title: Thyroid sonography as an effective tool to discriminate between euthyroid sick and hypothyroid dogs.
abstract: The diagnosis of canine hypothyroidism and its differentiation from euthyroid sick syndrome still is a major diagnostic challenge. In this study, ultrasonography was shown to be an effective tool for the investigation of thyroid gland diseases. Healthy control dogs (n = 87), dogs with euthyroid sick syndrome (n = 26), thyroglobulin autoantibody-positive (TgAA-positive, n = 30) hypothyroid dogs, and TgAA-negative (n = 23) hypothyroid dogs were examined by thyroid ultrasonography. Maximal cross sectional area (MCSA), thyroid volume, and echogenicity were measured. Statistical analysis identified highly significant (P < .001) differences between euthyroid and hypothyroid dogs both in thyroid volume and in MCSA, whereas no significant differences in thyroid size were detected between healthy euthyroid dogs and dogs with euthyroid sick syndrome. In euthyroid and euthyroid sick dogs, parenchymal echotexture was homogeneous and hyperechoic, whereas relative thyroid echogenicity of both TgAA-positive and TgAA-negative hypothyroid dogs was significantly lower (P < .001). When using arbitrarily chosen cutoff values for relative thyroid volume, MCSA, and echogenicity, thyroid volume especially was found to have highly specific predictive value for canine hypothyroidism. In summary, the data reveal that thyroid sonography is an effective ancillary diagnostic tool to differentiate between canine hypothyroidism and euthyroid sick syndrome.
authors.affiliation: Institute of Veterinary Anatomy, University of Munich, D-80539 Munich, Germany. sven.reese@lmu.de
authors.forename: Sven
authors.initials: S
authors.lastname: Reese
authors.forename: Ulrike
authors.initials: U
authors.lastname: Breyer
authors.forename: Cornelia
authors.initials: C
authors.lastname: Deeg
authors.forename: Wilfried
authors.initials: W
authors.lastname: Kraft
authors.forename: Bernd
authors.initials: B
authors.lastname: Kaspers
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000000981:diagnostic imaging*; D004285:Dogs; D005067:Euthyroid Sick Syndromes / Q000000981:diagnostic imaging / Q000662:veterinary*; D005260:Female; D007037:Hypothyroidism / Q000000981:diagnostic imaging / Q000662:veterinary*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013961:Thyroid Gland / Q000000981:diagnostic imaging*; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology; D013974:Thyroxine / Q000097:blood; D014463:Ultrasonography
chemical_list: D013973:Thyrotropin-Releasing Hormone; D013974:Thyroxine