Magnesium deficiency in critical illness

Effect of Magnesium on Ventricular Extrasystoles in Children

Magnesium (Mg) is a crucial element for cardiovascular system and its deficiency results in a variety of cardiac arrhythmias. The aim of this study is to determine the effect of oral Mg supplementation on the frequency of ventricular extrasystoles (VES) in children. Magnesium supplementation was given to 42 children who had VES without structural heart disease. Clinical, electrocardiographic, and Holter monitoring studies were reviewed. The mean baseline 24 h VES burden on Holter monitoring was 10.26% ± 4.13% and it was decreased to 6.62% ± 3.88% after. There was no significant difference between the pre-treatment serum Mg levels and the decrease in the frequency of VES. In conclusion, oral Mg therapy was found to be effective at suppressing VES in children regardless of serum Mg levels. Large and randomized studies are needed to demonstrate the effect of magnesium on VES suppression.

The Association between Magnesium Depletion Score and Hypertension in US Adults: Evidence from the National Health and Nutrition Examination Survey (2007-2018)

The magnesium depletion score (MDS) emerges as a new valuable predictor of the body's magnesium status index. This study aims to explore the link between MDS and hypertension (HTN) using the National Health and Nutrition Examination Survey (NHANES) data. A total of 9708 participants from NHANES (2007-2018) were enrolled to investigate MDS's connection with HTN. HTN was defined based on clinical guidelines. MDS classification (low, 0-1; middle, 2; high, 3-5) relied on alcohol consumption, diuretic use, proton-pump inhibitor (PPI) usage, and kidney disease. Multivariable logistic regression assessed MDS-HTN association. Subsequent analyses included interaction tests, subgroups, and sensitivity analysis. Each unit increase in MDS correlated with an 87% higher HTN risk (OR, 1.87; 95% CI, 1.64-2.13) after adjusting for confounders. High MDS participants exhibited significantly elevated HTN risk compared to low MDS counterparts (OR, 8.31; 95% CI, 4.81-14.36), with a significant trend across MDS groups (p < 0.001). Subgroup analyses supported a consistent positive correlation. Sensitivity analysis confirmed a robust association. The results indicated a positive correlation between MDS and the risk of developing HTN in US adults.

Unraveling the Puzzle: A Case of Intricate Neurological Presentation Attributable to Hypomagnesemia

Hypomagnesemia can occasionally present with severe neurological deficiencies, and it is usually attributed to an underlying renal and/or gastrointestinal pathology. Rarely, patients may present with neurological symptoms in the absence of an obvious cause. Our case highlights the importance of considering hypomagnesemia as a primary cause of those presenting with severe neurological deficits in an intensive care unit setting, as well as the significance of conducting a thorough social and medical history on these patients to elucidate their underlying causes. We discuss the case of a 48-year-old Caucasian male who acutely presented with seizures, tremors, visual hallucinations, diplopia, personality changes, and ataxia with recurring severely low magnesium (0.4 mg/dL) at times in the absence of renal, gastrointestinal, hormonal, infectious, or autoimmune pathology.

ESPEN practical guideline on clinical nutrition in hospitalized patients with acute or chronic kidney disease

BACKGROUND AND AIMS

Hospitalized patients often have acute kidney disease (AKD) or chronic kidney disease (CKD), with important metabolic and nutritional consequences. Moreover, in case kidney replacement therapy (KRT) is started, the possible impact on nutritional requirements cannot be neglected. On this regard, the present guideline aims to provide evidence-based recommendations for clinical nutrition in hospitalized patients with KD.

METHODS

The standard operating procedure for ESPEN guidelines was used. Clinical questions were defined in both the PICO format, and organized in subtopics when needed, and in non-PICO questions for the more general topics. The literature search was from January 1st, 1999 until January 1st, 2020. Each question led to one or more recommendation/statement and related commentaries. Existing evidence was graded, as well as recommendations and statements were developed and agreed upon in a multistage consensus process.

RESULTS

The present guideline provides 32 evidence-based recommendations and 8 statements, defining how to assess nutritional status, how to define patients at risk, how to choose the route of feeding, and how to integrate nutrition with KRT. In the final online voting, a strong consensus was reached in 84% at least of recommendations and 100% of statements.

CONCLUSION

The presence of KD in hospitalized patients identifies a highly heterogeneous group of subjects with widely varying nutrient needs and intakes. Considering the high nutritional risk related with this clinical condition, an individualized approach consisting of nutritional status evaluation and monitoring, frequent evaluation of nutritional requirements, and careful integration with KRT should be planned to avoid both underfeeding and overfeeding. Practical recommendations and statements were developed, aiming at defining suggestions for everyday clinical practice in the individualization of nutritional support in this patient setting. Literature areas with scarce or without evidence were also identified, thus requiring further basic or clinical research.

The Use of a Checklist to Optimize Electrolyte Replacement in the ICU

Electrolyte replacement protocols are routinely used in intensive care units (ICU) to guide magnesium replacement. Guided by serum levels, these protocols include no patient-specific factors despite a literature showing ICU patients routinely have significant deficits despite normal serum levels. The authors developed a checklist to help identify patients requiring more aggressive magnesium replacement than the electrolyte replacement protocol would provide. The checklist included risk factors for having significant magnesium deficits and for developing arrhythmias. The checklist was retrospectively applied to 364 medical ICU patients. Diabetic patients prescribed outpatient diuretics were defined as the highest-risk population. A total of 88% of patients in this subgroup had normal magnesium levels. Despite averaging 3.4 risk factors per patient, only 3 of 32 patients received magnesium. Applying the checklist would have suggested additional repletion for at least 85% of patients. A checklist can help identify ICU patients who may require more aggressive magnesium supplementation than protocols will provide.

Thinking Outside the Box: A Case of Persistent Symptomatic Hypomagnesemia

Although present in a significant number of people, hypomagnesemia is still an undervalued diagnosis. Therefore, its awareness and comprehensive etiological investigation become imperative. Among its multiple possible causes, drug iatrogenesis plays an important and often overlooked role. Here, we present a case of a 78-year-old female with recurrent bouts of severe hypomagnesemia of unknown origin, which, after an extensive study, was determined to be induced by proton pump inhibitors (PPIs). As such, our goal is to raise awareness of the potential risk of this side effect even in monotherapy, as well as to elucidate its underlying mechanisms, which are still not fully understood. Furthermore, it is intended to foster a systematic therapeutic review in these patients and raise discussion about the potential benefits of systematic magnesium monitoring in patients on long-term PPIs.

Ionized Magnesium Correlates With Total Blood Magnesium in Pediatric Patients Following Kidney Transplant

Background

Abnormal serum magnesium (Mg) concentrations are common and associated with worse mortality in kidney-transplant recipients. Many kidney and transplant-related factors affect Mg homeostasis. The concentration of the active form, ionized Mg (iMg), is not measured clinically, and total Mg (tMg) and iMg correlations have conflicted. We hypothesized that iMg and tMg concentrations show poor categorical agreement (i.e., low, normal, and high) in kidney-transplant recipients but that ionized calcium (iCa) correlates with iMg.

Methods

We retrospectively evaluated hypomagnesemia in kidney-transplant recipients over a 2-yr period. We prospectively collected blood at 0-28 days post-transplant to measure correlations between iMg and iCa/tMg. iMg and iCa concentrations in the reference ranges of 0.44-0.65 and 1.0-1.3 mmol/L, respectively, were considered normal. Fisher's exact test and unweighted kappa statistics revealed category agreements. Pearson's correlation coefficients and linear regression measured correlations.

