Thyroid Function Tests in the Dog: Recent Concepts

Ferguson, Duncan C.

doi:10.1016/s0195-5616(84)50081-3

Cited by 20 publications

(7 citation statements)

References 54 publications

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“…A comparable value is only achieved with the detection of low fT4 concentrations by the expensive and time-consuming equilibrium dialysis technique. 35 In conclusion, thyroid sonography enabled us to establish a diagnosis in dogs with decreased thyroid hormone concentrations of unknown etiology. It is a reliable diagnostic tool to differentiate between canine hypothyroidism and ESS and an effective complement to established routine diagnostic tests.…”

Section: Discussionmentioning

confidence: 89%

“…To determine the diagnostic value of sonography in canine hypothyroidism, sensitivity, specificity, and accuracy were calculated for the different sonographic variables as suggested by Ferguson et al 35 Sensitivity was defined as the fraction of dogs that actually were hypothyroid that were labeled as hypothyroid by sonography. Specificity was defined as the fraction of dogs that actually were euthyroid that were labeled as euthyroid by sonography.…”

Section: Sonographymentioning

confidence: 99%

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Thyroid Sonography as an Effective Tool to Discriminate between Euthyroid Sick and Hypothyroid Dogs

Reese

Breyer

Deeg

et al. 2005

Veterinary Internal Medicne

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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 ϭ 87), dogs with euthyroid sick syndrome (n ϭ 26), thyroglobulin autoantibody-positive (TgAA-positive, n ϭ 30) hypothyroid dogs, and TgAA-negative (n ϭ 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 Ͻ .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 TgAApositive and TgAA-negative hypothyroid dogs was significantly lower (P Ͻ .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.

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Section: Discussionmentioning

confidence: 89%

Section: Sonographymentioning

confidence: 99%

Thyroid Sonography as an Effective Tool to Discriminate between Euthyroid Sick and Hypothyroid Dogs

Reese

Breyer

Deeg

et al. 2005

Veterinary Internal Medicne

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“…The basis of the diagnosis is based on little or no elevation in the serum T 4 level following TRH administration. Since T 3 serum levels are less influenced by thyroidal T 3 secretion (Chastain, 1982;Ferguson, 1984), the change in the serum T 3 level following TRH administration is inconsistent and of little diagnostic value (Evinger et al, 1985;Li, 1986). The lack of any significant elevation in T 3 levels after TRH administration in the dogs in group H parallelled the T 4 response and confirmed that these animals had primary hypothyroidism.…”

Section: Discussionmentioning

confidence: 99%

“…A considerable amount of the circulating T 3 is derived from peripheral deiodination of thyroxine in the kidney and the liver (Kaptein et al 1990). A decrease in the peripheral production of T 3 may result from several non-thyroid illnesses or very rarely from a primary lesion at the converting enzyme level (Ferguson, 1984(Ferguson, , 1988.…”

Section: Discussionmentioning

confidence: 99%

Impaired local deiodination of thyroxine to triiodothyronine in dogs with symmetrical truncal alopecia

et al. 1994

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Thyroid dysfunction causes certain dermatological alterations in dogs. Insufficient delivery of thyroid hormone to the skin may originate not only from inadequate thyroid function but also from impaired local activation of thyroxine in the target organ. Thyroid parameters and deiodination were investigated in healthy dogs (group C) and in dogs with cutaneous lesions associated with hypothyroidism (group H) or with a low-T3 syndrome (group LT). The ability of the skin to convert T4 to T3 was impaired in both groups H and LT but not in the controls. It is concluded that impaired local deiodination may contribute to skin problems in dogs.

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“…Therefore, although it also has intrinsic metabolic activity, T4 has been called a ''prohormone'' because of its conversion to the more potent T3 in a step regulated by peripheral tissues. 7,14,[21][22][23][24] Peripheral deiodination of T4 into T3 occurs intracellularly. The identification of 3 distinct types of 5Ј-deiodinase (5Ј-D) enzymes has underscored the importance of the regulation of T3 production from T4 in individual tissues.…”

Section: Metabolism Of Thyroid Hormonementioning

confidence: 99%

Influence of Drugs on Thyroid Function in Dogs

Daminet¹,

Ferguson²

2003

J Vet Int Med

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Several drugs can affect thyroid function test results in humans and eventually lead to an erroneous evaluation of thyroid function. These medications can alter the synthesis, secretion, transport, or metabolism of thyroid hormones. Some drugs also directly inhibit the hypothalamic-pituitary-thyroid axis. The effects of drugs on thyroid function in dogs have long been underestimated and have most likely contributed to the overdiagnosis of hypothyroidism in this species. This manuscript 1st reviews pertinent thyroid physiology followed by an overview of drugs for which the effects on canine thyroid function have been studied. The effects of glucocorticoids, propranolol, sulfonamides, phenobarbital, potassium bromide, and nonsteroidal anti-inflammatory agents (NSAIDs) on canine thyroid function are summarized here. Knowledge of the potential effect of these medications on thyroid function should contribute to a more reliable interpretation of thyroid function test results in dogs.

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Thyroid Function Tests in the Dog: Recent Concepts

Cited by 20 publications

References 54 publications

Thyroid Sonography as an Effective Tool to Discriminate between Euthyroid Sick and Hypothyroid Dogs

Thyroid Sonography as an Effective Tool to Discriminate between Euthyroid Sick and Hypothyroid Dogs

Impaired local deiodination of thyroxine to triiodothyronine in dogs with symmetrical truncal alopecia

Influence of Drugs on Thyroid Function in Dogs

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