Hypermagnesemia
Hypermagnesemia is an electrolyte disorder in which there is a high level of magnesium in the blood.[3] Symptoms include weakness, confusion, decreased breathing rate, and decreased reflexes.[1][3] Complications may include low blood pressure and cardiac arrest.[1][4]
Hypermagnesemia | |
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Magnesium | |
Specialty | Endocrinology |
Symptoms | Weakness, confusion, decreased breathing rate[1] |
Complications | Cardiac arrest[1] |
Causes | Kidney failure, treatment induced, tumor lysis syndrome, seizures, prolonged ischemia[1][2] |
Diagnostic method | Blood level > 1.1 mmol/L (2.6 mg/dL)[1][3] |
Treatment | Calcium chloride, intravenous normal saline with furosemide, hemodialysis[1] |
Frequency | Uncommon[3] |
It is typically caused by kidney failure or is treatment induced such as from antacids that contain magnesium.[1][5] Less common causes include tumor lysis syndrome, seizures, and prolonged ischemia.[2] Diagnosis is based on a blood level greater than 1.1 mmol/L (2.6 mg/dL).[1][3] It is severe if levels are greater than 2.9 mmol/L (7 mg/dL).[4] Specific electrocardiogram (ECG) changes may be present.[1]
Treatment involves stopping the magnesium a person is getting.[2] Treatment when levels are very high include calcium chloride, intravenous normal saline with furosemide, and hemodialysis.[1] Hypermagnesemia is uncommon.[3] Rates may be as high as 10% among those in hospital.[2]
Signs and symptoms
- Weakness and nausea
- Impaired breathing
- Hypoventilation
- Low blood pressure
- Low blood calcium[6]
- Abnormal heart rhythms and asystole
- Decreased or absent deep tendon reflexes[7]
- Dizziness
- Sleepiness
Abnormal heart rhythms and asystole are possible complications of hypermagnesemia related to the heart.[8] Magnesium acts as a physiologic calcium blocker, which results in electrical conduction abnormalities within the heart.
Clinical consequences related to serum concentration:
- 4.0 mEq/L decreased reflexes
- >5.0 mEq/L Prolonged atrioventricular conduction
- >10.0 mEq/L Complete heart block
- >13.0 mEq/L cardiac arrest
Note that the therapeutic range for the prevention of the pre-eclampsic uterine contractions is: 4.0-7.0 mEq/L.[9] As per Lu and Nightingale,[10] serum Mg2+ concentrations associated with maternal toxicity (also neonate depression - hypotonia and low Apgar scores) are:
- 7.0-10.0 mEq/L - loss of patellar reflex
- 10.0-13.0 mEq/L - respiratory depression
- 15.0-25.0 mEq/L - altered atrioventricular conduction and (further) complete heart block
- >25.0 mEq/L - cardiac arrest
Causes
Magnesium status depends on three organs: uptake in the intestine, storage in the bone, and excretion in the kidneys. Hypermagnesemia is therefore often due to problems in these organs, mostly intestine or kidney.[11]
Predisposing conditions
- Hemolysis, magnesium concentration in erythrocytes is approximately three times greater than in serum, therefore hemolysis can increase plasma magnesium. Hypermagnesemia is expected only in massive hemolysis.
- Chronic kidney disease, excretion of magnesium becomes impaired when creatinine clearance falls below 30 ml/min. However, hypermagnesemia is not a prominent feature of chronic kidney disease unless magnesium intake is increased.
- Other conditions that can predispose to mild hypermagnesemia are diabetic ketoacidosis, adrenal insufficiency, hypothyroidism, hyperparathyroidism and lithium intoxication.
Metabolism
For a detailed description of magnesium homeostasis and metabolism see hypomagnesemia.
Diagnosis
Hypermagnesemia is diagnosed by measuring the concentration of magnesium in the blood. Concentrations of magnesium greater than 1.1 mmol/L are considered diagnostic.[1]
Treatment
Prevention of hypermagnesemia usually is possible. In mild cases, withdrawing magnesium supplementation is often sufficient. In more severe cases the following treatments are used:
- Intravenous calcium gluconate, because the actions of magnesium in neuromuscular and cardiac function are antagonized by calcium.
Definitive treatment of hypermagnesemia requires increasing renal magnesium excretion through:
- Intravenous diuretics, in the presence of normal kidney function
- Dialysis, when kidney function is impaired and the patient is symptomatic from hypermagnesemia
References
- Soar, J; Perkins, GD; Abbas, G; Alfonzo, A; Barelli, A; Bierens, JJ; Brugger, H; Deakin, CD; Dunning, J; Georgiou, M; Handley, AJ; Lockey, DJ; Paal, P; Sandroni, C; Thies, KC; Zideman, DA; Nolan, JP (October 2010). "European Resuscitation Council Guidelines for Resuscitation 2010 Section 8. Cardiac arrest in special circumstances: Electrolyte abnormalities, poisoning, drowning, accidental hypothermia, hyperthermia, asthma, anaphylaxis, cardiac surgery, trauma, pregnancy, electrocution". Resuscitation. 81 (10): 1400–33. doi:10.1016/j.resuscitation.2010.08.015. PMID 20956045.
- Ronco, Claudio; Bellomo, Rinaldo; Kellum, John A.; Ricci, Zaccaria (2017). Critical Care Nephrology. Elsevier Health Sciences. p. 344. ISBN 9780323511995.
- "Hypermagnesemia". Merck Manuals Professional Edition. Retrieved 28 October 2018.
- Lerma, Edgar V.; Nissenson, Allen R. (2011). Nephrology Secrets. Elsevier Health Sciences. p. 568. ISBN 978-0323081276.
- Romani, Andrea, M.P. (2013). "Chapter 3. Magnesium in Health and Disease". In Astrid Sigel; Helmut Sigel; Roland K. O. Sigel (eds.). Interrelations between Essential Metal Ions and Human Diseases. Metal Ions in Life Sciences. 13. Springer. pp. 49–79. doi:10.1007/978-94-007-7500-8_3. PMID 24470089.
- Cholst, IN; Steinberg, SF; Tropper, PJ; Fox, HE; Segre, GV; Bilezikian, JP (10 May 1984). "The influence of hypermagnesemia on serum calcium and parathyroid hormone levels in human subjects". New England Journal of Medicine. 310 (19): 1221–5. doi:10.1056/NEJM198405103101904. PMID 6709029.
- Khairi, Talal; Amer, Syed; Spitalewitz, Samuel; Alasadi, Lutfi (6 January 2014). "Severe Symptomatic Hypermagnesemia Associated with Over-the-Counter Laxatives in a Patient with Renal Failure and Sigmoid Volvulus". Case Reports in Nephrology. 2014: 560746. doi:10.1155/2014/560746. PMC 3914018. PMID 24563801.
- Schelling, JR (January 2000). "Fatal hypermagnesemia". Clinical Nephrology. 53 (1): 61–5. PMID 10661484.
- Pritchard JA (1955). "The use of the magnesium ion in the management of eclamptogenic toxemias". Surg Gynecol Obstet. 100: 131–140.
- Lu JF, Nightingale CH (2000). "Magnesium sulfate in eclampsia and pre-eclampsia". Clin Pharmacokinet. 38 (4): 305–314. doi:10.2165/00003088-200038040-00002. PMID 10803454.
- Jahnen-Dechent W, Ketteler M (2012). "Magnesium basics" (PDF). Clin Kidney J. 5 (Suppl 1): i3–i14. doi:10.1093/ndtplus/sfr163. PMID 26069819.
External links
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