{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,12]],"date-time":"2026-05-12T12:45:26Z","timestamp":1778589926347,"version":"3.51.4"},"reference-count":30,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2024,6,1]],"date-time":"2024-06-01T00:00:00Z","timestamp":1717200000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>Primary hyperthyroidism is a rarely diagnosed endocrinopathy in equids and there have been no previous reports of structural and functional cardiac changes associated with hyperthyroidism in these species. This case report investigates a 20-year-old mule gelding that presented for a three-month history of thin body condition despite polyphagia, with a heart murmur and elevated free and total thyroid hormone concentrations. On presentation, physical exam revealed a body condition score of two out of nine, persistent tachycardia, pansystolic heart murmur and firm bilateral ventral proximal cervical masses. Bloodwork confirmed markedly elevated free T4, total T4 and T3 concentrations. Echocardiogram demonstrated left ventricular concentric hypertrophy with increased ventricular and atrial systolic function. Bilateral thyroidectomy was performed under standing sedation without complications. Histopathology demonstrated adenocarcinoma of the left thyroid gland and multiple adenomas with osseous metaplasia within the right thyroid. The mule was supplemented with levothyroxine sodium two weeks post-op after a thyroid panel demonstrated undetectable concentrations. Polyphagia resolved following surgery and the mule began gaining weight. Echocardiographic changes improved but did not resolve at two years post-operative. Continued bi-annual follow up and monitoring of thyroid levels was recommended. This case represents the first documentation of hemodynamically relevant cardiac remodeling in an equid associated with primary hyperthyroidism.<\/jats:p>","DOI":"10.3390\/ani14111660","type":"journal-article","created":{"date-parts":[[2024,6,3]],"date-time":"2024-06-03T03:51:45Z","timestamp":1717386705000},"page":"1660","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Cardiac Disease Related to Primary Hyperthyroidism in a 20-Year-Old Mule"],"prefix":"10.3390","volume":"14","author":[{"given":"Kaitlin","family":"Brown","sequence":"first","affiliation":[{"name":"Department of Clinical Sciences, Cornell University, Ithaca, NY 14850, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7910-8740","authenticated-orcid":false,"given":"Elizabeth","family":"Williams Louie","sequence":"additional","affiliation":[{"name":"Department of Clinical Sciences, Cornell University, Ithaca, NY 14850, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0946-1893","authenticated-orcid":false,"given":"Toby","family":"Pinn-Woodcock","sequence":"additional","affiliation":[{"name":"Department of Clinical Sciences, Cornell University, Ithaca, NY 14850, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Erin","family":"Pearson","sequence":"additional","affiliation":[{"name":"Department of Clinical Sciences, Cornell University, Ithaca, NY 14850, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Garett B.","family":"Pearson","sequence":"additional","affiliation":[{"name":"Department of Clinical Sciences, Cornell University, Ithaca, NY 14850, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jacqueline","family":"Marr","sequence":"additional","affiliation":[{"name":"New Hampshire Veterinary Diagnostic Laboratory, University of New Hampshire, Durham, NH 03824, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6559-9585","authenticated-orcid":false,"given":"Eileen S.","family":"Hackett","sequence":"additional","affiliation":[{"name":"Department of Clinical Sciences, Cornell University, Ithaca, NY 14850, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Laura","family":"Rath Brown","sequence":"additional","affiliation":[{"name":"Midstate Veterinary Services, Cortland, NY 14045, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5545-5630","authenticated-orcid":false,"given":"Katharyn J.","family":"Mitchell","sequence":"additional","affiliation":[{"name":"Department of Clinical Sciences, Cornell University, Ithaca, NY 14850, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,6,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"475","DOI":"10.1111\/j.1939-1676.1998.tb02153.x","article-title":"Hyperthyroidism associated with a thyroid adenocarcinoma in a 21-year-old gelding","volume":"12","author":"Ramirez","year":"1998","journal-title":"J. Vet. Intern. Med."