Alterations in Metabolic Status and Headshaking Behavior Following Intravenous Administration of Hypertonic Solutions in Horses with Trigeminal-Mediated Headshaking.
Authors: Sheldon Shara, Aleman Monica, Costa Lais, Santoyo A Cristina, Howey Quinn, Madigan John
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Trigeminal-mediated headshaking remains one of the most intractable behavioural and welfare problems in equine practice, driven by aberrant firing of the trigeminal nerve that produces violent head jerking and often ends in euthanasia. Since acid-base status and electrolyte balance influence neuronal excitability, researchers administered three different intravenous solutions to six affected horses in a randomised crossover trial: 5% dextrose, 7.5% hypertonic saline, and 8.4% sodium bicarbonate, measuring both headshaking behaviour and venous blood parameters over two hours. Only sodium bicarbonate treatment produced a clinically meaningful response, with greater than 50% reduction in headshaking rate, alongside significant alkalemia, metabolic alkalosis, and elevated standard base excess—changes that persisted for the duration of monitoring. The hypertonic saline and dextrose solutions caused only minor, transient alterations to electrolyte and acid-base parameters, with no substantive effect on headshaking behaviour, suggesting the body's robust homeostatic mechanisms rapidly counteracted these interventions. Whilst these preliminary findings suggest alkalinising therapy warrants further investigation as a potential therapeutic avenue, the authors appropriately caution that the small sample size and transient nature of observed changes limit immediate clinical application, and that future work should explore sustained or repeated dosing protocols and identify which specific electrolyte disturbances might most effectively modulate trigeminal nerve threshold.
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Practical Takeaways
- •Sodium bicarbonate IV administration may offer a therapeutic option for trigeminal-mediated headshaking cases, though further investigation is needed to understand the mechanism and optimize protocols
- •Dextrose and hypertonic saline showed minimal effects on headshaking behavior, making them unsuitable as targeted therapies for this condition despite electrolyte changes
- •The transient nature of blood parameter changes indicates that acute metabolic manipulation has limited durability; longer-term or repeated dosing protocols may warrant investigation
Key Findings
- •Sodium bicarbonate (HB) infusion produced >50% reduction in headshaking rate, the only treatment showing significant behavioral effect
- •HB treatment induced metabolic alkalosis with blood pH and HCO3− outside physiologic range, while DS and HS caused minimal blood composition changes
- •Time and breed influenced headshaking rates independent of treatment
- •All blood composition changes were transient, suggesting homeostatic regulation limited treatment efficacy