Hypermagnesemia is an

electrolyte disorder Electrolyte imbalance, or water-electrolyte imbalance, is an abnormality in the concentration of electrolytes in the body. Electrolytes play a vital role in maintaining homeostasis in the body. They help to regulate heart and neurological function ...

in which there is a high level of

magnesium Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 ...

in the blood. Symptoms include

weakness Weakness is a symptom of many different medical conditions. The causes are many and can be divided into conditions that have true or perceived muscle weakness. True muscle weakness is a primary symptom of a variety of skeletal muscle diseases, ...

confusion In psychology, confusion is the quality or emotional state of being bewildered or unclear. The term "acute mental confusion"

, decreased breathing rate, and decreased reflexes. Hypermagnesemia can greatly increase the chances of adverse cardiovascular events. Complications may include

low blood pressure Hypotension, also known as low blood pressure, is a cardiovascular condition characterized by abnormally reduced blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood and is ...

and

cardiac arrest Cardiac arrest (also known as sudden cardiac arrest CA is when the heart suddenly and unexpectedly stops beating. When the heart stops beating, blood cannot properly Circulatory system, circulate around the body and the blood flow to the ...

. It is typically caused by

kidney failure Kidney failure, also known as renal failure or end-stage renal disease (ESRD), is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney fa ...

or is treatment-induced such as from

antacids An antacid is a substance which neutralizes stomach acidity and is used to relieve heartburn, indigestion, or an upset stomach. Some antacids have been used in the treatment of constipation and diarrhea. Marketed antacids contain salts o ...

or supplements that contain magnesium. Less common causes include

tumor lysis syndrome Tumor lysis syndrome (TLS) is a group of metabolic abnormalities that can occur as a complication from the treatment of cancer, where large amounts of tumor cells are killed off ( lysed) from the treatment, releasing their contents into the blood ...

seizures A seizure is a sudden, brief disruption of brain activity caused by abnormal, excessive, or synchronous neuronal firing. Depending on the regions of the brain involved, seizures can lead to changes in movement, sensation, behavior, awareness, o ...

, and prolonged

ischemia Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems ...

. Diagnosis is based on a blood level of magnesium greater than 1.1 mmol/L (2.6 mg/dL). It is severe if levels are greater than 2.9 mmol/L (7 mg/dL). Specific electrocardiogram (ECG) changes may be present. Treatment involves stopping the magnesium a person is getting. Treatment when levels are very high include

calcium chloride Calcium chloride is an inorganic compound, a Salt (chemistry), salt with the chemical formula . It is a white crystalline solid at room temperature, and it is highly soluble in water. It can be created by neutralising hydrochloric acid with cal ...

intravenous normal saline Saline (also known as saline solution) is a mixture of sodium chloride (salt) and water. It has a number of uses in medicine including cleaning wounds, removal and storage of contact lenses, and help with dry eyes. By injection into a vein, i ...

with

furosemide Furosemide, sold under the brand name Lasix among others, is a loop diuretic medication used to treat edema due to heart failure, liver scarring, or kidney disease. Furosemide may also be used for the treatment of high blood pressure. It can ...

, and

hemodialysis Hemodialysis, American and British English spelling differences#ae and oe, also spelled haemodialysis, or simply ''"'dialysis'"'', is a process of filtering the blood of a person whose kidneys are not working normally. This type of Kidney dialys ...

. Hypermagnesemia is uncommon. Rates among hospitalized patients in renal failure may be as high as 10%.

Signs and symptoms

Symptoms include

confusion In psychology, confusion is the quality or emotional state of being bewildered or unclear. The term "acute mental confusion"

, decreased breathing rate, and decreased reflexes. As well as nausea,

low blood calcium Hypocalcemia is a medical condition characterized by low calcium levels in the blood serum. The normal range of blood calcium is typically between 2.1–2.6 mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L), while levels less than 2.1 mm ...

, abnormal heart rhythms and

asystole Asystole (New Latin, from Greek privative a "not, without" + ''systolē'' "contraction") is the absence of ventricular contractions in the context of a lethal heart arrhythmia (in contrast to an induced asystole on a cooled patient on a heart-lun ...

, dizziness, and

sleepiness Somnolence (alternatively sleepiness or drowsiness) is a state of strong desire for sleep, or sleeping for unusually long periods (compare hypersomnia). It has distinct meanings and causes. It can refer to the usual state preceding falling asleep ...

. Abnormal heart rhythms and asystole are possible complications of hypermagnesemia related to the heart. Magnesium acts as a physiologic calcium blocker, which results in abnormalities of the

electrical conduction system of the heart The cardiac conduction system (CCS, also called the electrical conduction system of the heart) transmits the Cardiac action potential, signals generated by the sinoatrial node – the heart's Cardiac pacemaker, pacemaker, to cause the heart musc ...

. Consequences related to serum concentration: * 4.0 mEq/L – Decreased reflexes * >5.0 mEq/L – Prolonged atrioventricular conduction * >10.0 mEq/L –

Third-degree atrioventricular block Third-degree atrioventricular block (AV block) is a medical condition in which the electrical impulse generated in the sinoatrial node (SA node) in the atrium of the heart can not propagate to the ventricles. Because the impulse is blocked, an ...

