الفهرس 
Introduction.Only 14 pages are availabe for public view
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Abstract
Hypomagnesemia is a common condition occurring in up to 60 to 65% of patients in intensive care units. Clinical manifestations of hypomagnesemia include generalized weakness, anorexia, Apathy, delirium, coma and generalized convulsions. Hypokalemia is frequently observed in hypomagnesemic patients as there is increased loss of potassium from the kidney in hypomagnesemic state. Hypocalcaemia is a sign of severe hypomagnesemia due to both inhibition of parathyroid hormone (PTH) secretion and bone resistance to its action.
Possible mechanisms of magnesium in preventing cardiac arrhythmias are stabilization of electrolyte concentrations in the heart muscle cell and membranes, calcium antagonism and decreasing neurotransmitter release e.g., adrenaline and noradrenaline. Magnesium depletion increases susceptibility to the arrhythmogenic effect of some drugs such as cardiac glycosides. The spectrum includes supraventricular and ventricular arrhythmias. Magnesium has a well-established role in management of Torsade de pointes, a repetitive polymorphic ventricular tachycardia with prolongation of QT intervals. In the recent guidelines of the American Heart Association and the American College of Cardiology for prevention and treatment of torsade de pointes, administration of magnesium and potassium is advice.
Hypomagnesemia can lead to hypertension by increasing intracellular calcium content secondary to decreased activation of calcium channels. Low Mg2+ levels can also cause both bronchoconstriction and vasoconstriction, resulting in more asthmatic exacerbations. Magnesium deficiency also may give rise to alterations in glucose metabolism Magnesium affects glucose homeostasis by influencing insulin secretion as well as glucose uptake by the cells. In addition; Low serum Mg levels have been implicated in the development of systemic inflammatory response syndrome (SIRS) and organ dysfunction.
Our aim in this study was to detect prevalence of hypomagnesemia in critically ill children, identify associated medical conditions and/or electrolyte abnormalities and to correlate this with organ dysfunction and mortality.
To achieve this target, we studied a series of 100 critically ill pediatric patients admitted to our pediatric intensive care unit of the Menoufia University Hospital from April 2015 to April 2016. All children incorporated in the study were subjected to: Careful history taking, thorough clinical examination and Laboratory investigations. PRISM score was calculated within 24hrs of admission for each patient, using the 14th measured clinical and laboratory variables. Data were entered on the website:http://www.sfar.org/scores2/prism2.php which calculated the PRISM score. Then we assessed the outcome of the patients as regard length of stay (LOS) and survival to discharge. Patients included in the study were divided into two groups based on serum magnesium level. Patients with serum magnesium < 1.5 mg/dl were considered hypomagnesemic (cases) and patients with serum magnesium >1.5 mg/dl and less than 2.3 mg/dl were considered normomagnesemic (controls).
Results:
On admission, 59% (59/100) of patients had hypomagnesemia and 41% (41/100) had normal serum magnesium level. Hypomagnesemia was associated with prolonged PICU stay, higher PRISM score, more frequent need for ventilator support, more frequent association with electrolyte abnormalities especially hypocalcemia and hypokalemia. There was also higher incidence of mortality, hypoalbuminemia, sepsis and elevated CRP levels in the hypomagnesemic group more than the normomagnesemic one. Performance of Mg+2 relative to sepsis was tested through ROC curve analysis; CRP was found to be the most superior as it achieved an AUC of 0.948 while Mg had an AUC of .638. The best magnesium cutoff point for prediction of sepsis in our study was 1.35 mg/dl with sensitivity of 69 % and specificity of 56%.Further analysis by ROC curve was performed to test the predictive power of Mg+2 along with other relevant factors for mortality. Mg+2 achieved an AUC of 0.576 (p = 0.049). Best Cut-off level for prediction of mortality in our study was 1.25 mg/dl with sensitivity of 61% and specificity of 71%. On the other hand, CRP and PRISM score can highly predict mortality with values of (AUC= 0.716, p = <0.001) and (AUC= 0. .811, p = <0.001) respectively.
Logistic regression analysis showed that that hypomagnesemia was a significant predictor for patients’ mortality (p value = 0.028). Patients with hypomagnesemia were 3.18 times more at risk of mortality than patients with normal magnesium level; OR 3.180 (0.854-7.965).
Conclusion
Hypomagnesemia was found to be associated with longer duration of stay in the pediatric intensive care unit, higher need for mechanical ventilation, higher PRISM score and higher incidence of mortality. Hypomagnesemia had statistically significant association with: hypocalcemia, hypokalemia, hypoalbuminemia and septicemia. As hypomagnesemia is responsible for increased morbidity and mortality, physicians should maintain a high index of suspicion for its early diagnosis and treatment.