The Use of Magnesium Sulphate and Morphine Vs. Morphine-Only in Irukandji Syndrome: A Retrospective Review of Ambulance Data

Introduction In 2006, the Queensland Ambulance Service (QAS) approved the use of magnesium sulphate for the management of patients with Irukandji syndrome (IS). The aim of this study was to compare pain scores and hypertensive (systolic BP ≥140 mmHg and/or diastolic BP ≥90 mmHg) patients who received intravenous morphine as their treatment (morphine group) over those who received a combination of intravenous morphine and magnesium (magnesium group). Methods A retrospective case review of all IS patients attended by the QAS between 2007 and 2014. A search of the QAS electronic data base found 112 patients had IS. Analyses in IBM SPSS v.22 was undertaken to determine the outcome in final pain scores and blood pressure between the two groups. Results Pain reduction was statistically different (F=29.18; p<.01), between the morphine group and the magnesium group with mean numerical pain scores post-treatment of 4.91 (95% CI: 4.02–5.81) and 2.21 (95% CI: 1.66–2.76) respectively. There was a lower frequency of patients in the magnesium group who remained hypertensive on arrival at a medical facility, with a significant difference between mean arterial BP of 101 mmHg (95% CI: 96–105; p=.028) and diastolic BP of 84 mmHg (95% CI: 80–88; p=.029) post-treatment. Of the 54 cases in the magnesium group, 32 were normotensive post-treatment compared to only six from the morphine group (n=17). Conclusion There has been considerable difference of opinion as to the utility of magnesium in IS and a marked difference in the results of case series versus a small randomised control trial. This study suggests that the combination of morphine and magnesium is more effective in treating patients with IS than morphine alone.