Results

Among 58 retrospective kidney-transplant recipients, 54 (93%) had tMg<0.66 mmol/L, 28/58 (48%) received Mg supplementation, and 20/28 (71%) had tacrolimus dose adjustments during supplementation. In 13 prospective transplant recipients (N=43 samples), iMg and tMg showed strong category agreement (P=0.0003) and correlation (r=0.71, P<0.001), whereas iMg and iCa did not (P=0.7; r=-0.25, P=0.103, respectively).

Conclusions

tMg and iMg exhibited strong correlation following kidney transplantation. However, iCa may not be an accurate surrogate for iMg. Determining the effect of Mg supplementation and the Mg concentration where supplementation is clinically necessary are important next steps.

Magnesium (Mg2+): Essential Mineral for Neuronal Health: From Cellular Biochemistry to Cognitive Health and Behavior Regulation

Magnesium (Mg2+) is a crucial mineral involved in numerous cellular processes critical for neuronal health and function. This review explores the multifaceted roles of Mg2+, from its biochemical interactions at the cellular level to its impact on cognitive health and behavioral regulation. Mg2+ acts as a cofactor for over 300 enzymatic reactions, including those involved in ATP synthesis, nucleic acid stability, and neurotransmitter release. It regulates ion channels, modulates synaptic plasticity, and maintains the structural integrity of cell membranes, which are essential for proper neuronal signaling and synaptic transmission. Recent studies have highlighted the significance of Mg2+ in neuroprotection, showing its ability to attenuate oxidative stress, reduce inflammation, and mitigate excitotoxicity, thereby safeguarding neuronal health. Furthermore, Mg2+ deficiency has been linked to a range of neuropsychiatric disorders, including depression, anxiety, and cognitive decline. Supplementation with Mg2+, particularly in the form of bioavailable compounds such as Magnesium-L-Threonate (MgLT), Magnesium-Acetyl-Taurate (MgAT), and other Magnesium salts, has shown some promising results in enhancing synaptic density, improving memory function, and alleviating symptoms of mental health disorders. This review highlights significant current findings on the cellular mechanisms by which Mg2+ exerts its neuroprotective effects and evaluates clinical and preclinical evidence supporting its therapeutic potential. By elucidating the comprehensive role of Mg2+ in neuronal health, this review aims to underscore the importance of maintaining optimal Mg2+ levels for cognitive function and behavioral regulation, advocating for further research into Mg2+ supplementation as a viable intervention for neuropsychiatric and neurodegenerative conditions.

A systematic review for prevention of cisplatin-induced nephrotoxicity using different hydration protocols and meta-analysis for magnesium hydrate supplementation

BACKGROUND

Nephrotoxicity remains the most serious side effect of cisplatin therapy. Cisplatin-induced nephrotoxicity (CIN) limits the use of this drug and affects up to 20% of patients. Several possible interventions such as magnesium supplementation may prevent CIN. This study aimed to review different types of hydration protocols and we conducted a meta-analysis of magnesium supplementation to understand its effect in protecting against CIN.

METHODS

A search of the PubMed, Embase, and Cochrane databases was performed. Trials were eligible if they enrolled patients who received cisplatin and different hydration protocols to prevent CIN. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the efficacy of different protocols.

RESULTS

We initially identified 1113 different studies and included 33 of them which met the selection criteria. A meta-analysis of 11 retrospective studies that examined magnesium supplementation during hydration showed that this treatment provided significant protection against CIN (OR = 0.22, 95% CI = 0.14 to 0.35).

CONCLUSION

There has been uncertainty regarding the best method to prevent CIN. Our results highlight the potentially protective effect of magnesium supplementation during hydration. This study is registered in PROSPERO, CRD42020212682.

Osmotic Demyelination Syndrome in a Normonatremic Patient Under Treatment With Proton Pump Inhibitors

A 66-year-old woman was admitted to the emergency department with diarrhea, nausea, and vomiting as well as low-grade fever. She was initially treated with ciprofloxacin and metronidazole with symptomatic improvement and was discharged. One week later, she returned to the emergency department for gait instability, dizziness, and vomiting and had a witnessed generalized tonic-clonic seizure in the hospital. During both admissions, the presence of ionic alterations such as severe hypomagnesemia, hypophosphatemia, and hypokalemia stood out, while sodium levels remained normal. Among her antecedents, she had a hiatal hernia and had been receiving treatment with omeprazole for years.

The Role of Platelet-Activating Factor and Magnesium in Obstetrics and Gynecology: Is There Crosstalk between Pre-Eclampsia, Clinical Hypertension, and HELLP Syndrome?

Clinical hypertension is a complex disease of the cardiovascular system that can affect the body's ability to physiologically maintain homeostasis. Blood pressure is measured as systolic pressure of the heart and diastolic pressure. When the systolic pressure exceeds values of 130-139 and diastolic exceeds 80-89, the body is in stage 1 hypertension. A pregnant woman with hypertension is predisposed to developing pre-eclampsia during gestation between the 1st and 2nd trimester. If the symptoms and changes in the mother's body are not controlled, this can progress to hemolysis, elevated liver enzymes, and low platelet count also known as HELLP syndrome. The onset of HELLP syndrome generally begins before the 37th week of pregnancy. Magnesium is one of the most used cations in clinical medicine with various implications in the body. With a critical role in vascular smooth muscle, endothelium, and myocardial excitability it is used in treatment of clinical hypertension, pre-eclampsia in gestational periods, and HELLP syndrome. Platelet-activating factor (PAF) is an endogenous phospholipid proinflammatory mediator that is released in response to various biological and environmental stressors. When released it causes platelets to aggregate, further exacerbating hypertension. The purpose of this literature review is to investigate the role that magnesium and platelet-activating factors have on clinical hypertension, pre-eclampsia, and HELLP syndrome while focusing on the interplay between these molecules.

Management for Electrolytes Disturbances during Continuous Renal Replacement Therapy

Despite the lack of proven superiority in mortality compared to intermittent hemodialysis, continuous renal replacement therapy (CRRT) is the preferred renal replacement therapy modality for critically ill patients with acute kidney injury (AKI) due to better hemodynamic stability and steady correction of electrolytes disturbances and volume overload. Multiple and complex electrolyte disorders in patients with AKI can be managed effectively with CRRT because controlled and predictable correction is feasible. Thus, CRRT has an advantage with safety over conventional hemodialysis, especially in patients with both renal dysfunction and electrolyte disorder that require a sophisticated treatment with avoidance of rapid correction. On the contrary, CRRT can potentially lead to paradoxical disturbance of electrolytes such as hypokalemia or hypophosphatemia, especially in patients under high dose or prolonged duration of CRRT treatment. These electrolytes related complications can be prevented with close monitoring followed by the appropriate use of CRRT fluids. Although there is a lack of solid evidence and standardized guideline for CRRT prescriptions, optimal management of various electrolyte disturbances can be achieved with individualized and tailored dialysate and replacement fluid prescriptions. Several commercially available CRRT solutions with varying compositions provide flexibility to manage electrolyte disorders and maintain the stability of electrolyte. In this review, we discuss various prescription methods to manage common electrolyte imbalances as well as preventative strategies to maintain electrolyte homeostasis during CRRT providing detailed protocols used in our center. This review may contribute to future research that can lead to the development of clinical practice guidelines.