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1051","DOI":"10.2460\/javma.2000.217.1051","article-title":"Hemithyroidectomy in a horse with confirmed hyperthyroidism","volume":"217","author":"Alberts","year":"2000","journal-title":"J. Am. Vet. Med."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1253","DOI":"10.1111\/j.1939-1676.2008.0169.x","article-title":"The use of propylthiouracil for treatment of hyperthyroidism in a horse","volume":"22","author":"Tan","year":"2008","journal-title":"J. Vet. Intern. Med."},{"key":"ref_4","first-page":"1189","article-title":"Response to thyrotropin-releasing hormone (TRH) in a horse with hyperthyroidism associated with a functional thyroid adenoma","volume":"60","author":"Costello","year":"2019","journal-title":"Can. Vet. J."},{"key":"ref_5","first-page":"211","article-title":"The incidence and types of disease of the thyroid gland of adult horses","volume":"78","author":"Schlotthauer","year":"1931","journal-title":"J. Am. Vet. Med."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1016\/S0021-9975(08)80270-8","article-title":"The frequent occurrence of thyroid tumours in aged horses","volume":"110","author":"Dalefield","year":"1994","journal-title":"J. Comp. Pathol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"86","DOI":"10.1111\/vsu.12744","article-title":"Standing thyroidectomy in 10 horses","volume":"47","author":"Marcatili","year":"2018","journal-title":"Vet. Surg."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"60","DOI":"10.14797\/mdcj-13-2-60","article-title":"Hyperthyroidism and the heart","volume":"13","author":"Osuna","year":"2017","journal-title":"Methodist DeBakey Cardiovasc. J."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"723","DOI":"10.1016\/j.cvsm.2007.05.011","article-title":"Cardiovascular and renal manifestations of hyperthyroidism","volume":"37","author":"Syme","year":"2007","journal-title":"Vet. Clin. N. Am. Small Anim."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"319","DOI":"10.1007\/s003600050080","article-title":"The effect of thyroid hormones on the aerobic development of locomotor and cardiac muscles in the barnacle goose","volume":"167","author":"Deaton","year":"1997","journal-title":"J. Comp. Physiol. B"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"H283","DOI":"10.1152\/ajpheart.1987.252.2.H283","article-title":"Increased myocardial \u03b2-receptors and adrenergic responses in hyperthyroid pigs","volume":"252","author":"Hammond","year":"1987","journal-title":"Am. J. Physiol.-Heart Circ. Physiol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"H1429","DOI":"10.1152\/ajpheart.2000.278.5.H1429","article-title":"Thyroid hormone-induced overexpression of functional ryanodine receptors in the rabbit heart","volume":"278","author":"Jiang","year":"2000","journal-title":"Am. J. Physiol.-Heart Circ. Physiol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1694","DOI":"10.1172\/JCI112488","article-title":"Effects of thyroid hormone on cardiac size and myosin content of the heterotropically transplanted rat heart","volume":"77","author":"Klein","year":"1986","journal-title":"J. Clin. Investig."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"400","DOI":"10.1177\/1098612X16643252","article-title":"2016 AAFP guidelines for the management of feline hyperthyroidism","volume":"18","author":"Carney","year":"2016","journal-title":"J. Fel. Med. Surg."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"68","DOI":"10.14740\/cr1034","article-title":"Thyroid and cardiovascular disease: A focused review on the impact of hyperthyroidism in heart failure","volume":"11","author":"Khan","year":"2020","journal-title":"Cardiol. Res."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"501","DOI":"10.1177\/1098612X15588797","article-title":"Survival in cats with primary and secondary cardiomyopathies","volume":"18","author":"Spalla","year":"2016","journal-title":"J. Fel. Med. Surg."