Iatrogenic magnesium overdose: two case reports

Adjuvant Analgesics in Acute Pain - Evaluation of Efficacy

PURPOSE OF THE REVIEW

Acute postoperative pain impacts a significant number of patients and is associated with various complications, such as a higher occurrence of chronic postsurgical pain as well as increased morbidity and mortality.

RECENT FINDINGS

Opioids are often used to manage severe pain, but they come with serious adverse effects, such as sedation, respiratory depression, postoperative nausea and vomiting, and impaired bowel function. Therefore, most enhanced recovery after surgery protocols promote multimodal analgesia, which includes adjuvant analgesics, to provide optimal pain control. In this article, we aim to offer a comprehensive review of the contemporary literature on adjuvant analgesics in the management of acute pain, especially in the perioperative setting. Adjuvant analgesics have proven efficacy in treating postoperative pain and reducing need for opioids. While ketamine is an established option for opioid-dependent patients, magnesium and α2-agonists have, in addition to their analgetic effect, the potential to attenuate hemodynamic responses, which make them especially useful in painful laparoscopic procedures. Furthermore, α2-agonists and dexamethasone can extend the analgesic effect of regional anesthesia techniques. However, findings for lidocaine remain inconclusive.

Effect of intravenous magnesium on post-operative pain following Latarjet shoulder reconstruction

Background

Single injection ropivacaine interscalene anesthesia (ISA) is frequently used in Latarjet reconstruction to enhance post-operative analgesia. A potential limitation is the occurrence of severe rebound pain on block resolution. We investigated the effect of intravenous magnesium on post-operative pain, particularly at the transition of block resolution to multimodal analgesia.

Methods

Elective patients (n = 40) having Latarjet open shoulder reconstruction were randomised to receive either intravenous magnesium sulphate 50 mg/kg (M) or normal saline (S) before induction. Post-operatively, a standardised analgesic regimen was used, and post-operative pain was recorded using a verbal numerical rating assessment (VNRA) score. Requirement for injected opioid analgesia was recorded.

Results

ISA provided longstanding analgesia in all patients with block duration slightly prolonged in the magnesium group (16.7(1.0) (S), 17.8(1.3) h (M), p = 0.049). Magnesium resulted in less rebound pain following ISA resolution (VNRA 4.0 (0.6) M, 6.2 (0.8) S, p = 0.03) and lower pain intensity at 24 h. Four patients had nausea and two required rescue opioid injection.

Conclusion

Magnesium before Latarjet surgery results in less rebound pain following ropivacaine block and improves post-operative analgesia. Magnesium may be indicated in major upper limb surgery, where significant pain intensity is anticipated.

Level of evidence

Treatment study; Randomised blinded; Level 2.

Adjuvants for balanced anesthesia in ambulatory surgery

Balanced anesthesia relies on the simultaneous administration of different drugs to attain an anesthetic state. The classic triad of anesthesia is a combination of a hypnotic, an analgesic, and a neuromuscular blocker. It is predominantly the analgesic pillar of this triad that became more and more supported by adjuvant therapy. The aim of this approach is to evolve into an opioid-sparing technique to cope with undesirable side effects of the opioids and is fueled by the opioid epidemic. The optimal strategy for balanced general anesthesia in ambulatory surgery must aim for a transition to a multimodal analgesic regimen dealing with acute postoperative pain and ideally reduce the most common adverse effects patients are faced with at home; sore throat, delayed awakening, memory disturbances, headache, nausea and vomiting, and negative behavioral changes. Over the years, this continuum of "multimodal general anesthesia" adopted many drugs with different modes of action. This review focuses on the most recent evidence on the different adjuvants that entered clinical practice and gives an overview of the different mechanisms of action, the potential as opioid-sparing or hypnotic-sparing drugs, and the applicability specifically in ambulatory surgery.

Iatrogenic Hypermagnesemia in a Patient With Preeclampsia Caused by Misinterpretation of the Magnesium Reporting Unit Following Magnesium Sulfate Administration

Because of the lack of standardization, different laboratories report plasma magnesium sulfate or magnesium level in different units, leading to errors in diagnosis and case management; especially when a patient's workup was done in a hospital and then transferred to another hospital. Failure to recognize or understand the reporting units can confuse clinicians and healthcare workers, leading to erroneous interpretations and, consequently, to misdiagnosis of hypermagnesemia or hypomagnesemia. In this report, we present a 32-year-old female patient at 31 weeks of gestation with a history of a multi-substance use disorder who was transferred to the hospital after taking 2.5mg of fentanyl. At the ER, her blood pressure and liver function tests were found to be high. Her albumin was 3.4 g/dl, aspartate transaminase (AST) was 104 IU/l, alanine transaminase (ALT) was 19 IU/l, and anaplastic lymphoma kinase (ALK) phosphatase was 148 IU/l; however, the renal function test was within the normal range. She had a few twitching movements. Her troponin I was high at 648 ng/L, and her B-type natriuretic peptide was 186.1 pg/mL, but her ECG showed a normal result. Magnesium was initiated on a 6 mg bolus, then 2 mg/dl due to preeclampsia concerns. She was transferred to another hospital ICU that used mEq/L as a reporting unit for magnesium and magnesium sulfate levels. The travel nurse did not alert the physician, thinking that magnesium sulfate was still within with therapeutic range of 4.8-8.4 mg/dL. However, considering 4.0-7.0 is the therapeutic range of magnesium sulfate utilizing mEq/L as a reporting unit instead of mg/dL, the patient was found to be at a supratherapeutic level, reaching up to 8.2 mEq/L. The physician discounted the magnesium sulfate. Her blood picture showed normocytic normochromic anemia. Her hemoglobin was 10.9 g/dl, her hematocrit was 33.8%, her mean corpuscular volume (MCV) was 92.5 fL, and her mean corpuscular hemoglobin (MCH) was 29.5 fL. Her platelets were within the normal range (169 10exp9/L). Her temperature was 99.6 F with increased white blood cells (17.7 10e9/L). The fetus was delivered via C-section on the third day of admission in the setting of persistently low fetal heart rates. The patient was extubated on the fourth day of admission and later transferred to the ward and discharged on the fifth day. Monitoring the magnesium level while administrating magnesium sulfate is essential to avoid iatrogenic hypermagnesemia. Utilizing different units at the same laboratory or across different laboratories could lead to the healthcare providers misinterpreting the result, which can lead to misdiagnosing iatrogenic hypermagnesemia. Therefore, standardizing magnesium units across the Clinical Laboratory Improvement Amendments (CLIA) and College of American Pathologists (CAP)-accredited laboratories is highly recommended. A unified unit reporting protocol will allow healthcare providers, constantly and correctly, to interpret the results and avoid misdiagnosing iatrogenic hypermagnesemia, and it will facilitate reporting and exchange of results among the different laboratories.

