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Presumptive nonthyroidal illness syndrome in critically ill foals
Author(s) -
HIMLER M.,
HURCOMBE S. D. A.,
GRIFFIN A.,
BARSNICK R. J.,
RATHGEBER R. A.,
MACGILLIVRAY K. C.,
TORIBIO R. E.
Publication year - 2012
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/j.2042-3306.2011.00480.x
Subject(s) - sepsis , medicine , foal , hormone , euthyroid sick syndrome , thyroid , critically ill , septic shock , systemic inflammatory response syndrome , clinical significance , physiology , thyroid hormones , biology , genetics
Summary Reasons for performing the study: Hypothalamic‐pituitary‐thyroid (HPT) axis dysfunction is associated with morbidity and mortality in critically ill people. To date, investigations of HPT axis in critically ill foals are limited. Objectives: To document the occurrence of low thyroid hormone concentrations (presumptive nonthyroidal illness syndrome; NTIS) in critically ill newborn foals and investigate whether NTIS is associated with severity of disease and outcome. Hypothesis: NTIS occurs frequently in foals with sepsis and is associated with sepsis score and outcome. Reverse T3 (rT3) concentrations will be increased in septic foals and highest in nonsurvivors. Methods: Thyroid hormones (total and free thyroxine [TT4 and fT4], total and free tri‐iodothyronine [TT3 and fT3], reverse T3 [rT3]) were prospectively measured in healthy, sick nonseptic and septic foals. Clinical and laboratory information was retrieved from the medical records. Hormones were measured by validated radioimmunoassays. Results: Concentrations of all thyroid hormones except rT3 (P = 0.69) were decreased in septic and sick nonseptic foals (P<0.01). Reductions in hormone concentrations were associated with an increased sepsis score (P<0.01). Nonsurviving septic foals had lower TT4, fT4, TT3 and fT3 concentrations than surviving septic foals (P<0.01). rT3 concentrations were higher in nonsurviving septic premature foals than surviving septic premature foals (P<0.05). Conclusions: NTIS (euthyroid sick syndrome) is frequently observed in critically ill and premature foals, and associated with severity of disease and mortality. Potential relevance: More research is needed to better understand the mechanism of this finding and determine whether manipulation of the HPT axis or thyroid replacement therapy could be beneficial.