(AV block) * >13.0 mEq/L –

Cardiac arrest Cardiac arrest (also known as sudden cardiac arrest CA is when the heart suddenly and unexpectedly stops beating. When the heart stops beating, blood cannot properly Circulatory system, circulate around the body and the blood flow to the ...

At magnesium levels about 4.5 mEq/L the

stretch reflex The stretch reflex (myotatic reflex), or more accurately ''muscle stretch reflex'', is a muscle contraction in response to stretching a muscle. The function of the reflex is generally thought to be maintaining the muscle at a constant length but ...

is lost and with over 6.5 mEq/L

respiratory failure Respiratory failure results from inadequate gas exchange by the respiratory system, meaning that the arterial oxygen, carbon dioxide, or both cannot be kept at normal levels. A drop in the oxygen carried in the blood is known as hypoxemia; a r ...

may be observed. On ECG hypermagnesemia is mainly manifested by prolongation of PR and QRS intervals,

T wave In electrocardiography, the T wave represents the repolarization of the ventricles. The interval from the beginning of the QRS complex to the apex of the T wave is referred to as the ''absolute refractory period''. The last half of the T wav ...

changes and AV block. The therapeutic range for the prevention of the pre-eclamptic uterine contractions is: 4.0–7.0 mEq/L. As per Lu and Nightingale, serum magnesium concentrations associated with maternal toxicity (also neonate depression, hypotonia and low

Apgar score The Apgar score is a quick way for health professionals to evaluate the health of all newborns at 1 and 5 minutes after birth and in response to resuscitation. It was originally developed in 1952 by an anesthesiologist at Columbia University, ...

s) are: * 7.0–10.0 mEq/L – Loss of

patellar reflex The patellar reflex, also called the knee reflex or knee-jerk, is a stretch reflex which tests the L2, L3, and L4 segments of the spinal cord. Many animals, most significantly humans, have been seen to have the patellar reflex, including dogs, cat ...

* 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

Complications

Severe hypermagnesemia (levels greater than 12 mg/dL) can lead to cardiovascular complications (hypotension and arrhythmias) and neurological disorder (confusion and lethargy). Higher values of serum magnesium (exceeding 15 mg/dL) can induce cardiac arrest and coma.

Causes

Magnesium status depends on three organs: uptake in the

intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. T ...

, storage in the

bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...

, and excretion in the

kidneys In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and right in the retro ...

. Hypermagnesemia is therefore often due to problems in these organs, mostly the intestine or kidney.

Predisposing conditions

Hemolysis Hemolysis or haemolysis (), also known by #Nomenclature, several other names, is the rupturing (lysis) of red blood cells (erythrocytes) and the release of their contents (cytoplasm) into surrounding fluid (e.g. blood plasma). Hemolysis may ...

, magnesium concentration in

red blood cell Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood cel ...

s is approximately three times greater than in serum, therefore hemolysis can increase plasma magnesium. Hypermagnesemia is expected only in massive hemolysis. *

Chronic kidney disease Chronic kidney disease (CKD) is a type of long-term kidney disease, defined by the sustained presence of abnormal kidney function and/or abnormal kidney structure. To meet criteria for CKD, the abnormalities must be present for at least three mo ...

, excretion of magnesium becomes impaired when

creatinine clearance Assessment of kidney function occurs in different ways, using the presence of symptoms and signs, as well as measurements using urine tests, blood tests, and medical imaging. Functions of a healthy kidney include maintaining a person's fluid ...

falls below 30 ml/min. However, hypermagnesemia is not a prominent feature of chronic kidney disease unless magnesium intake is increased. *

Magnesium toxicity Hypermagnesemia is an electrolyte disorder in which there is a high level of magnesium in the blood. Symptoms include weakness, confusion, respiratory depression, decreased breathing rate, and hyporeflexia, decreased reflexes. Hypermagnesemia can ...

from emergency pre-eclampsia treatment during labor and delivery. * Other conditions that can predispose to mild hypermagnesemia are

diabetic ketoacidosis Diabetic ketoacidosis (DKA) is a potentially life-threatening acute complication of diabetes mellitus. Signs and symptoms may include vomiting, abdominal pain, deep gasping breathing, increased urination, weakness, confusion and occasionally ...

adrenal insufficiency Adrenal insufficiency is a condition in which the adrenal glands do not produce adequate amounts of steroid hormones. The adrenal glands—also referred to as the adrenal cortex—normally secrete glucocorticoids (primarily cortisol), mineraloco ...

hypothyroidism Hypothyroidism is an endocrine disease in which the thyroid gland does not produce enough thyroid hormones. It can cause a number of symptoms, such as cold intolerance, poor ability to tolerate cold, fatigue, extreme fatigue, muscle aches, co ...

hyperparathyroidism Hyperparathyroidism is an increase in parathyroid hormone (PTH) levels in the blood. This occurs from a disorder either within the parathyroid glands ( primary hyperparathyroidism) or as response to external stimuli ( secondary hyperparathyroi ...