Postoperative respiratory depression caused by iatrogenic hypermagnesaemia

Hypermagnesaemia is an uncommon electrolyte disorder which can be fatal if not recognised and treated promptly. The signs and symptoms of hypermagnesaemia are non-specific, making it an under-diagnosed cause of cardiovascular dysfunction, hypocalcaemia, and neurological and respiratory depression. Since magnesium homeostasis is handled almost exclusively by the kidneys, symptomatic hypermagnesaemia seldom occurs in the context of normal renal function; when it does, it is usually iatrogenic. Here, we report a case of iatrogenic hypermagnesaemia which presented as respiratory depression, preventing weaning from mechanical ventilation following cardiac surgery in a patient in the early stages of chronic kidney disease. On investigation he was found to have isolated severe hypermagnesaemia, following an intravenous bolus of magnesium sulphate administered intra-operatively to treat tachyarrhythmia. Before administering intravenous magnesium therapeutically, it is important for clinicians to assess renal function and baseline serum magnesium along with other possible risk factors for hypermagnesaemia, and to actively look for signs and symptoms of magnesium toxicity when the patient is receiving therapeutic magnesium.

Hypermagnesemia in a 20-month-old healthy girl caused by the use of a laxative: a case report

Background

Hypermagnesemia can be a fatal condition and should be diagnosed early on. Most reports of hypermagnesemia have been of adults with impaired renal function. We describe the case of a pediatric patient without renal dysfunction who developed severe hypermagnesemia.

Case presentation

A healthy 20-month-old Asian girl presented to our emergency department with episodes of vomiting and a reduced level of consciousness. The neurological examination showed a symmetric decrease in muscle tone, and the deep tendon reflexes were decreased. On admission, her magnesium (Mg) level was 11.0 mg/dL after receiving magnesium oxide for 4 days because of constipation. She was immediately administered calcium gluconate infusion (3.9 mEq), and then was continuously infused with it (0.23 mEq/h) as a Mg antagonist to cardiac side effects. She was kept hydrated with 0.9% sodium chloride to maintain good urine output to excrete the Mg. The level of the serum Mg decreased to 2.4 mg/dL, enabling her to regain consciousness. During 5 years of follow-up, she was neurologically well, without the recurrence of hypermagnesemia.

Conclusions

Even in the absence of significant renal dysfunction, the prescription of a laxative containing Mg for constipation can result in severe hypermagnesemia. In addition, the symptoms of hypermagnesemia are nonspecific, and early diagnosis is difficult unless it is actively suspected.

Antitussive effect of a magnesium infusion during anesthetic emergence in patients with double-lumen endotracheal tube: a randomized controlled trial

Background

A double-lumen endotracheal tube (DLT) inserted into the bronchus can stimulate the respiratory tracts, causing coughing. Opioids have been introduced to prevent emergence cough. However, the administration of a significant opioid dose at the end of surgery may result in undesirable events. Magnesium, common intracellular ion, suppress bronchial smooth muscle contraction and have antitussive effect. We investigated the antitussive effects of a magnesium infusion during anesthetic emergence in patients who underwent thoracic surgery requiring one-lung ventilation (OLV) anesthesia with a DLT.

Methods

One-hundred forty patients undergoing OLV anesthesia with a DLT were enrolled in this prospective, randomized double-blinded trial. In combination with a low dose of remifentanil, patients were randomly allocated to receive either magnesium sulphate (infusion of 15 mg/kg/hour after a single bolus of 30 mg/kg) or normal saline during the operation and emergence. Primary outcomes were the severity and incidence of cough during emergence.

Results

The severity of cough was assessed by the cough severity grading score: 0, no cough; 1, single cough; 2, cough persistence <5 seconds; 3, cough persistence ≥5 seconds. There was a significant difference in the severity score of cough between the groups [median (IQR): 2 (0 to 3) in control group vs. 0 (0 to 1) in magnesium group, P=0.003]. However, there was no significant difference in the overall incidence of cough between both groups [42 (64.6%) in control group vs. 31 (47.7%) in magnesium group, P=0.077].

Conclusions

Magnesium attenuated the severity of cough during emergence after OLV anesthesia using a DLT without adverse events.

Epsom Salt Ingestion Leading to Severe Hypermagnesemia Necessitating Dialysis

BACKGROUND

Hypermagnesemia is an often overlooked electrolyte abnormality that has a myriad of presenting symptoms. It has been observed after both accidental and intentional ingestions of magnesium-containing compounds, and as in the case presented, Epsom salts, which are primarily magnesium sulfate.