Magnesium Depletion Score is Associated with Long-Term Mortality in Chronic Kidney Diseases: A Prospective Population-Based Cohort Study

BACKGROUND

Magnesium deficiency is common in patients with chronic kidney diseases (CKD) due to restricted magnesium intake and impaired magnesium reabsorption. Based on pathophysiological risk factors influencing kidney magnesium reabsorption, a magnesium depletion score (MDS) was developed. Using MDS as a novel indicator for assessing body magnesium status, we hypothesized that it was associated with clinical prognosis.

METHODS

We conducted a prospective population-based cohort study using data from the National Health and Nutrition Examination Survey 1999-2014 to explore the impact of MDS on the clinical outcomes of CKD patients. Propensity score-matched analyses were conducted to increase comparability. The primary outcome was all-cause mortality, and the secondary outcomes were cardiovascular-cause and cancer-cause mortality.

RESULTS

After propensity score matching, 3294 CKD patients were divided into 2 groups: MDS ≤ 2 (N = 1647), and MDS > 2 (N = 1647). During a median follow-up of 75 months, Kaplan-Meier analyses showed that MDS > 2 was associated with worse 5- and 10-year overall survival (78.5% vs 73.4%; 53.1% vs 43.1%, P < 0.001). After adjusting for confounding variables, MDS was found to be an independent risk factor for all-cause mortality (HR:1.34, 95% CI 1.20-1.50, P < 0.001). MDS > 2 was also associated with higher cardiovascular-cause mortality (16.2% VS 11.6%, P = 0.005). Multivariate competing risk analysis revealed that MDS > 2 was an independent risk factor (HR: 1.33, 95% CI 1.06-1.66, P = 0.012). Subgroup analyses reported that MDS > 2 increased all-cause mortality and cardiovascular-cause mortality only in patients with inadequate magnesium intake (P < 0.001, P < 0.001) but not in those with adequate intake (P = 0.068, P = 0.920).

CONCLUSIONS

A magnesium depletion score > 2 was independently associated with higher long-term cardiovascular-cause and all-cause mortality in CKD patients.

Association of Serum Magnesium and Risk of Morbidity and Mortality in ICU-Admitted Patients Based on COVID-19 Infection Classification

Background: Magnesium (Mg) deficiency is a common clinical electrolyte abnormality in critically ill patients, which is related to higher mortality and is easily ignored. Objectives: We aimed to investigate the association of Mg levels with mortality and comorbidity in patients admitted to the intensive care unit (ICU) based on COVID-19 infection classification. Methods: A total of 69 patients admitted to the ICU of Shahid Mohammadi Hospital, Bandar Abbas, Iran, from June to December 2021were included in the present study. The serum Mg was measured in these patients. Data from sequential organ failure assessment (SOFA), acute physiologic assessment and chronic health evaluation (APACHE), ICU stay length, mechanical ventilation duration, mortality, and comorbidity were determined. Moreover, the COVID-19 infection was detected by PCR. Results: The mean ± SD age of patients (34.8% male) was 52.56 ± 16.43 years. Out of 69 patients, 18 (26.1%) died during hospitalization, and 24 (34.8%) required mechanical ventilation. The prevalence of COVID-19 was 39.1% (27 patients). Our results showed no difference in serum Mg between patients based on mortality and comorbidity status. However, the Mg level of patients with kidney failure was significantly higher than patients without kidney failure (P < 0.05). Based on the COVID-19 classification, there was only a positive correlation between hypomagnesemia and the length of ICU hospitalization in patients without COVID-19 (P < 0.05). Conclusions: Our findings showed no difference in the Mg levels of patients based on mortality status. Patients with kidney failure had higher serum Mg than those without kidney failure. Furthermore, our results showed no difference in the Mg levels of critically ill patients based on COVID-19 infection status.

Hypocalcemia in hospitalized patients with COVID-19: roles of hypovitaminosis D and functional hypoparathyroidism

INTRODUCTION

Despite the high prevalence of hypocalcemia in patients with COVID-19, very limited studies have been designed to evaluate etiologies of this disorder. This study was designed to evaluate the status of serum parameters involved in calcium metabolism in patients with COVID-19 and hypocalcemia.

MATERIALS AND METHODS

This cross-sectional study was conducted on 123 hospitalized patients with COVID-19. Serum concentrations of PTH, 25 (OH) D, magnesium, phosphate, and albumin were assessed and compared across three groups of moderate/severe hypocalcemia (serum total calcium < 8 mg/dl), mild hypocalcemia (8 mg/dl ≤ serum total calcium < 8.5 mg/dl) and normocalcemia (serum total calcium ≥ 8.5 mg/dl). Multivariate analyses were performed to evaluate the independent roles of serum parameters in hypocalcemia.

RESULTS

In total, 65.9% of the patients had hypocalcemia. Vitamin D deficiency was found in 44.4% and 37.7% of moderate/severe and mild hypocalcemia cases, respectively, compared to 7.1% in the normal serum total calcium group (P = 0.003). In multivariate analysis, vitamin D deficiency was independently associated with 6.2 times higher risk of hypocalcemia (P = 0.001). Only a minority of patients with hypocalcemia had appropriately high PTH (15.1% and 14.3% in mild and moderate/severe hypocalcemia, respectively). Serum PTH was low/low-normal in 40.0% of patients with moderate/severe low-corrected calcium group. Magnesium deficiency was not associated with hypocalcemia in univariate and multivariate analysis.

CONCLUSION

Vitamin D deficiency plays a major role in hypocalcemia among hospitalized patients with COVID-19. Inappropriately low/low-normal serum PTH may be a contributing factor in this disorder.

Intravenous magnesium sulfate inducing acute respiratory failure in a patient with myasthenia gravis

A woman in her 90s with a background of myasthenia gravis and atrial fibrillation presented to hospital following a fall. While in the emergency department it was noted that she was in atrial fibrillation with a fast-ventricular response and as part of her management was given intravenous magnesium. Following this she developed acute respiratory failure and required intubation and ventilation. The patient recovered quickly and was extubated in the intensive care unit the next day. On subsequent days, the patient received two further doses of intravenous magnesium before the link was identified. On both of these occasions she again developed respiratory failure which were managed with non-invasive ventilation. This case highlights the importance of all members of the team being aware of the drugs that can induce a myasthenic crisis. It also stimulates further research into the development of a guide of how to safely treat symptomatic hypomagnesaemia in patients with myasthenia gravis.

Genome-Wide Analyses of Nephrotoxicity in Platinum-Treated Cancer Patients Identify Association with Genetic Variant in RBMS3 and Acute Kidney Injury

Nephrotoxicity is a common and dose-limiting side effect of platinum compounds, which often manifests as acute kidney injury or hypomagnesemia. This study aimed to investigate the genetic risk loci for platinum-induced nephrotoxicity. Platinum-treated brain tumor and head–neck tumor patients were genotyped with genome-wide coverage. The data regarding the patient and treatment characteristics and the laboratory results reflecting the nephrotoxicity during and after the platinum treatment were collected from the medical records. Linear and logistic regression analyses were performed to investigate the associations between the genetic variants and the acute kidney injury and hypomagnesemia phenotypes. A cohort of 195 platinum-treated patients was included, and 9,799,032 DNA variants passed the quality control. An association was identified between RBMS3 rs10663797 and acute kidney injury (coefficient −0.10 (95% confidence interval −0.13–−0.06), p-value 2.72 × 10⁻⁸). The patients who carried an AC deletion at this locus had statistically significantly lower glomerular filtration rates after platinum treatment. Previously reported associations, such as BACH2 rs4388268, could not be replicated in this study’s cohort. No statistically significant associations were identified for platinum-induced hypomagnesemia. The genetic variant in RBMS3 was not previously linked to nephrotoxicity or related traits. The validation of this study’s results in independent cohorts is needed to confirm this novel association.

