Cortisol and adrenocorticotropic hormone concentrations in horses with systemic inflammatory response syndrome

Abstract

Background Plasma adrenocorticotropic hormone (ACTH) and serum cortisol concentrations increase with illness‐associated stress. Dynamics of plasma ACTH and serum cortisol concentrations in adult horses with systemic illness are undocumented. Hypothesis/Objective To determine whether ACTH and cortisol concentrations and the ACTH/cortisol ratio vary with survival, the presence of systemic inflammatory response syndrome (SIRS), or ischemic gastrointestinal lesions at admission, or throughout hospitalization. Animals One hundred fifty‐one adult horses. Methods Prospective study measuring serum cortisol and plasma ACTH at admission and on days 2, 4, and 6 of hospitalization. Horses were grouped by outcome (survival, SIRS status, number of SIRS criteria [SIRS score], SIRS severity group, and the presence of an ischemic lesion). Differences between groups and over time for ACTH, cortisol, and ACTH/cortisol ratio were investigated with a mixed effect model. Receiving operator characteristic curves and odds ratios were calculated for survival and ischemia. Results In all groups, ACTH, cortisol, and ACTH/cortisol ratio significantly decreased over time (P < .0001). ACTH, cortisol, and ACTH/cortisol ratio were higher at admission in nonsurvivors, and ACTH and cortisol were higher in horses with ischemic lesions (P < .01). Horses with ACTH above reference interval at admission were 6.10 (2.73‐13.68 [95% confidence interval]) times less likely to survive (P < .0001). No significant difference in ACTH, cortisol, and ACTH/cortisol ratio between horses with different SIRS status, scores, or groups were detected, although nonsurvivors had a higher SIRS score (P < .0001). Conclusions and Clinical Importance Pituitary and adrenal responses are altered in nonsurviving horses and those with an ischemic gastrointestinal lesion.

Effects of administration of ascorbic acid and low‐dose hydrocortisone after infusion of sublethal doses of lipopolysaccharide to horses

“…Furthermore, CIRCI has been documented in adult horses with SIRS, with diagnosis based on increased ACTH : cortisol ratios rather than delta cortisol. 23 Treatment with AA did not improve the cortisol response compared to placebo controls, suggesting that either the dose of AA was inadequate to decrease illness severity or that AA is ineffective in mitigating CIRCI in horses.…”

“…[18][19][20][21][22] Similarly, adult horses with SIRS typically present with increased serum cortisol concentrations and increased ACTH : cortisol ratios. 23 Ascorbic acid (AA) has potential for treating sepsis. Antioxidant effects of AA include scavenging of ROS and activation of other scavengers, including α-tocopherol.…”

Equine pituitary pars intermedia dysfunction: Identifying research priorities for diagnosis, treatment and prognosis through a priority setting partnership

“…However, uncertainty remains regarding test accuracy for PPID diagnosis in the presence of factors that may affect ACTH levels ( Table 3 , question E), such as concurrent disease (particularly insulin dysregulation), stress [ 56 ] and pain [ 57 ]. In referral hospital populations, a number of acute conditions have been reported to result in elevations of ACTH [ 57 , 58 ]. To date, these pre-analytical factors have not been evaluated in a population of PPID cases.…”

“…To date, these pre-analytical factors have not been evaluated in a population of PPID cases. However, the high proportion of systemically ill horses with ACTH concentrations above the upper limit of the reference interval at hospital admission [ 58 ] indicates that it is important to consider these factors when interpreting basal plasma ACTH concentration for the diagnosis of PPID in practice. The second question encompassed respondents’ uncertainly regarding the relative importance of endocrine laboratory test results and observed clinical signs.…”

Changes Associated with the Peri-Ovulatory Period, Age and Pregnancy in ACTH, Cortisol, Glucose and Insulin Concentrations in Mares

“…The hypothalamo–pituitary–adrenocortical (HPA) axis is the main control of the neurological and endocrine mechanisms, as it integrates external and internal stimuli. Several studies have identified the role of external environmental factors, such as season or diet, on adrenocorticotropic hormone (ACTH) secretion, as well as the role of critical illness on the HPA axis’ function [ 1 , 2 , 3 ]. There are, however, limited data available regarding the role of physiological internal factors.…”