Plasma-Ionized Magnesium in Hospitalized Horses with Gastrointestinal Disorders and Systemic Inflammatory Response Syndrome.
Authors: Sanmartí Julia, Armengou Lara, Troya-Portillo Lucas, Robles-Guirado José Ángel, Bassols Anna, Ríos José, Jose-Cunilleras Eduard
Journal: Animals : an open access journal from MDPI
Summary
Magnesium imbalances in critically ill horses have received little research attention despite their potential clinical significance. Sanmartí and colleagues conducted a prospective observational study of 75 hospitalised horses with various gastrointestinal and systemic disorders, measuring ionised plasma magnesium (iMg) on admission and stratifying cases by diagnosis, presence of systemic inflammatory response syndrome (SIRS), and survival outcome, alongside a control group of 26 healthy horses. Horses with obstructive gastrointestinal disease demonstrated notably lower iMg concentrations than controls (0.44 versus 0.56 mmol/L; p=0.001), with hypomagnesemia present in 47% of obstructive cases compared to only 4% of controls—a clinically meaningful difference suggesting specific pathophysiological involvement in this disease category. Inflammatory and ischaemic gastrointestinal disorders showed intermediate magnesium derangement, whilst the presence of SIRS alone did not reliably predict magnesium status, and importantly, hypomagnesemia was not significantly associated with mortality in this equine population, contrasting with findings in human critically ill patients. For practitioners managing equine colic, particularly obstructive lesions, these findings highlight the value of assessing ionised magnesium status as part of initial diagnostic work-up; however, the lack of mortality association suggests magnesium abnormalities may be a marker of disease severity rather than a direct driver of poor outcomes warranting aggressive supplementation.
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Practical Takeaways
- •Horses admitted with obstructive gastrointestinal disease should be screened for hypomagnesemia on presentation, as nearly half may be affected
- •While hypomagnesemia is more prevalent in horses with gastrointestinal obstruction, it does not appear to influence survival outcomes in hospitalized horses
- •Magnesium supplementation decisions in equine gastrointestinal cases should not be based primarily on mortality risk, distinguishing equine management from human critical care protocols
Key Findings
- •Horses with obstructive gastrointestinal lesions had significantly lower ionized magnesium (0.44 mmol/L) compared to controls (0.56 mmol/L; p=0.001)
- •47% of horses with obstructive lesions presented with hypomagnesemia on admission versus only 4% of controls (p=0.001)
- •Hypomagnesemia was present to a lesser extent in inflammatory and ischemic gastrointestinal groups
- •Unlike human ICU patients, hypomagnesemia in hospitalized horses was not associated with mortality