The time course of lactate and endocrine changes in dogs suffering from dog bite wounds.

Background: The stress response after acute trauma in humans and animals has been well-recognised in the literature. However, data on temporal changes in endocrine parameters after acute trauma in previously healthy dogs are scant.

Objective: To longitudinally track endocrine variables and lactate concentrations in dogs with canine bite wounds.

Method: Prospective study involving 20 dogs hospitalised after being bitten by another dog. Serum cortisol, thyroxine (total T4), thyrotropin (TSH), and lactate concentrations were measured on admission and every 8 hours after the recorded bite incident, for a 72-hour period.

Results: Median cortisol concentration was markedly elevated on admission (314.6 nmol/L; IQR 229.3-369.6) but returned to within the reference interval by 16 hours post-bite (99.5 nmol/L; IQR 48.7-225.4) and reached a nadir at 48 hours post-bite (38.5 nmol/L; IQR 32.1-115.9). Median total T4 concentration was within the reference interval on admission (20.6 nmol/L; IQR 12.7-27.9) but decreased below the reference interval by 8 hours (11.0 nmol/L; IQR 5.0-14.1) and reached a nadir 16 hours postbite (7.0 nmol/L; IQR 2.9-19.7), before gradually increasing after 64 hours to reach the reference range by 72 hours. The median TSH concentrations remained within the reference interval throughout the study period. Median lactate concentration was mildly elevated on admission (3.0 mmol/L; IQR 2.0-3.9).

Conclusion: This study produced novel data on the temporal relationships of the hypothalamic-pituitary-adrenal and hypothalamicpituitary- thyroidal axes alterations after an acute traumatic insult in dogs.