Hypermagnesaemia, but Not Hypomagnesaemia, Is a Predictor of Inpatient Mortality in Critically Ill Children with Sepsis

Objective

The effect of serum magnesium on the prognosis of children with sepsis in the pediatric intensive care unit (PICU) is unclear. This study was designed to assess the risk of inpatient mortality for children with sepsis in the PICU based on serum magnesium levels at admission.

Methods

We collected patients' clinical information from the Pediatric Intensive Care database and then performed locally weighted scatterplot smoothing (LOWESS) analysis, Kaplan–Meier analysis, and multivariate logistic regression to determine the relationship between admission serum magnesium and inpatient mortality in children with sepsis.

Results

A total of 974 critically ill children with sepsis were included, with 246 patients in the hypomagnesemia group, 666 in the normal group, and 62 in the hypermagnesemia group. The chi-square test suggested that the hypermagnesemia group had higher in-hospital mortality than the normal group (14.5% vs. 2.4%, P < 0.001). Kaplan–Meier curves revealed that the 30-day overall survival rate was lower in the hypermagnesaemia group than in the normal group (P < 0.001). The multivariate logistic regression model revealed that hypermagnesaemia was a risk factor related to inpatient mortality (odds ratio 4.22, 95% CI 1.55-11.50), while hypomagnesaemia was not a significant factor for inpatient mortality (odds ratio 0.78, 95% CI 0.26-2.32).

Conclusion

Hypermagnesaemia, but not hypomagnesaemia, is a predictor of inpatient mortality in critically ill children with sepsis.

Preventive effect of 20 mEq and 8 mEq magnesium supplementation on cisplatin-induced nephrotoxicity: a propensity score-matched analysis

PURPOSE

The protective effect of magnesium (Mg) supplementation against cisplatin (CDDP)-induced nephrotoxicity has been widely described; however, the optimal dose of Mg supplementation is unclear. The aim of this study was to investigate whether 20 mEq of Mg supplementation is more effective than 8 mEq Mg in preventing CDDP-induced nephrotoxicity, as well as the associated risk factors, in cancer patients treated with CDDP-based chemotherapy.

METHODS

Pooled data of 272 patients receiving 20 mEq or 8 mEq Mg supplementation to CDDP-based chemotherapy from a multicenter, retrospective, observational study were compared using propensity score matching. Separate multivariate logistic regression analyses were used to identify the risk factors for renal failure induced by each treatment dose.

RESULTS

There was no significant difference in the incidence of nephrotoxicity between the 8 mEq and 20 mEq groups (P = 0.926). There was also no significant difference in the severity of nephrotoxicity, elevated serum creatinine levels, and decreased estimated creatinine clearance levels between the two groups. Cardiac disease and albumin levels were identified as independent risk factors for CDDP-induced nephrotoxicity.

CONCLUSION

We did not find an advantage of 20 mEq over 8 mEq Mg supplementation in terms of a preventive effect against CDDP-induced nephrotoxicity. The optimal dose of Mg supplementation for the prevention of CDDP-induced nephrotoxicity remains unknown, and further studies are warranted.

A prospective observational study to identify the effectiveness of intravenous magnesium replacement in an intensive care setting

Background and Aims

To estimate the incidence of hypomagnesemia and identify the effectiveness of a calculated dose of intravenous magnesium sulfate (MgSO₄) in correction of hypomagnesemia and its relationship with renal function in critically ill patients.

Material and Methods

All patients admitted in the adult intensive care unit were enrolled in the study and magnesium levels were monitored. Patients with serum magnesium levels <1.7 mg/dL received calculated doses of Intravenous MgSO₄. The average rise in serum magnesium levels per gram of MgSO₄ administered was calculated and relationship with estimated glomerular filtration rate (eGFR) was identified.

Results

In total, 27.27% of patients admitted in our intensive care unit had an incidence of hypomagnesemia. The average rise of serum magnesium levels in patients with hypomagnesemia was 0.13 (±0.05) mg/dl. The average rise of serum magnesium levels was 0.10 (±0.04) mg/dL in patients with eGFR ≥ 90 mL/min/1.73 m² and 0.15 (± 0.05) mg/dL in patients with eGFR < 90 mL/min/1.73 m². This difference between the two groups (P-value = 0.002) and the trend of increasing average rise in serum magnesium levels with declining eGFR values (P-value = 0.013) were both statistically significant.

Conclusion

Incidence of hypomagnesemia in the critically ill population is around 27.27%. Intravenous administration of 1 g of MgSO₄ results in a rise of serum magnesium levels by 0.1 mg/dL in patients with normal eGFR and around 0.15 mg/dL in patients with eGFR values between 30 and 89 mL/min/1.73 m².

Anxiolytic effect of chronic intake of supplemental magnesium chloride in rat

Evidence suggest that magnesium dietary supplementation has several health benefits including lowering blood pressure, reducing insulin resistance, and improving symptoms of depression, anxiety, and migraine. Here, we aimed to study the effect of chronic magnesium supplementation on anxiety-like behavior in rats by supplementing with magnesium their drinking water for 30 days. Anxiety-like behavior was induced by subcutaneous injection of veratrin 30 min before performing elevated plus maze and open field tests to measure anxiety levels and locomotion, respectively. We quantify the concentration of magnesium in plasma and cerebrospinal fluid. We used diazepam to compare the efficacy of magnesium supplementation as an anxiolytic agent. Our results show that rats supplemented with magnesium had a statistically significant decrease in anxiety levels with not effects on locomotion and a statistically significant increase in concentration of magnesium in plasma and cerebrospinal fluid. However, the anxiolytic effect of magnesium supplementation washes-out in 12 days. We discuss the advantages of using supplemental magnesium as anxiolytic.

Magnesium Depletion Score (MDS) Predicts Risk of Systemic Inflammation and Cardiovascular Mortality among US Adults

BACKGROUND

Kidney reabsorption of magnesium (Mg) is essential for homeostasis.

OBJECTIVES

We developed and validated models with the kidney reabsorption-related magnesium depletion score (MDS) to predict states of magnesium deficiency and disease outcomes.

METHODS

MDS was validated in predicting body magnesium status among 77 adults (aged 62 ± 8 y, 51% men) at high risk of magnesium deficiency in the Personalized Prevention of Colorectal Cancer Trial (PPCCT) (registered at clinicaltrials.gov as NCT01105169) using the magnesium tolerance test (MTT). We then validated MDS for risk stratification and for associations with inflammation and mortality among >10,000 US adults (weighted: aged 48 ± 0.3 y, 47% men) in the NHANES, a nationally representative study. A proportional hazards regression model was used for associations between magnesium intake and the MDS with risks of total and cardiovascular disease (CVD) mortality.