CASE REPORT

A 56-year-old man presented to the emergency department reporting weakness after an ingestion of Epsom salts used as a laxative and was found to be bradycardic and hypotensive. He subsequently developed altered mental status and respiratory depression necessitating intubation. His magnesium level was found to be > 3.91 mmol/L (> 9.5 mg/dL). He was given multiple doses of calcium gluconate and generous i.v. fluids with furosemide, with minimal improvement. However, his magnesium level corrected rapidly after initiation of dialysis, and 3 days later he was discharged home in good condition with normal neurologic function. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Keeping a high level of suspicion for, and quickly recognizing, hypermagnesemia allows for prompt initiation of treatment, which can avoid significant hemodynamic or respiratory compromise. Mainstays of treatment are i.v. calcium and i.v. fluids. Loop diuretics may be given as an adjunct as well. Dialysis should be considered in cases of severe hypermagnesemia because it results in rapid correction of magnesium levels.

Effects of magnesium chloride on rocuronium-induced neuromuscular blockade and sugammadex reversal in an isolated rat phrenic nerve-hemidiaphragm preparation: An in-vitro study

BACKGROUND

Magnesium potentiates the effects of nondepolarising muscle relaxants. However, few studies have used magnesium chloride (MgCl2). Sugammadex reverses neuromuscular block by steroidal nondepolarising muscle relaxants.

OBJECTIVES

To assess the effects of MgCl2 on rocuronium-induced neuromuscular blockade and its reversal by sugammadex.

DESIGN

In-vitro experimental study.

SETTING

Animal laboratory, Asan Medical Center, Seoul, South Korea, from 20 March 2016 to 3 April 2016.

ANIMALS

Forty male Sprague Dawley rats.

INTERVENTION

Left phrenic nerve-hemidiaphragms from 40 Sprague Dawley rats were allocated randomly to four groups (1, 2, 3 and 4 mmol l MgCl2 group, n = 10 each). Rocuronium was administered cumulatively until the first twitch of train-of-four (TOF) disappeared completely. Then, equimolar sugammadex was administered.

MAIN OUTCOME MEASURES

The effective concentration (EC) of rocuronium was obtained in each group. After administering sugammadex, recovery of the first twitch height and the TOF ratio were measured for 30 min.

RESULTS

EC50, EC90 and EC95 significantly decreased as the concentration of MgCl2 increased (all P ≤ 0.001), except the comparison between the 3 and 4 mmol l MgCl2 groups. After administration of sugammadex, the maximal TOF ratio (%) was lower in the 4 mmol l MgCl2 group than the 1 mmol l MgCl2 group [median 91.7 interquartile range (83.4 to 95.8) vs. 98.3 interquartile range (92.2 to 103.4), P = 0.049]. The mean time (s) from sugammadex injection to achieving maximal first twitch was significantly prolonged in the 4 mmol l MgCl2 group vs. the 1 mmol l MgCl2 and 2 mmol l MgCl2 groups [1483.9 (± 237.0) vs. 1039.0 (± 351.8) and 926.0 (± 278.1), P = 0.022 and 0.002, respectively].

CONCLUSION

Increases in MgCl2 concentration reduce the ECs of rocuronium. In addition, administering sugammadex equimolar to the administered rocuronium shows limited efficacy as MgCl2 concentration is increased.

TRIAL REGISTRATION

The in-vitro study was not registered in a database.

Bradycardia and Hypotension from Improper Use of Aconite Root: A Case Report and Brief Review

Background: Adverse reactions associated with Chinese herbal medicines (CHMs) are usually the result of unpredictable active/toxic ingredients, inaccurate or mistaken beliefs, or poor supervision. The herb that most commonly induces severe adverse effects in Hong Kong and China is aconite root. More than 200 species of Aconitum plants are used for medicinal purposes, with aconite roots producing analgesic, anti-inflammatory, cardiotonic, and anti-tumor effects. The active components are alkaloids; these can be toxic, but CHM processing methods lower their toxicity and increase the pharmacological efficacy. However, aconite poisoning can result from inadequate decoction time or exceeding the recommended dose. Case Report: Here we report the case of a 92-year-old woman who presented with life-threatening bradycardia and hypotension. This started 1 h after she inappropriately consumed a herbal decoction containing Fuzi for mood fluctuation and health maintenance; Fuzi, an aconite root, has known cardiotoxicity. Electrocardiography showed supraventricular abnormalities, including sinus bradycardia and low-amplitude P waves. After an infusion of normal saline and inotropic agents for 25 h, the clinical manifestations subsided, her sinus rhythm returned to normal, and she was discharged. At follow-up 2 weeks later, she was in good health and had ceased taking any CHM. Conclusions: Standardized processing methods, stringent regulations, and cooperation between health professions can ensure medication safety and establish a fully-fledged operating process for these valuable drugs. We hope this report will help establish correct attitudes toward CHM and will assist Traditional Chinese Medicine practitioners to become more familiar with Aconitum plants.

Magnesium Replacement to Protect Cardiovascular and Kidney Damage? Lack of Prospective Clinical Trials

Patients with advanced chronic kidney disease exhibit an increase in cardiovascular mortality. Recent works have shown that low levels of magnesium are associated with increased cardiovascular and all-cause mortality in hemodialysis patients. Epidemiological studies suggest an influence of low levels of magnesium on the occurrence of cardiovascular disease, which is also observed in the normal population. Magnesium is involved in critical cellular events such as apoptosis and oxidative stress. It also participates in a number of enzymatic reactions. In animal models of uremia, dietary supplementation of magnesium reduces vascular calcifications and mortality; in vitro, an increase of magnesium concentration decreases osteogenic transdifferentiation of vascular smooth muscle cells. Therefore, it may be appropriate to evaluate whether magnesium replacement should be administered in an attempt to reduce vascular damage and mortality in the uremic population In the present manuscript, we will review the magnesium homeostasis, the involvement of magnesium in enzymatic reactions, apoptosis and oxidative stress and the clinical association between magnesium and cardiovascular disease in the general population and in the context of chronic kidney disease. We will also analyze the role of magnesium on kidney function. Finally, the experimental evidence of the beneficial effects of magnesium replacement in chronic kidney disease will be thoroughly described.

