulating hormone (cTSH) was measured in a variety of clinical cases (n = 72). The cases were classified as euthyroid, sick euthyroid, hypothyroid or hypothyroid on nonthyroidal therapy on the basis of their history, clinical signs, laboratory results (including total thyroxine concentrations and, where indicated, thyroid-releasing hormone [TRH] stimulation tests) and response to appropriate therapy. Additional samples were taken during some of the TRH stimulation tests to measure the response of cTSH concentrations following TRH administration. A reference range (0 to 0.41 ng/ml) was calculated from the basal concentrations of cTSH in a group of 41 euthyroid dogs. Six of nine cases of confirmed hypothyroidism had basal cTSH concentrations above the reference range, whereas the remainder were within the normal range. One of these three remaining cases was a pituitary dwarf and did not show a rise in cTSH concentration following TRH stimulation. In contrast, only one of a group of six hypothyroid dogs that had been on non-thyroidal treatment within the previous four weeks had increased concentrations of basal cTSH. This study also found that five of a group of 16 dogs with sick euthyroid syndrome had increased cTSH concentrations. It was concluded that cTSH measurements are a useful additional diagnostic test in cases of suspected hypothyroidism in dogs but that dynamic testing is still required to confirm the diagnosis of hypothyroidism.

Avaliação terapêutica e posológica da levotiroxina sódica em cães com hipotiroidismo primário adquirido

“…Quando a suspeita clínica do hipotiroidismo é grande e a síndrome do eutiroideo doente é descartada, a mensuração isolada do T4 livre tem um forte valor diagnóstico, pois é o teste que apresenta maior especiϐicidade (94%) e acurácia (95%), quando avaliado isoladamente (Ramsey & Herrtage 1997, Scott-Moncrieff 2010. A média de T4 livre observada em nossa casuística foi de 0,21±0,14ng/dL (VR =0,7-2,6).…”

Evaluation of Canine Serum Thyrotropin (TSH) Concentration: Comparison of Three Analytical Procedures

“…Some workers reported precision values very similar or even higher than those obtained in the present study. 3,9 However, other authors reported significantly better precision with the immunoradiometric assay. 13 Only 1 study has been performed using the chemiluminescent assay, and the analytic variability was higher than that obtained in the present study.…”

“…8,9,11 For this reason, stimulation tests using thyroid-stimulating hormone (TSH, Thyrotropin) or thyroid-releasing hormone have been proposed. 4,7 Recently, an assay to measure canine TSH has been developed.…”

“…3,6,8,10 However, further studies should be implemented, and most of the researchers agree that the assay could be helpful in the evaluation of hypothyroid dogs. 3,7,9,11,13 Three procedures can be used in the analysis of canine TSH: immunoradiometric assay, enzyme immunometric assay, and chemiluminescent immunometric assay. Most of the results published to date have been obtained with the immunoradiometric assay, and very little information about the other two methods is available.…”

Comparación del perfil lipídico y del perfil tiroideo en caninos adultos obesos vs. caninos adultos normales

“…Igualmente, en niños obesos se encontraron niveles elevados de TSH y una correlación significativa de esta con el índice de masa corporal y los niveles de insulina (Dekelbab et al, 2010). Se debe tener en cuenta que los valores del perfil lipídico (Osorio & Giraldo, 1999;Osorio et al, 2012a) y del perfil tiroideo (Ramsey et al, 1997;Melián-Limiñana et al, 1999;Matamoros et al, 2002;Ramírez-Benavides & Osorio, 2009) pueden ser más bajos que los de otros estudios, y esto se deba posiblemente a la utilización de diferentes técnicas o de diferentes kits para la determinación de cada una de las variables estudiadas.…”