RESULTS

In the PPCCT, the area under the receiver operating characteristic (ROC) curve (AUC) for magnesium deficiency was 0.63 (95% CI: 0.50, 0.76) for the model incorporating the MDS with sex and age compared with 0.53 (95% CI: 0.40, 0.67) for the model with serum magnesium alone. In the NHANES, mean serum C-reactive protein significantly increased with increasing MDS (P-trend < 0.01) after adjusting for age and sex and other covariates, primarily among individuals with magnesium intake less than the Estimated Average Requirement (EAR; P-trend < 0.05). Further, we found that low magnesium intake was longitudinally associated with increased risks of total and CVD mortality only among those with magnesium deficiency predicted by MDS. MDS was associated with increased risks of total and CVD mortality in a dose-response manner only among those with magnesium intake less than the EAR.

CONCLUSIONS

The MDS serves as a promising measure in identifying individuals with magnesium deficiency who may benefit from increased intake of magnesium to reduce risks of systemic inflammation and CVD mortality. This lays a foundation for precision-based nutritional interventions.

Ca:Mg Ratio, APOE Cytosine Modifications, and Cognitive Function: Results from a Randomized Trial

BACKGROUND

Deterioration of ionized calcium (Ca2+) handling in neurons could lead to neurodegenerative disease. Magnesium (Mg) antagonizes Ca during many physiologic activities, including energy metabolism and catalyzation of demethylation from 5-methylcytosine(5-mC) to 5-hydroxymethylcytosine(5-hmC).

OBJECTIVE

To test the hypothesis that actively reducing the Ca:Mg intake ratio in the diet through Mg supplementation improves cognitive function, and to test whether this effect is partially mediated by modified cytosines in Apolipoprotein E (APOE).

METHODS

This study is nested within the Personalized Prevention of Colorectal Cancer Trial (PPCCT), a double-blind 2×2 factorial randomized controlled trial, which enrolled 250 participants from Vanderbilt University Medical Center. Target doses for both Mg and placebo arms were personalized.

RESULTS

Among those aged > 65 years old who consumed a high Ca:Mg ratio diet, we found that reducing the Ca:Mg ratio to around 2.3 by personalized Mg supplementation significantly improved cognitive function by 9.1% (p = 0.03). We also found that reducing the Ca:Mg ratio significantly reduced 5-mC at the cg13496662 and cg06750524 sites only among those aged > 65 years old (p values = 0.02 and 0.03, respectively). Furthermore, the beneficial effect of reducing the Ca:Mg ratio on cognitive function in those aged over 65 years was partially mediated by reductions in 5-mC levels (i.e., cg13496662 and cg06750524) in APOE (p for indirect effect = 0.05).

CONCLUSION

Our findings suggest that, among those age 65 and over with a high dietary Ca:Mg ratio, optimal Mg status may improve cognitive function partially through modifications in APOE methylation. These findings, if confirmed, have significant implications for the prevention of cognitive aging and Alzheimer's disease.Clinical Trial Registry number and website: #100106 https://clinicaltrials.gov/ct2/show/NCT03265483.

Blunted PTH response to vitamin D insufficiency/deficiency and colorectal neoplasia risk

BACKGROUND & AIMS

In contrast to many observational studies, large-scale randomized trials do not support the protective role of vitamin D for the prevention of colorectal neoplasia. However, in previous studies, individuals with blunted parathyroid hormone (PTH) response to vitamin D insufficiency/deficiency (BPRVID), were not differentiated from those with high PTH response to vitamin D insufficiency/deficiency (HPRVID). Individuals with BPRVID are responsive to magnesium treatment, particularly treatment of magnesium plus vitamin D while those with HPRVID are responsive to vitamin D treatment. We prospectively compared these two distinct groups (i.e. BPRVID and HPRVID) for risk of incident adenoma, metachronous adenoma, and incident colorectal cancer (CRC) METHODS: Three nested case-control studies in the Prostate, Lung, Colorectal and Ovarian Cancer (PLCO) Screening Trial.

RESULTS

We found optimal 25(OH)D levels were associated with a significantly reduced risk of CRC, primarily among women. The associations between 25(OH)D and CRC risk significantly differed by PTH levels, particularly among women. Compared to individuals with optimal levels for both 25(OH)D and PTH, all others were at an elevated risk of incident CRC, primarily in women. We found those with BPRVID had 2.56-fold significantly increased risk of CRC compared to 1.65-fold non-significantly increased risk for those with HPRVID. Among women, we observed those with BPRVID had 4.79-6.25-fold significantly increased risks of incident CRC and adenoma whereas those with HPRVID had 3.65-fold significantly increased risk of CRC.

CONCLUSIONS

Individuals with BPRVID are at higher risks of incident adenoma and CRC compared to those with HPRVID, particularly among women.

Short-term recovery in patients suffering hypoparathyroid after thyroidectomy: a case control study

BACKGROUND

Postoperative hypoparathyroidism is the main reason for outpatient follow-up and long-term oral calcium and calcitriol treatment. Our study investigated the influencing factors and powerful predictors of short-term postoperative parathyroid function recovery.

METHODS

Logistic regression was used to compare the clinicopathological characteristics; surgical details; and serum calcium (Ca), magnesium (Mg), and phosphorus (P) concentrations of patients. A receiver operating characteristic (ROC) curve was used to analyze the predictors of normal parathyroid hormone (PTH).

RESULTS

Among the 111 patients with PTH < 10 pg/mL on the first postoperative day, most patients experienced a return to normal PTH (PTH > 15 pg/mL) within 30 days postoperatively. Univariate analysis showed that Pod (postoperative day) 1 PTH, Pod3 PTH, Pod7 Ca, Pod7 Mg, and Pod7 P (P < 0.05) were associated with parathyroid function recovery to normal on the seventh postoperative day. Multivariate logistic regression analysis revealed the following independent risk factors for normal PTH levels at Pod7 after thyroidectomy: Pod3 PTH (P = 0.038), Pod1 PTH (P = 0.056), Pod7 Mg (P = 0.001), Pod7 P (P = 0.020), and the number of parathyroid glands in situ intraoperatively. The combined sensitivity of serum magnesium concentration and phosphorus concentration to predict parathyroid function recover to normal on the seventh postoperative day was 82.76%, with a sensitivity of 76.83%.

CONCLUSION

Serum magnesium, phosphorus and PTH concentrations are important influencing factors and effective predictors of short-term postoperative parathyroid function recovery to normal. Serum ion is an effective auxiliary diagnostic method for hypoparathyroidism after thyroidectomy.

Stroke mimic in an acute rehabilitation unit patient with associated hypomagnesaemia

This case report describes a patient who presented with acute left facial numbness and eyelid weakness prompting work-up, which demonstrated low suspicion for new stroke but revealed hypomagnesaemia as a potential differential diagnosis. Patient initially presented to the emergency department with left upper extremity weakness and was diagnosed with right basal ganglia infarction. Two weeks after transfer to the acute rehabilitation unit, patient suddenly complained of left facial numbness and eyelid weakness. However, brain imaging did not show any new acute infarct. Instead, laboratory results showed hypomagnesaemia at 1.50 mg/dL. Patient was therefore treated with intravenous magnesium leading to resolution of his symptoms. Up to 30% of acute stroke presentations are stroke mimics. Although hypomagnesaemia is less frequently seen as a mimic, its neuromuscular manifestations may present with similar symptoms. Patients will always benefit from a comprehensive evaluation for stroke symptoms, but it is important to consider the mimics as well.