Fatal Hypermagnesemia Due to Laxative Use

We report a case of fatal hypermagnesemia in a 53-year-old woman admitted for acute exacerbation of chronic obstructive pulmonary disease and with a history of chronic constipation treated regularly with magnesium-containing laxatives. On admission, her magnesium level was 2.0mg/dL, which rose to a peak of 10.8mg/dL despite hydration and diuresis in the presence of a normal kidney function. Continuous renal replacement therapy was promptly initiated, which reduced her serum magnesium levels, but her condition continued to deteriorate precipitously progressing to shock leading to oligoanuric renal failure, and she died 2 days later. A review of the literature shows that though rare and often unsuspected, severe hypermagnesemia frequently results in death even in individuals with normal renal function despite renal replacement therapy. In patients with constipation, retention of magnesium-based laxative in the gut apparently serves as a reservoir for continuous magnesium absorption and contributes to mortality.

Efficacy of Magnesium Sulphate as an Adjunct to Ropivacaine in Local Infiltration for Postoperative Pain Following Lower Segment Caesarean Section

INTRODUCTION

Intravenous and peri-articular magnesium has been shown to reduce perioperative analgesic consumption. With this background, subcutaneous infiltration was hypothesized to potentiate the subcutaneous infiltration of local anaesthetic agent.

AIM

To comparatively evaluate the efficacy of magnesium sulphate as an adjunct to ropivacaine in local infiltration for postoperative pain following lower segment cesarean section.

MATERIALS AND METHODS

Sixty parturients undergoing cesarean delivery were randomized to either group A or B in a double blinded manner. After uterine and muscle closure but before skin closure, Group A was administered local subcutaneous wound infiltration of Injection (Inj) ropivacaine 0.75% 150 milligram (mg) or 20 millilitres(ml) whereas, group B patients were given a local subcutaneous wound infiltration of Inj magnesium sulphate 750 mg (1.5 ml of Inj 50% Magnesium sulphate) added to Inj ropivacaine 0.75% (18.5 ml) making a total volume of 20 ml. In postoperative period, Heart rate (HR), Mean Arterial Pressure (MAP), Visual Analogue Score (VAS), supplemental analgesic consumption and timing of each subsequent analgesic was noted for the initial 24 hours.

RESULTS

There was no difference in the timings for the requirement of first Intravenous (IV) rescue analgesic among both the groups (p=0.279). However, the need for 2(nd) and 3(rd) doses of rescue analgesics was significantly later in group B and the difference was statistically significant with p-value of 0.034 and 0.031 respectively. The number of patients who were administered 2(nd), 3(rd) and 4(th) doses of rescue analgesics was significantly greater in group A as compared to group B. None of the patients in group B needed more than 4 doses of rescue analgesia while in group A, 5 patients were administered a rescue analgesic for 5(th) time. The cumulative analgesic requirement in the initial 24 hours was also greater in group A as compared to group B and the difference was statistically significant (p =0.01). The incidence of adverse effects was similar in both the groups.

CONCLUSION

Subcutaneous infiltration of magnesium along with local anaesthetic prolongs the analgesic efficacy of local anaesthetic and is not associated with any significant adverse effects.

Iatrogenic magnesium toxicity following intravenous infusion of magnesium sulfate: risks and strategies for prevention

A 65-year-old man being treated with radiotherapy and chemotherapy for recurrent colonic adenocarcinoma was admitted for management of hypokalaemia and hypomagnesaemia secondary to diarrhoea. He was treated with intravenous infusions of potassium chloride and magnesium sulfate. Following an infusion of magnesium sulfate, he experienced a sudden neurological deterioration. A CT of the head revealed no haemorrhage or evidence of acute ischaemic injury. Results of serum biochemistry later that day revealed an elevated magnesium level. Iatrogenic magnesium toxicity was suspected. Further discussions between the pharmacist and ward staff confirmed that a medication error had been made in the preparation of the infusion resulting in an overdose of intravenous magnesium.

Magnesium basics

As a cofactor in numerous enzymatic reactions, magnesium fulfils various intracellular physiological functions. Thus, imbalance in magnesium status-primarily hypomagnesaemia as it is seen more often than hypermagnesaemia-might result in unwanted neuromuscular, cardiac or nervous disorders. Measuring total serum magnesium is a feasible and affordable way to monitor changes in magnesium status, although it does not necessarily reflect total body magnesium content. The following review focuses on the natural occurrence of magnesium and its physiological function. The absorption and excretion of magnesium as well as hypo- and hypermagnesaemia will be addressed.

A case report of bittern intoxication

Bittern is made from marine water after extraction of salt, and its major components include magnesium chloride, magnesium sulfate, potassium chloride, sodium chloride and magnesium bromide. For a long time, it has been used as the main ingredient of tofu coagulant and chemical weapons. A 73-year-old woman arrived to the emergency department after a suicide attempt by drinking an unknown amount bittern. She complained of dizziness, general weakness, and altered mental state (Glasgow Coma Scale (GCS) 13/15). The brain computed tomography (CT) and magnetic resonance imaging (MRI) showed no abnormality. But blood chemistry showed hypermagnesemia ([Mg(2+)] 7.8 mEq/L) and hypernatremia ([Na(+)] 149 mEq/L). Electrocardiograph showed QT prolongation of 0.482 s. Electrolyte imbalances were corrected following adequate fluid therapy and injection of calcium gluconate. The patient recovered/was subsequently discharged without any complications. Electrolyte imbalances are a common presentation following bittern poisoning. Severe side effects like respiratory depression, hypotension, arrhythmia, bradycardia, and cardiac arrest can also occur. Patients will require immediate fluid therapy and correction of electrolyte imbalances. The symptoms vary depending on the electrolyte levels. It is mandatory to closely monitor the electrolyte levels and electrocardiograph in these patients.

