Evaluation of the Combined Dexamethasone Suppression/Thyrotropin‐Releasing Hormone Stimulation Test for Detection of Pars Intermedia Pituitary Adenomas in Horses

Abstract

The combined DEX/TRH test was more sensitive than either of its component tests and had a high NPV, but was not as specific as the TRH component alone (92%). The DEX/TRH test should be used to screen older horses for PIPA.

Correlation of Pituitary Histomorphometry with Adrenocorticotrophic Hormone Response to Domperidone Administration in the Diagnosis of Equine Pituitary Pars Intermedia Dysfunction

“…Similar pathologic findings were previously described in horses and ponies with or without clinical evidence of PPID. 7,11,14,22,28 Adherence to the grading scheme used in this study resulted in good concordance between pathologists and a strong correlation with domperidone-evoked plasma ACTH concentrations. The scheme allowed ranking of hyperplasia in pituitary glands based on the presence or absence of certain histologic features, but measurement of PI area in histologic sections provided a continuous variable and more objective means to quantify the degree of hyperplasia.…”

“…However, in a study of 42 donated horses, 17 of which had adenomas or microadenomas in the PI, one also had a microadenoma in the pars anterior. 14 Milder hyperplastic changes were also common in the pars anterior in this study, but multinodular hyperplasia of the equine pars anterior has been recognized as a common but nonfunctional lesion in older horses, 15 and histologic grading in the current study was based on changes in the PI except for the 1 horse with a pars anterior adenoma. Lesions in the pars anterior of other horses in this study did not correlate strongly with pituitary histologic grade, ACTH assay results, or clinical evidence of PPID.…”

“…Postmortem histologic evaluation of pituitary glands has been used to validate clinical diagnostic tests for PPID, 14 although a recent study revealed only moderate concordance among pathologists or correlation between pituitary lesions and antemortem test results. 19 The purposes of the study reported here were to determine the effect of domperidone administration on plasma ACTH concentration in horses with or without clinical signs of PPID and to correlate the plasma ACTH response to domperidone with postmortem histologic and morphometric features of the pituitary gland.…”

Tumors of the endocrine system in the horse - clinical pathology

“…Während das ECS in der älteren Literatur (Pauli et al 1974) als seltene Erkrankung beschrieben wird, zeigt sich neueren Untersuchungen zufolge, dass mit geeigneten Testverfahren, z.B. mittels direkter Bestimmung der Plasma-ACTH-Konzentration (Schott II 2002, Frank et al 2006, Einspanier und Gottschalk 2010, und verbesserter Information der Tierärzte diese Erkrankung sehr viel häufiger erkannt wird (Schott II 2002, Hoppen et al 2006). …”

Epidemiologic investigation on the Pituitary Pars Intermedia Dysfunction of horses in Germany – evaluation of a questionnaire

“…Da Hypertrichose pathognomonisch zu sein scheint, erfolgt die Diagnosestellung häufig anhand dieses Symptoms (Schott 2006). In einer Studie konnte gezeigt werden, dass das Vorhandensein von Hypertrichose eine größere diagnostische Aussagekraft hat, als verschiedene endokrinologische Tests (Frank et al 2006a). Neben der Hypertrichose sind vor allem die Fettumverteilung und die chronische Hufrehe von Bedeutung (Grenager 2010).…”