Effect of magnesium sulphate on the intracranial pressure of preeclampsia patients using ultrasound-guided optic nerve sheath diameter: A pilot study

Background:

Increased intracranial pressure (ICP) is a known complication of pre-eclampsia with severe features. The use of magnesium sulphate (MgSO₄) is the standard treatment and is associated with marked reduction of cerebral perfusion pressure (CPP) and prevention of cerebral damage. Optic nerve sheath diameter (ONSD) ultrasonography is a bedside tool used to reflect changes in the ICP. The aim of this study is to detect the effect of MgSO₄ administration on ICP in severe preeclampsia through measuring changes in the ONDS.

Methods:

Thirty pregnant female patients suffering from severe pre-eclampsia were enrolled in this prospective pilot study. Ultrasound measurement of ONSD was measured before the commencement of MgSO4 and after 1, 6, and 24 h after the administration.

Results:

There was a significant difference in ONSD measurements between that at baseline and post magnesium administration at 1, 6, and 24 h (P-value 0.001). Additionally, a significant difference in measurements between 1 and 6 and 6 and 24 h after magnesium initiation (P-value 0.001).

Conclusions:

Ultrasound ONSD measurement in patients with severe preeclampsia is a non-invasive easy tool to detect increased intracranial pressure and monitor the response to magnesium sulphate infusion.

ESPEN guideline on clinical nutrition in hospitalized patients with acute or chronic kidney disease

Acute kidney disease (AKD) - which includes acute kidney injury (AKI) - and chronic kidney disease (CKD) are highly prevalent among hospitalized patients, including those in nephrology and medicine wards, surgical wards, and intensive care units (ICU), and they have important metabolic and nutritional consequences. Moreover, in case kidney replacement therapy (KRT) is started, whatever is the modality used, the possible impact on nutritional profiles, substrate balance, and nutritional treatment processes cannot be neglected. The present guideline is aimed at providing evidence-based recommendations for clinical nutrition in hospitalized patients with AKD and CKD. Due to the significant heterogeneity of this patient population as well as the paucity of high-quality evidence data, the present guideline is to be intended as a basic framework of both evidence and - in most cases - expert opinions, aggregated in a structured consensus process, in order to update the two previous ESPEN Guidelines on Enteral (2006) and Parenteral (2009) Nutrition in Adult Renal Failure. Nutritional care for patients with stable CKD (i.e., controlled protein content diets/low protein diets with or without amino acid/ketoanalogue integration in outpatients up to CKD stages four and five), nutrition in kidney transplantation, and pediatric kidney disease will not be addressed in the present guideline.

Hypocalcemia secondary to hypomagnesemia in a patient on liraglutide

A 73-year-old man with type 2 diabetes on Liraglutide with a history of coronary artery disease. Admitted to emergency for abdominal pain, severe diarrhea and episodes of tetany attacks. Laboratory workup reveals hypomagnesemia, hypocalcemia and normal parathormone (PTH). After intravenous administration of magnesium and calcium, the blood ionogram quickly normalized. In addition, plasma levels of intact parathyroid hormone increased immediately after magnesium administration. Strongly suggests that hypocalcemia resulted from a disruption of adequate parathyroid hormone secretion caused by hypomagnesemia which in turn was caused by severe diarrhea under treatment with Liraglutide.

Water desalination, serum magnesium and dementia: a population-based study

Although dementia affects roughly 50 million people worldwide, its etiology is largely unknown. Recent studies have found a link between hypermagnesemia, hypomagnesemia, and increased risk of dementia. In this study, we explore the link between serum magnesium levels and the prevalence of dementia following the adoption of desalinated water (DSW) in Israel. DSW contains no magnesium, and relying on it for drinking water can lead to an increased incidence of hypomagnesia. Our objective was to analyze in a treat-control context how the switch to desalinated drinking water affected serum magnesium concentrations and the prevalence of dementia. We selected two cities which differed in terms of their access to underground aquifers but were otherwise similar. Rehovot has no underground water and uses over 90% DSW, whereas Kfar Saba relies almost entirely on its own aquifers. The cities are otherwise relatively similar in terms of their demographic composition. Using medical records for all subjects insured by the Maccabi Health Services in Rehovot (n = 23,991) and Kfar Saba (n = 20,541), we examined mean serum concentrations of Mg in the period prior to desalination (2001-2006) and post-desalination (2007-2018). Dementia prevalence is taken from 2007 to 2020 for the same coverage population. Serum magnesium levels were significantly lower in Rehovot following the switch to DSW (2.067 ± 0.21 pre-desalination and 2.059 ± 0.216 post-desalination, p < 0.01). In contrast, serum magnesium levels increased in Kfar Saba, which continued to rely on groundwater (2.008 ± 0.179 vs. 2.067 ± 0.206, p < 0.01). The prevalence of dementia was similar in the two cities (488/20,541, 2.37% in Rehovot and 613/23,991, 2.55% in Kfar Saba). In this ecological study, the adoption of DSW was associated with a significant decrease in serum magnesium concentrations. However, this change was not associated with a higher prevalence of dementia. While this association study cannot rule out some effect of hypomagnesemia on dementia morbidity, it suggests that the effect, if it exists, is relatively small.

Prevention of hypomagnesemia in critically ill patients with acute kidney injury on continuous kidney replacement therapy: the role of early supplementation and close monitoring

Hypomagnesemia is a common electrolyte disorder in critically ill patients and is associated with increased morbidity and mortality risk. Many clinical conditions may contribute to hypomagnesemia through different pathogenetic mechanisms. In patients with acute kidney injury (AKI) the need for continuous or prolonged intermittent kidney replacement therapy (CKRT and PIKRT, respectively) may further add to other causes of hypomagnesemia, especially when regional citrate anticoagulation (RCA) is used. The basic principle of RCA is chelation of ionized calcium by citrate within the extracorporeal circuit, thus blocking the coagulation cascade. Magnesium, a divalent cation, follows the same fate as calcium; the amount lost in the effluent includes both magnesium-citrate complexes and the free fraction directly diffusing through the hemofilter. While increasing the magnesium content of dialysis/replacement solutions may decrease the risk of hypomagnesemia, the optimal concentration for the variable combination of solutions adopted in different KRT protocols has not yet been identified. An alternative and effective approach is based on including early intravenous magnesium supplementation in the KRT protocol, and close monitoring of serum magnesium levels, especially in the setting of RCA. Thus, strategies aimed at precisely tailoring both dialysis prescriptions and the composition of KRT fluids, as well as early magnesium supplementation and close monitoring, could represent a cornerstone in reducing KRT-related hypomagnesemia.

Predictive Validity of a QTc Interval Prolongation Risk Score in the Intensive Care Unit

BACKGROUND

Torsade de pointes is a form of polymorphic ventricular tachycardia associated with heart rate-corrected QT (QT_c ) interval prolongation. With approximately 24-61% of critically ill patients experiencing QT_c interval prolongation, a predictive tool to identify high-risk patients could assist in the monitoring and management in the intensive care unit (ICU). The Tisdale et al. Risk Score (TRS) is a predictive tool that was developed and validated in a cardiac critical care unit.

OBJECTIVES

The objective of this study was to evaluate the predictive validity (sensitivity and specificity) and likelihood ratios of the TRS in a medical ICU.

METHODS

This was a longitudinal, retrospective, cohort study of consecutive patients who met the inclusion criteria from October 2017 to June 2018 with a sample size of 264 patients. The sample size was derived based on the number of TRS covariates and an exploratory variable. Baseline characteristics and risk factors were documented from electronic health records. The first occurrence of QT_c interval prolongation, defined as a QT_c interval > 500 ms or an increase ≥ 60 ms above baseline, was the primary endpoint.