Severe Symptomatic Hypermagnesemia Associated with Over-the-Counter Laxatives in a Patient with Renal Failure and Sigmoid Volvulus

Hypermagnesemia is an uncommon but a potentially serious clinical condition. Over-the-counter magnesium containing products are widely used as antacids or laxatives. Although generally well tolerated in patients with normal renal function, their unsupervised use in the elderly can result in severe symptomatic hypermagnesemia, especially in those patients with concomitant renal failure and bowel disorders. We report a case of severe symptomatic hypermagnesemia associated with over-the-counter laxatives in a 70-year-old male patient with renal failure and sigmoid volvulus, who was successfully treated with hemodialysis.

The effect of intravenous magnesium sulfate infusion on sensory spinal block and postoperative pain score in abdominal hysterectomy

AIM

The aim of this study was to investigate the effect of i.v. infusion of magnesium sulphate during spinal anesthesia on duration of spinal block and postoperative pain.

METHODS

Forty ASA physical status I and status II, aged between 18 and 65, female patients undergoing abdominal hysterectomy under spinal anesthesia were enrolled in this study. Patients in the magnesium group (Group M, n = 20) received magnesium sulphate 65 mg kg(-1) infusion in 250 mL 5% dextrose at 3.5 mL/min rate, and control group (Group C, n = 20) received at the same volume of saline during operation in a double-blind randomized manner. Duration of sensory and motor block, systolic, diastolic, and mean arterial blood pressures, heart rates, pain scores (VAS values), and side effects were recorded for each patient. Blood and CSF samples were taken for analysis of magnesium concentrations.

RESULTS

Regression of sensorial block was longer in Group M when compared with that in Group C (175 ± 39 versus 136 ± 32 min) (P < 0.01). The VAS scores were lower in Group M than those in Group C at the 2 time points postoperatively (P < 0.01).

CONCLUSION

65 mg kg(-1) of magnesium sulphate i.v. infusion under spinal anesthesia prolongs spinal sensorial block duration and decreases pain VAS scores without complication in patients undergoing abdominal hysterectomy.

Severe hypermagnesemia presenting with abnormal electrocardiographic findings similar to those of hyperkalemia in a child undergoing peritoneal dialysis

In this report, we present a pediatric case of severe symptomatic hypermagnesemia resulting from the use of magnesium oxide as a laxative in a child undergoing continuous cyclic peritoneal dialysis for end-stage renal disease. The patient showed abnormal electrocardiography (ECG) findings, such as tall T waves, a widened QRS complex, and irregular conduction, which were initially misdiagnosed as hyperkalemia; later, the correct diagnosis of hypermagnesemia was obtained. Emergent hemodialysis successfully returned the serum magnesium concentration to normal without complications. When abnormal ECG changes are detected in patients with renal failure, hypermagnesemia should be considered.

[Magnesium disorders]

Extracellular content in magnesium represents about 1% of total body content, of which plasma magnesium is thus a poor reflect. Hypomagnesaemia is defined by a value lesser than 0.65mmol/L. Its incidence in hospitalized patients ranges between 10 and 15%. Identification of the physiopathology of hypomagnesaemia relies first upon concomitant measurement of plasma and urinary magnesium concentration. Daily magnesium excretion lesser than 1mmol/L or EFMg lesser than 1% sign extra renal origin, due to either low magnesium intake, low intestinal absorption of magnesium or derivation of extracellular magnesium toward bone, such as in bone reparation process after hyperparathyroidism surgery. Daily magnesium excretion higher than 2mmol/L concomitant to hypomagnesaemia indicates native or acquired renal loss of magnesium. Congenital renal and extra-renal losses of magnesium are mainly related to rare monogenic disease, and are inconstantly associated with a renal loss of sodium, potassium and calcium. Recent progress in the genetics of this rare diseases have greatly improved the knowledge about proteins involved in intestinal abortion, renal renal tubular re-absorption of magnesium and its regulations. Hypermagnesemia is a rarer metabolic disorder than hypomagnesemia (about 5% of hospitalized patients). Asymptomatic below 2mmol/L, it progressively alters neuromuscular transmission, autonomic sympathic activity and cardiac conduction, with vital risk above 7mol/L. It is due to acute magnesium input into extracellular volume most often associated with a decrease in glomerular filtration rate, limiting the high physiological ability to excrete magnesium input.

Magnesium sulfate as an adjunct therapy in the management of severe generalized tetanus in a dog

OBJECTIVE

To describe the use of magnesium sulfate in a case of generalized tetanus in a dog.

CASE SUMMARY

A 1.5-year-old golden retriever was presented for a digital wound on the right thoracic limb and clinical signs associated with generalized tetanus. Initial case management consisted of wound debridement, treatment with metronidazole, tetanus immunoglobulin, methocarbamol, airway management via tracheostomy, and nursing care. Sedation to control severe muscle spasms became insufficient despite increasing doses of benzodiazepine, methocarbamol, and barbiturate continuous rate infusions. A magnesium sulfate continuous rate infusion was instituted on day 7 and muscle rigidity improved within 16 hours allowing discontinuation of sedative infusions over the subsequent 2 days. Clinical improvement continued and the dog was discharged on day 14.

NEW OR UNIQUE INFORMATION PROVIDED

This case demonstrates the use of supraphysiologic magnesium in the treatment of severe generalized tetanus with a positive outcome. No clinical signs associated with magnesium toxicity were noted during the course of therapy. Magnesium sulfate should be considered as a potential adjunct therapy in the management of spastic paralysis caused by severe tetanus in dogs.

