Effect of Dexamethasone on Resting Blood Lactate Concentrations in Horses

Abstract

BackgroundBlood lactate concentration is a marker of tissue perfusion and helps guide therapeutic interventions in critically ill horses. In both humans and dogs, administration of corticosteroids can increase blood lactate concentration, leading to type B hyperlactatemia. This effect could be a consequence of the impact of corticosteroids on glucose metabolism.ObjectivesTo investigate the effects of daily IM dexamethasone administration on blood lactate and glucose concentrations in horses.AnimalsNine healthy adult horses.MethodsA randomized, blinded, controlled, cross‐over study design was used. Horses were randomly assigned to 1 of 2 groups, either receiving 0.05 mg/kg of dexamethasone IM or an equivalent volume of saline, daily for 7 days. Blood was collected to determine lactate and glucose concentrations at baseline, 2 hours after the daily injections and 24 hours after the last injection.ResultsDexamethasone treatment had a statistically significant effect on lactate (P = .006) and glucose (P = .033) concentrations. The least squares mean lactate concentration was 0.93 mmol/L (95% CI: 0.87–0.99) in the dexamethasone group compared to 0.71 mmol/L (95% CI: 0.70–0.73) for the saline group. A positive relationship between blood lactate and glucose concentrations was identified, with a 0.07 mmol/L (95% CI: 0.05–0.09) increase in lactate concentration per unit increase in glucose (P < .0001) concentration.Conclusions and Clinical ImportanceDexamethasone induces statistically significant increases in blood lactate and glucose concentrations in healthy horses. Awareness of the potential for corticosteroids to induce type B hyperlactatemia might be important in the management of critically ill horses receiving dexamethasone.

Influence of endocrine disease on l‐lactate concentrations in blood of ponies

“…33,34 A similar association between obesity, ID, and increased blood l-lactate concentrations could therefore be present in equids leading to the hypotheses that blood l-lactate concentrations are higher in ponies with increased autumnal ACTH concentrations or evidence of ID and would correlate with measures of endocrine health. 35,36 However, contrary to findings in people, a negative correlation between l-lactate concentrations and average BCS 32 was detected in ponies in the present study and no correlation with baseline insulin, insulin concentrations 60 minutes after an OST, adiponectin, triglycerides, or ACTH concentrations could be established. There might be several explanations why results of our study did not support the hypotheses.…”

“…38 Although a positive relationship between blood glucose and l-lactate concentrations was identified and increases in both variables were timely associated in the study in horses, it could not be determined whether hyperglycemia was a prerequisite for the development of hyperlactatemia. 35 All ponies in our study were clinically healthy and hyperglycemia was not detected in any of the ponies. This suggests that any endocrine abnormalities were well compensated and not severe enough to result in clinical signs.…”

“…Steroid hormones appear to have a major influence on l‐lactate metabolism and free cortisol concentrations are increased in overweight and obese equids 37 . Administration of exogenous corticosteroids to cardiac surgery patients and healthy horses decreased insulin sensitivity and increased blood glucose and l‐lactate concentrations 35,38 . In the study involving human cardiac patients, increased blood l‐lactate concentrations appeared to be dependent on the presence of hyperglycemia 38 .…”

Glucocorticoid treatment in horses with asthma: A narrative review

“…Use of dexamethasone (0.05 mg/kg IM q24h, 7 days) also results in a clinically irrelevant increase in blood lactate. 127 Glucocorticoids alter calcium metabolism by increasing urinary excretion and decreasing gastrointestinal absorption 129 along with an inhibition of calcium release from bones. 130 Because administration of GC to human patients is associated with osteoporosis, this effect was investigated in pony foals where prolonged treatment (>3 months) with dexamethasone (0.005-0.05 mg/kg q24h IM) led to osteonecrosis.…”

“…Use of dexamethasone (0.05 mg/kg IM q24h, 7 days) also results in a clinically irrelevant increase in blood lactate. 127 …”