MAIN RESULTS

The sensitivity and specificity of the TRS for low-risk patients against the moderate-risk and high-risk patients were 97% (95% CI 91-99%) and 16% (95% CI 11-23%), respectively. These results corresponded to a positive likelihood ratio of 1.15 (95% CI 1.07-1.24) and a negative likelihood ratio of 0.20 (95% CI 0.06-0.65).

CONCLUSIONS

In conclusion, the TRS showed a high sensitivity, making it useful in identifying patients at risk of developing QT_c interval prolongation. Furthermore, patients categorized as low risk by the tool can be considered as having minimal risk of developing QT_c interval prolongation. Given the tool's low specificity, it does not reliably identify all patients at low risk of QT_c interval prolongation.

Famotidine induced hypomagnesemia leading to hypocalcemia

Fifty-five-year-old female with a past medical history of gastroesophageal reflux disease was admitted to hospital due to increased confusion, and muscle cramps for last 15 days. She was taking famotidine 20 mg twice a day for the last 2 years. She was alert and oriented to person and place only. She had dry skin, positive Chvostek’s and Trousseau’s sign. Blood work showed 141 mmol/L of sodium, 0.7 mg/dl of creatinine, 5.7 mg/dl of calcium, 0.55 mg/dl of magnesium, low PTH but normal parathyroid related peptide PTHrP, vitamin D (25) and vitamin D (1.25). She was discharged home on electrolyte supplements. She was readmitted with very low calcium and magnesium. Extensive workup including 24 h of urine calcium and magnesium was unimpressive. She was treated with IV therapy and discharged to follow up with nephrology in the clinic, and famotidine was discontinued on second discharge. Her calcium and magnesium levels remained normal, and in a few weeks later, oral electrolyte supplements were discontinued.

Case Report: Investigation and molecular genetic diagnosis of familial hypomagnesaemia

Genetic mutations causing familial hypomagnesaemia syndromes are well-recognised.  Affected patients can present with severe symptoms of hypomagnesaemia, such as seizures or cardiac arrhythmia.  We report an affected child, from a consanguineous family, who presented in the first weeks of life with seizures secondary to hypomagnesaemia, without other associated clinical features.  We performed whole exome sequencing in the affected child and segregation analysis within the family, which revealed a novel homozygous missense mutation in TRPM6, which was confirmed as a heterozygous allele in both parents and two younger siblings who had transient hypomagnesaemia. Using in silico modelling, we provide evidence that the missense variant p.(K1098E) in TRPM6 is pathogenic, as it disrupts stabilising TRP domain interactions. Management of familial hypomagnesaemia relies on prompt recognition, early magnesium replacement and lifelong monitoring.

Total serum magnesium in cats with chronic kidney disease with nephrolithiasis

OBJECTIVES

Magnesium has been 'the forgotten ion' for many years. Over the past decade, however, the role of magnesium in essential physiological functions and several illness conditions have been elucidated. Nevertheless, the investigation of magnesium in cats with chronic kidney disease (CKD) and nephrolithiasis is yet to be determined. The purpose of this study was to investigate whether CKD cats with nephrolithiasis have changes in total serum magnesium concentrations, and whether magnesium disorders may be associated with other electrolyte disturbances, as well as with prognosis. We also aimed to evaluate whether total serum magnesium concentration differs between CKD cats with and without nephrolithiasis.

METHODS

Total serum magnesium concentrations were assessed in 42 cats with CKD with stage 1-4 nephrolithiasis. The correlation between magnesium and other electrolytes, as well as Kaplan-Meier survival analysis, were performed. We also selected 14 control cats with CKD without nephrolithiasis age-matched with 14 cats with CKD with nephrolithiasis.

RESULTS

Hypermagnesemia was observed in 16/42 (38.1%) and hypomagnesemia in 6/42 (14.3%) cats. Serum magnesium abnormalities were observed in cats of all stages, and marked hypermagnesemia was noted in cats with stage 4 CKD with nephrolithiasis (P <0.001). There was a negative correlation between total serum magnesium and ionized calcium (r = -0.64; P <0.01), and a positive correlation between total serum magnesium and serum phosphorus (r = 0.58, P = 0.01). Cats with CKD with nephrolithiasis and hypomagnesemia or hypermagnesemia had higher mortality than those with normal total serum magnesium concentration (P <0.01), regardless of CKD stage. There was no difference in total serum magnesium concentration between CKD cats with and without nephrolithiasis.

CONCLUSIONS AND RELEVANCE

Cats with CKD with nephrolithiasis have magnesium abnormalities. Hypomagnesemia and hypermagnesemia were associated with an increase in mortality, and thus total serum magnesium abnormalities may be used as prognostic factors in these cases.

The incidence, predictors and outcomes of QTc prolongation in critically ill patients

PURPOSE

To study the incidence, predictors and outcomes of QTc prolongation (≥500 ms) during ICU admission.

METHODS

Prospective observational study of patients admitted to a tertiary ICU during a two-month period. We obtained daily data on QTc intervals and arrhythmias from ICU monitors. We performed univariate and multivariable analyses to compare patients who did or did not experience QTc prolongation.

RESULTS

Of the 257 patients, 93 (36.2%) developed ≥1 episode of QTc ≥500 ms. Such patients had higher APACHE II scores (p < .001), received more QT-prolonging medications (p = .002), and more frequently developed non-sustained (<8 beats, p = .007) and sustained ventricular tachycardia (≥8 beats; p < .001). However, after adjustment for confounders, there was no independent association between QTc duration and odds of ventricular tachyarrhythmia (OR = 0.921 [0.593-1.431], p = .715). Moreover, 98% of ventricular tachyarrhythmias resolved spontaneously. Patients with QTc prolongation had longer ICU (p < .001) and hospital length-of-stay (p = .002), and greater ICU (p = .030) and in-hospital mortality (p = .015). No patient experienced sustained Torsades de Pointes or died from ventricular arrhythmia.

CONCLUSIONS

A QTc ≥500 ms likely represents a marker of illness severity modulated by several risk factors, and carries no independent association with clinically-significant ventricular tachyarrhythmias. Thus, cessation of QT-prolonging medications to prevent arrhythmias may lack clinical benefit.

Mg2+ regulation of kinase signaling and immune function

A Mg²⁺-dependent mechanism regulates proximal T cell receptor signaling by modulating ITK activity through a low-affinity Mg²⁺ binding pocket in the catalytic domain. Dietary Mg²⁺ deprivation in mice impairs T cell activation and T cell–mediated immunity against influenza.

Mg²⁺ is required at micromolar concentrations as a cofactor for ATP, enzymatic reactions, and other biological processes. We show that decreased extracellular Mg²⁺ reduced intracellular Mg²⁺ levels and impaired the Ca²⁺ flux, activation marker up-regulation, and proliferation after T cell receptor (TCR) stimulation. Reduced Mg²⁺ specifically impairs TCR signal transduction by IL-2–inducible T cell kinase (ITK) due to a requirement for a regulatory Mg²⁺ in the catalytic pocket of ITK. We also show that altered catalytic efficiency by millimolar changes in free basal Mg²⁺ is an unrecognized but conserved feature of other serine/threonine and tyrosine kinases, suggesting a Mg²⁺ regulatory paradigm of kinase function. Finally, a reduced serum Mg²⁺ concentration in mice causes an impaired CD8⁺ T cell response to influenza A virus infection, reduces T cell activation, and exacerbates morbidity. Thus, Mg²⁺ directly regulates the active site of specific kinases during T cell responses, and maintaining a high serum Mg²⁺ concentration is important for antiviral immunity in otherwise healthy animals.