A case of cardiopulmonary arrest caused by laxatives-induced hypermagnesemia in a patient with anorexia nervosa and chronic renal failure

We report a case of laxatives induced severe hypermagnesemia complicated with cardiopulmonary arrest. A 55-year-old woman, with nephritic syndrome and anorexia nervosa, was later transported to our emergency room (ER) because of oliguria and consciousness disturbance. During transfer to the intensive care unit from the ER, cardiopulmonary arrest suddenly occurred. Cardiopulmonary resuscitation was immediately performed, and spontaneous circulation was restored after 3 min. Thereafter, administration of dopamine, norepinephrine, and epinephrine was required to maintain systolic blood pressure at 80 mmHg. Arterial blood gas analysis showed severe metabolic alkalosis, and blood biochemical tests revealed hypermagnesemia (serum magnesium concentration, 18.5 mg/dl) and renal dysfunction. Continuous infusion of diuretics followed by massive hydration and continuous hemodiafiltration (CHDF) was started. Five days after starting CHDF, magnesium concentration was almost normalized and administration of catecholamine was stopped. It was thought that progression of renal dysfunction that occurred in the patient taking a magnesium product for chronic constipation caused reduction in magnesium excretion ability, resulting in hypermagnesemia-induced cardiopulmonary arrest. To avoid a rebound phenomenon following magnesium flux from cells, continuous blood purification seems to be an effective treatment for symptomatic hypermagnesemia.

Serum magnesium concentration in children with functional constipation treated with magnesium oxide

AIM: To determine whether hypermagnesemia recently reported in adult patients possibly develops in children with functional constipation taking daily magnesium oxide.

METHODS: We enrolled 120 patients (57 male and 63 female) aged 1-14 years old (median: 4.7 years) with functional constipation from 13 hospitals and two private clinics. All patients fulfilled the Rome III criteria for functional constipation and were treated with daily oral magnesium oxide for at least 1 mo. The median treatment dose was 600 (500-800) mg/d. Patients were assessed by an interview and laboratory examination to determine possible hypermagnesemia. Serum magnesium concentration was also measured in sex- and age-matched control subjects (n = 38).

RESULTS: In the constipation group, serum magnesium concentration [2.4 (2.3-2.5) mg/dL, median and interquartile range] was significantly greater than that of the control group [2.2 (2.0-2.2) mg/dL] (P < 0.001). The highest value was 3.2 mg/dL. Renal magnesium clearance was significantly increased in the constipation group. Serum magnesium concentration in the constipation group decreased significantly with age (P < 0.01). There was no significant correlation between the serum level of magnesium and the duration of treatment with magnesium oxide or the daily dose. None of the patients had side effects associated with hypermagnesemia.

CONCLUSION: Serum magnesium concentration increased significantly, but not critically, after daily treatment with magnesium oxide in constipated children with normal renal function.

Effects of magnesium sulphate on intraoperative anaesthetic requirements and postoperative analgesia in gynaecology patients receiving total intravenous anaesthesia

BACKGROUND

This randomized, double-blind, prospective study was undertaken to evaluate the effects of magnesium sulphate on anaesthetic requirements and postoperative analgesia in patients undergoing total i.v. anaesthesia (TIVA).

METHODS

Fifty patients who underwent gynaecological surgery were randomly divided into two groups. Before induction of anaesthesia, the magnesium group (Group M) received magnesium sulphate 50 mg kg(-1) i.v. as a bolus and then 15 mg kg(-1) h(-1) i.v. by continuous infusion. The control group (Group S) received the same amount of isotonic saline. TIVA (propofol+remifentanil) was administered under bispectral index monitoring during anaesthesia induction and maintenance. Rocuronium was administered before orotracheal intubation and during surgery when the train-of-four count was 2 or more. After operation, patient-controlled analgesia with a solution of ketorolac and morphine was used and the consumption of this solution was recorded. Pain scores at rest and upon movement were evaluated 30 min, 4, 24, and 48 h after surgery.

RESULTS

Patients in Group M required less rocuronium than those in Group S [mean (SD) 0.44 (0.09) vs 0.35 (0.07) microg kg(-1) min(-1), P<0.05]. The total amounts of propofol and remifentanil administered were similar in the two groups. Postoperative pain scores, cumulative analgesic consumption, and shivering incidents were significantly lower in Group M (P<0.05). Mean arterial pressure just after intubation and during the immediate postoperative period was also significantly lower in Group M (P<0.05).

CONCLUSIONS

I.v. magnesium sulphate during TIVA reduced rocuronium requirement and improved the quality of postoperative analgesia.

Thiopental and halothane dose-sparing effects of magnesium sulphate in dogs

OBJECTIVE

To evaluate the effect of pre- and intraoperatively administered magnesium sulphate (MgSO(4)) on the induction dose of thiopental and of halothane for maintenance of anaesthesia in dogs undergoing ovariohysterectomy (OHE).

STUDY DESIGN

Prospective, double-blind, randomized, placebo-controlled study.

ANIMALS

Forty-six healthy, ASA physical status 1 dogs, scheduled for elective OHE.

METHODS

The dogs were randomly assigned to receive a bolus of 50 mg kg(-1) MgSO(4) intravenously (IV), just before induction of anaesthesia, followed by a constant rate infusion (CRI) of 12 mg kg(-1) hour(-1) MgSO(4) intraoperatively (group Mg, n = 27) or a placebo bolus and CRI of 0.9% sodium chloride (NaCl) (group C, n = 19), approximately 30 minutes after premedication with acepromazine (0.05 mg kg(-1), intramuscularly, IM) and carprofen (4 mg kg(-1), subcutaneously, SC). Anaesthesia was induced with thiopental administered to effect and maintained with halothane in oxygen. End-tidal halothane (ET(hal)) was adjusted to achieve adequate depth of anaesthesia. Blood samples were obtained pre- and postoperatively for measurement of total serum magnesium concentration.