},{"key":"ref_17","unstructured":"Hart, K., Durham, A., Frank, N., McGowan, C., Schott, H., and Stewart, A. (2023). Recommendations for the Diagnosis and Management of Pituitary Pars Intermedia Dysfunction (PPID), Equine Endocrinology Group."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"866","DOI":"10.1111\/jvim.13928","article-title":"Accuracy and Precision of Noninvasive Blood Pressure in Normo-, Hyper-, and Hypotensive Standing and Anesthetized Adult Horses","volume":"30","author":"Heliczer","year":"2016","journal-title":"J. Vet. Intern. Med."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1111\/j.2042-3306.1995.tb04902.x","article-title":"Selected echocardiographic parameters and right sided pressures of the mule","volume":"27","author":"Tucker","year":"1995","journal-title":"Equine Vet. J."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"404","DOI":"10.1016\/S0737-0806(07)80485-0","article-title":"Echocardiographic and right-sided cardiac pressure comparison of the mule and horse","volume":"15","author":"Tucker","year":"1995","journal-title":"J. Equine Vet. Sci."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1241","DOI":"10.1111\/jvim.14368","article-title":"Echocardiographic assessment of left atrial size and function in warmblood horses: Reference intervals, allometric scaling and agreement of different echocardiographic variables","volume":"30","author":"Huesler","year":"2016","journal-title":"J. Vet. Intern. Med."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"504","DOI":"10.1111\/jvim.15968","article-title":"Echocardiographic assessment of left ventricular size and systolic function in Warmblood horses using linear measurements, area-based indices, and volume estimates: A retrospective database analysis","volume":"35","author":"Berthoud","year":"2021","journal-title":"J. Vet. Intern. Med."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"747","DOI":"10.1292\/jvms.13-0488","article-title":"Identification and preservation of the parathyroid gland during total thyroidectomy in dogs with bilateral thyroid carcinoma: A report of six cases","volume":"77","author":"Fukui","year":"2015","journal-title":"J. Vet. Med. Sci."},{"key":"ref_24","first-page":"740","article-title":"Disorders of the thyroid gland","volume":"Volume 2","author":"Nelson","year":"2014","journal-title":"Small Animal Internal Medicine"},{"key":"ref_25","unstructured":"(2022, January 25). Hyperthyroidism, Available online: https:\/\/www.ncbi.nlm.nih.gov\/books\/NBK537053\/."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"24","DOI":"10.1053\/j.semnuclmed.2013.08.007","article-title":"Thyroid scintigraphy in veterinary medicine","volume":"44","author":"Daniel","year":"2014","journal-title":"Semin. Nucl. Med."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"472","DOI":"10.1097\/00000658-199605000-00003","article-title":"Parathyroid autotransplantation during thyroidectomy. Results of long-term follow-up","volume":"223","author":"Olson","year":"1996","journal-title":"Ann. Surg."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"3","DOI":"10.14797\/mdcvj.197","article-title":"The cardiovascular effects of hyperthyroidism","volume":"6","author":"Nabbout","year":"2010","journal-title":"Methodist DeBakey Cardiovasc. J."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"482","DOI":"10.3389\/fendo.2019.00482","article-title":"Hypertension in thyroid disorders","volume":"10","author":"Berta","year":"2019","journal-title":"Front. Endocrinol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"470","DOI":"10.1161\/01.CIR.102.4.470","article-title":"Left ventricular hypertrophy: Pathogenesis, detection and prognosis","volume":"102","author":"Lorell","year":"2000","journal-title":"Circulation"}],"container-title":["Animals"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-2615\/14\/11\/1660\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T14:52:15Z","timestamp":1760107935000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-2615\/14\/11\/1660"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,6,1]]},"references-count":30,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2024,6]]}},"alternative-id":["ani14111660"],"URL":"https:\/\/doi.org\/10.3390\/ani14111660","relation":{},"ISSN":["2076-2615"],"issn-type":[{"value":"2076-2615","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,6,1]]}}}