Effects of diabetic ketoacidosis in the respiratory system

Diabetes affects approximately 30 million persons in the United States. Diabetes ketoacidosis is one of the most serious and acute complications of diabetes. At the time of presentation and during treatment of diabetic ketoacidosis (DKA), several metabolic and electrolyte derangements can ultimately result in respiratory compromise. Most commonly, hypokalemia, hypomagnesemia and hypophosphatemia can eventually lead to respiratory muscles failure. Furthermore, tachypnea, hyperpnea and more severely, Kussmaul breathing pattern can develop. Also, hydrostatic and non-hydrostatic pulmonary edema can occur secondary to volume shifts into the extracellular space and secondary to increased permeability of the pulmonary capillaries. The presence of respiratory failure in patients with DKA is associated with higher morbidity and mortality. Being familiar with the causes of respiratory compromise in DKA, and how to treat them, may represent better outcomes for patients with DKA.

Magnesium and Drugs Commonly Used in Chronic Kidney Disease

As with other electrolytes, magnesium homeostasis depends on the balance between gastrointestinal absorption and kidney excretion. Certain drugs used commonly in patients with CKD can decrease gastrointestinal ingestion and kidney reclamation, and potentially cause hypomagnesemia. Other magnesium-containing drugs such as laxatives and cathartics can induce hypermagnesemia, particularly in those with impaired glomerular filtration and magnesium excretion. In this review, we will discuss the potential magnesium complications associated with a range of commonly encountered drugs in the care of CKD patients, discuss the potential mechanisms, and provide basic clinical recommendations.

Hypomagnesemia in critically ill patients

BACKGROUND

Magnesium (Mg) is essential for life and plays a crucial role in several biochemical and physiological processes in the human body. Hypomagnesemia is common in all hospitalized patients, especially in critically ill patients with coexisting electrolyte abnormalities. Hypomagnesemia may cause severe and potential fatal complications if not timely diagnosed and properly treated, and associate with increased mortality.

MAIN BODY

Mg deficiency in critically ill patients is mainly caused by gastrointestinal and/or renal disorders and may lead to secondary hypokalemia and hypocalcemia, and severe neuromuscular and cardiovascular clinical manifestations. Because of the physical distribution of Mg, there are no readily or easy methods to assess Mg status. However, serum Mg and the Mg tolerance test are most widely used. There are limited studies to guide intermittent therapy of Mg deficiency in critically ill patients, but some empirical guidelines exist. Further clinical trials and critical evaluation of empiric Mg replacement strategies is needed.

CONCLUSION

Patients at risk of Mg deficiency, with typical biochemical findings or clinical symptoms of hypomagnesemia, should be considered for treatment even with serum Mg within the normal range.

Hypoparathyroidism

Hypoparathyroidism is a disease characterized by inadequately low circulating concentrations of parathyroid hormone (PTH) resulting in low calcium levels and increased phosphate levels in the blood. Symptoms of the disease result from increased neuromuscular irritability caused by hypocalcaemia and include tingling, muscle cramps and seizures. The most common cause of the disease is inadvertent removal of, or injury to, the parathyroid glands during neck surgery, followed by genetic, idiopathic and autoimmune aetiologies. Conventional treatment includes activated vitamin D and/or calcium supplements, but this treatment does not fully replace the functions of PTH and can lead to short-term problems (such as hypocalcaemia, hypercalcaemia and increased urinary calcium excretion) and long-term complications (which include nephrocalcinosis, kidney stones and brain calcifications). PTH replacement has emerged as a new treatment option. Clinical trials using human PTH(1-34) and PTH(1-84) showed that this treatment was safe and effective in studies lasting up to 6 years. Recombinant human PTH(1-84) has been approved in the United States and Europe for the management of hypoparathyroidism; however, its effect on long-term complications is still being evaluated. Clinical practice guidelines, which describe the consensus of experts in the field, have been published and recognize the need for more research to optimize care. In this Primer, we summarize current knowledge of the prevalence, pathophysiology, clinical presentation and management of hypoparathyroidism.

Effectiveness and Safety of Magnesium Replacement in Critically Ill Patients Admitted to the Medical Intensive Care Unit in an Academic Medical Center: A Retrospective, Cohort Study

Background:

“Rules of thumb” for the replacement of electrolytes, including magnesium, in critical care settings are used, despite minimal empirical validation of their ability to achieve a target serum concentration. This study’s purpose was to evaluate the effectiveness and safety surrounding magnesium replacement in medically, critically ill patients with mild-to-moderate hypomagnesemia.

Methods:

This was a single-center, retrospective, observational evaluation of episodes of intravenous magnesium replacement ordered for patients with mild-to-moderate hypomagnesemia (1.0-1.9 mEq/L) admitted to a medical intensive care unit from May 2014 to April 2016. The primary effectiveness outcome, achievement of target serum magnesium concentration (≥2 mEq/L) compared to expected achievement using a “rule of thumb” estimation that 1 g intravenous magnesium sulfate raises the magnesium concentration 0.15 mEq/L, was tested using 1-sample z test. Logistic regression analysis was conducted to assess the effect of infusion rate on target achievement.

Results:

Of 152 days on which magnesium replacements were provided for 72 patients, a follow-up serum magnesium concentration was checked within 24 hours in 89 (58.6%) episodes. Of these 89 episodes, serum magnesium concentration reached target in only 49 (59.8%) episodes compared to an expected 89 (100%; P < .0001). There was no significant association between infusion rate and achievement of the target serum magnesium concentration (odds ratio: 0.962, 95% confidence interval: 0.411-2.256).

Conclusions:

Medically, critically ill patients who received nonprotocolized magnesium replacement achieved the target serum magnesium concentration less frequently than the “rule of thumb” estimation predicted.

Genetic causes of hypomagnesemia, a clinical overview

Magnesium is essential to the proper functioning of numerous cellular processes. Magnesium ion (Mg2+) deficits, as reflected in hypomagnesemia, can cause neuromuscular irritability, seizures and cardiac arrhythmias. With normal Mg2+ intake, homeostasis is maintained primarily through the regulated reabsorption of Mg2+ by the thick ascending limb of Henle's loop and distal convoluted tubule of the kidney. Inadequate reabsorption results in renal Mg2+ wasting, as evidenced by an inappropriately high fractional Mg2+ excretion. Familial renal Mg2+ wasting is suggestive of a genetic cause, and subsequent studies in these hypomagnesemic families have revealed over a dozen genes directly or indirectly involved in Mg2+ transport. Those can be classified into four groups: hypercalciuric hypomagnesemias (encompassing mutations in CLDN16, CLDN19, CASR, CLCNKB), Gitelman-like hypomagnesemias (CLCNKB, SLC12A3, BSND, KCNJ10, FYXD2, HNF1B, PCBD1), mitochondrial hypomagnesemias (SARS2, MT-TI, Kearns-Sayre syndrome) and other hypomagnesemias (TRPM6, CNMM2, EGF, EGFR, KCNA1, FAM111A). Although identification of these genes has not yet changed treatment, which remains Mg2+ supplementation, it has contributed enormously to our understanding of Mg2+ transport and renal function. In this review, we discuss general mechanisms and symptoms of genetic causes of hypomagnesemia as well as the specific molecular mechanisms and clinical phenotypes associated with each syndrome.