RESULTS

The mean dose of thiopental was statistically lower (p < 0.0005) and the mean standardized ET(hal) concentration and end-tidal carbon dioxide partial pressure (Pe'CO(2)) areas under the curve were statistically smaller (p < 0.0005 and 0.014 respectively) in group Mg. Postoperatively the mean total serum magnesium concentration was statistically higher than the preoperative value (p < 0.0005) in group Mg, but not in group C. Nausea, associated with the MgSO(4) bolus injection, was observed in six dogs in group Mg, two of which vomited prior to induction of anaesthesia.

CONCLUSIONS AND CLINICAL RELEVANCE

Magnesium sulphate administration reduced the induction dose of thiopental and ET(hal) concentration for maintenance of anaesthesia in dogs undergoing OHE. Observed side effects were nausea and vomiting.

Achieved serum magnesium concentrations and occurrence of delayed cerebral ischaemia and poor outcome in aneurysmal subarachnoid haemorrhage

BACKGROUND

Magnesium therapy probably reduces the frequency of delayed cerebral ischaemia (DCI) in subarachnoid haemorrhage (SAH) but uncertainty remains about the optimal serum magnesium concentration. We assessed the relationship between serum magnesium concentrations achieved with magnesium sulphate therapy 64 mmol/day and the occurrence of DCI and poor outcome in patients with SAH.

METHODS

Differences in magnesium concentrations between patients with and without DCI and with and without poor outcome were calculated. Quartiles of last serum magnesium concentrations before the onset of DCI, or before the median day of DCI in patients without DCI, were related to the occurrence of DCI and poor outcome at 3 months using logistic regression.

RESULTS

Compared with the lowest quartile of serum magnesium concentration (1.10-1.28 mmol/l), the risk of DCI was decreased in each of the higher three quartiles (adjusted odds ratio (OR) in each quartile 0.2; lower 95% CI 0.0 to 0.1; upper limit 0.8 to 0.9). The OR for poor outcome was 1.8 (95% CI 0.5 to 6.9) in the second quartile, 1.0 (95% CI 0.2 to 4.5) in the third quartile and 4.9 (95% CI 1.2 to 19.7) in the highest quartile.

DISCUSSION

Magnesium sulphate 64 mmol/day results in a stable risk reduction of DCI over a broad range of achieved serum magnesium concentrations, and strict titration of the dosage therefore does not seem necessary. However, concentrations < or = 1.28 mmol/l could decrease the effect on DCI while concentrations > or = 1.62 might have a negative effect on clinical outcome.

Successful resuscitation of hypermagnesaemic asystolic cardiac arrest with the use of early transvenous cardiac pacemaker: a case report

A 63 year old woman presented to the emergency department (ED) with 1 week of progressive dyspnoea, constipation, and generalized weakness. She had undergone spinal fustion surgery 10 days previously, and had a history of chronic renal insufficiency. The patient had been using milk of magnesia and magnesium citrate in unknown amounts to alleviate her constipation over this time frame. During her ED stay she became progressively hypotensive and bradycardic, and despite aggressive resuscitative measures she suffered an asystolic arrest 1 hour into her ED course. She was resuscitated with conventional therapy, but her haemodynamic profile did not improve significantly until transvenous cardiac pacing was employed. Her magnesium level was 10.4 mmol/l. Treatment of magnesium overload has focused upon haemodialysis, forced diuresis, and the use of intravenous calcium salts. Case reports have previously documented survival of moderately to severely ill patients when these modalities have been used. Likewise, failure of resuscitation despite use of these methods has been previously noted. To our knowledge, this is the first reported case clearly demonstrating the efficacy of transvenous cardiac pacing to successfully resuscitate a patient upon whom multiple vasopressors, fluids, and calcium previously had no clear effect.

Hypermagnesemia induced by massive cathartic ingestion in an elderly woman without pre-existing renal dysfunction

A 76-year-old woman was referred to our hospital for unresponsiveness and hypotension. She had developed constipation that had led to ileus and had received 34 g of magnesium citrate (Magcolol P) orally the day before. She was lethargic, her blood pressure was less than 50 mmHg, and electrocardiogram (ECG) revealed sinus arrest with junctional escape rhythm. Her serum concentration of magnesium (Mg) was markedly elevated (16.6 mg/dl =13.7 mEq/l). Emergency colonoscopy revealed ischemic colitis. As her condition ameliorated, her renal function returned to normal. Hence, the present case suggests that severe hypermagnesemia can occur in the absence of pre-existing renal dysfunction in elderly patients with gastrointestinal diseases.

Magnesium deficiency in critical illness

Magnesium (Mg) deficiency commonly occurs in critical illness and correlates with a higher mortality and worse clinical outcome in the intensive care unit (ICU). Magnesium has been directly implicated in hypokalemia, hypocalcemia, tetany, and dysrhythmia. Moreover, Mg may play a role in acute coronary syndromes, acute cerebral ischemia, and asthma. Magnesium regulates hundreds of enzyme systems. By regulating enzymes controlling intracellular calcium, Mg affects smooth muscle vasoconstriction, important to the underlying pathophysiology of several critical illnesses. The principle causes of Mg deficiency are gastrointestinal and renal losses; however, the diagnosis is difficult to make because of the limitations of serum Mg levels, the most common assessment of Mg status. Magnesium tolerance testing and ionized Mg2+ are alternative laboratory assessments; however, each has its own difficulties in the ICU setting. The use of Mg therapy is supported by clinical trials in the treatment of symptomatic hypomagnesemia and preeclampsia and is recommended for torsade de pointes. Magnesium therapy is not supported in the treatment of acute myocardial infarction and is presently undergoing evaluation for the treatment of severe asthma exacerbation, for the prevention of post-coronary bypass grafting dysrhythmias, and as a neuroprotective agent in acute cerebral ischemia.

Fatal hypermagnesemia caused by an Epsom salt enema: a case illustration

The authors describe a case of fatal hypermagnesemia caused by an Epsom salt enema. A 7-year-old male presented with cardiac arrest and was found to have a serum magnesium level of 41.2 mg/dL (33.9 mEq/L) after having received an Epsom salt enema earlier that day. The medical history of Epsom salt, the common causes and symptoms of hypermagnesemia, and the treatment of hypermagnesemia are reviewed. The easy availability of magnesium, the subtle initial symptoms of hypermagnesemia, and the need for education about the toxicity of magnesium should be of interest to physicians.

Iatrogenic acute hypermagnesemia after total parenteral nutrition infusion mimicking septic shock syndrome: two case reports

Two premature newborn infants developed extreme magnesium toxicity while receiving total parenteral nutrition (TPN) infusion. Both patients exhibited acute hypotonia, apnea, hypotension, and refractory bradycardia mimicking septic shock syndrome. The complete blood count was normal, and blood cultures were negative. Serum magnesium concentration in 1 patient was 43.1 mEq/L and in the other patient was 45 mEq/L (normal values for serum magnesium being 1.6-2.1 mEq/L). Hypermagnesemia resulted from malfunction of an automated TPN mixing device. Unexplained sudden onset of apnea, refractory bradycardia, and hypotension should raise suspicions of hypermagnesemia, a reversible condition if identified and treated early.

Correction of ionized plasma magnesium during cardiopulmonary bypass reduces the risk of postoperative cardiac arrhythmia

We conducted this randomized controlled trial to determine whether the intraoperative measurement and correction of ionized plasma magnesium can reduce the risk of cardiac arrhythmia after cardiopulmonary bypass. Eighty-five patients presenting for coronary artery bypass grafting were randomly assigned either to the magnesium-corrected group, which received magnesium sulfate on the basis of measured levels of ionized plasma magnesium (n = 43), or to the control group, in which magnesium levels were identified but not corrected (n = 42). Ionized magnesium was determined with an ion-selective electrode with minimal delay, and further samples were taken for laboratory analysis of total plasma magnesium. All patients had Holter electrocardiogram monitoring for 72 h after surgery. Total hypomagnesemia (45 patients; 53% of all patients) was more common than ionized hypomagnesemia (11 patients; 13%) before cardiopulmonary bypass. Both total and ionized magnesium levels declined further during the course of cardiopulmonary bypass in the control group. The incidence of ventricular tachycardia in the first 24 h was less frequent in the magnesium-corrected group (3 patients; 7%) than the control group (12 patients, 30%; P < 0.01). Patients in the magnesium-corrected group were more likely to display continuous sinus rhythm (Lown Grade 0) in the first 24 h (14 patients; 34%) than patients in the control group (2 patients, 5%; P < 0.001). Our results suggest that the intraoperative correction of ionized magnesium is associated with a reduction in postoperative ventricular arrhythmia in cardiac surgical patients.

IMPLICATIONS

In this study the correction of ionized plasma magnesium during cardiopulmonary bypass was guided by measurements from an ion-selective electrode. This intervention resulted in a reduction in the incidence of postoperative ventricular tachycardia and an increased frequency of continuous sinus rhythm. Ion-selective electrodes constitute a convenient near-patient test, providing a basis for the targeted replacement of ionized plasma magnesium.

Prescribing errors involving medication dosage forms

CONTEXT

Prescribing errors involving medication dose formulations have been reported to occur frequently in hospitals. No systematic evaluations of the characteristics of errors related to medication dosage formulation have been performed.

OBJECTIVE

To quantify the characteristics, frequency, and potential adverse patient effects of prescribing errors involving medication dosage forms.

DESIGN

Evaluation of all detected medication prescribing errors involving or related to medication dosage forms in a 631-bed tertiary care teaching hospital.

MAIN OUTCOME MEASURES

Type, frequency, and potential for adverse effects of prescribing errors involving or related to medication dosage forms.

RESULTS

A total of 1,115 clinically significant prescribing errors involving medication dosage forms were detected during the 60-month study period. The annual number of detected errors increased throughout the study period. Detailed analysis of the 402 errors detected during the last 16 months of the study demonstrated the most common errors to be: failure to specify controlled release formulation (total of 280 cases; 69.7%) both when prescribing using the brand name (148 cases; 36.8%) and when prescribing using the generic name (132 cases; 32.8%); and prescribing controlled delivery formulations to be administered per tube (48 cases; 11.9%). The potential for adverse patient outcome was rated as potentially "fatal or severe" in 3 cases (0.7%), and "serious" in 49 cases (12.2%). Errors most commonly involved cardiovascular agents (208 cases; 51.7%).

CONCLUSIONS

Hospitalized patients are at risk for adverse outcomes due to prescribing errors related to inappropriate use of medication dosage forms. This information should be considered in the development of strategies to prevent adverse patient outcomes resulting from such errors.

Hypermagnesemia-induced fatality following epsom salt gargles(1)

Hypermagnesemia is a rare cause of coma in a patient with normal renal function. When present, it is often because of iatrogenic medication overdose. We report a fatal case of chronic Epsom salt gargles for halitosis that produced a serum magnesium of 23.6 mg/dL (9.8 mmol/L) and resulted in coma. We review the wide presentation of hypermagnesemia from subtle neurologic and cardiovascular signs to the major life-threatening clinical manifestations of shock, dysrhythmias, coma, and cardiopulmonary arrest despite emergency dialysis.

Hypermagnesemia in a pediatric patient

IMPLICATIONS

A high blood magnesium level is a rare but life-threatening event. This case report describes an accidental overdose of magnesium that occurred in an 18-month-old girl during a routine operation. The effects of high magnesium levels and its treatment are explained in detail.