, and

lithium Lithium (from , , ) is a chemical element; it has chemical symbol, symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard temperature and pressure, standard conditions, it is the least dense metal and the ...

intoxication Intoxication — or poisoning, especially by an alcoholic or narcotic substance — may refer to: * Substance intoxication: ** Alcohol intoxication ** LSD intoxication ** Toxidrome ** Tobacco intoxication ** Cannabis intoxication ** Cocaine i ...

Metabolism

For a detailed description of magnesium

homeostasis In biology, homeostasis (British English, British also homoeostasis; ) is the state of steady internal physics, physical and chemistry, chemical conditions maintained by organism, living systems. This is the condition of optimal functioning fo ...

and

metabolism Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the co ...

see

hypomagnesemia Magnesium deficiency is an electrolyte disturbance in which there is a low level of magnesium in the body. Symptoms include tremor, poor coordination, muscle spasms, loss of appetite, personality changes, and nystagmus. Complications may in ...

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.

Treatment

People with normal

kidney function Assessment of kidney function occurs in different ways, using the presence of symptoms and medical sign, signs, as well as measurements using urine tests, blood tests, and medical imaging. Renal physiology, Functions of a healthy kidney include ...

(

glomerular filtration rate Renal functions include maintaining an acid–base balance; regulating fluid balance; regulating sodium, potassium, and other electrolytes; clearance (medicine), clearing toxins; absorption of glucose, amino acids, and other small molecules; reg ...

(GFR) over 60 ml/min) and mild asymptomatic hypermagnesemia require no treatment except for the removal of all sources of exogenous magnesium. One must consider that the half-time of elimination of magnesium is approximately 28 hours. In more severe cases, close monitoring of the ECG, blood pressure, and neuromuscular function and early treatment are necessary: Intravenous

calcium gluconate Calcium gluconate is the calcium salt of gluconic acid and is used as a mineral supplement and medication. As a medication it is used by injection into a vein to treat low blood calcium, high blood potassium, and magnesium toxicity. Supplem ...

since the actions of magnesium in neuromuscular and cardiac function become antagonized by calcium. Severe clinical conditions require increasing renal magnesium excretion through: Intravenous

loop diuretic Loop diuretics are pharmacological agents that primarily inhibit the Na-K-Cl cotransporter located on the luminal membrane of cells along the thick ascending limb of the loop of Henle. They are often used for the treatment of hypertension and e ...

s (e.g.,

), or

, when kidney function is impaired, or the patient is symptomatic from severe hypermagnesemia. This approach usually removes magnesium efficiently (up to 50% reduction after a 3- to 4-hour treatment). Dialysis can, however, increase the excretion of calcium by developing

hypocalcemia Hypocalcemia is a medical condition characterized by low calcium levels in the blood serum. The normal range of blood calcium is typically between 2.1–2.6 mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L), while levels less than 2.1 ...

, thus possibly worsening the symptoms and signs of hypermagnesemia. The use of diuretics must be associated with infusions of saline solutions to avoid further

electrolyte disturbances An electrolyte is a substance that conducts electricity through the movement of ions, but not through the movement of electrons. This includes most soluble salts, acids, and bases, dissolved in a polar solvent like water. Upon dissolving, the ...

(e.g.,

hypokalemia Hypokalemia is a low level of potassium (K+) in the blood serum. Mild low potassium does not typically cause symptoms. Symptoms may include feeling tired, leg cramps, weakness, and constipation. Low potassium also increases the risk of an a ...

) and

metabolic alkalosis Metabolic alkalosis is an acid-base disorder in which the pH of tissue is elevated beyond the normal range (7.35–7.45). This is the result of decreased hydrogen ion concentration, leading to increased bicarbonate (), or alternatively a dire ...

. The clinician must perform serial measurements of calcium and magnesium. In association with electrolytic correction, it is often necessary to support cardiorespiratory activity. As a consequence, the treatment of this electrolyte disorder can frequently require intensive care unit (ICU) admission. Particular clinical conditions require a specific approach. For instance, during the management of

eclampsia Eclampsia is the onset of seizures (convulsions) in a pregnant woman with pre-eclampsia. Pre-eclampsia is a hypertensive disorder of pregnancy that presents with three main features: new onset of high blood pressure, large amounts of proteinuria ...

, the magnesium infusion is stopped if urine output drops to less than 80 mL (in 4 hours), deep tendon reflexes are absent, or the respiratory rate is below 12 breaths/minute. A 10% calcium gluconate or chloride solution can serve as an antidote.

Prognosis

The prognosis of hypermagnesemia depends on magnesium values and on the clinical condition that induced hypermagnesemia. Values that are not excessively high (mild hypermagnesemia) and in the absence of triggering and aggravating conditions (e.g., chronic kidney disease) are benign conditions. On the contrary, high values (severe hypermagnesemia) expose the patient to high risks and high mortality.

Epidemiology

Hypermagnesemia is an uncommon electrolyte disorder. It occurs in approximately 10 to 15% of hospitalized patients with renal failure. Furthermore, epidemiological data suggest that there is a significant prevalence of high levels of serum magnesium in selected healthy populations. For instance the overall prevalence of hypermagnesemia was 3.0%, especially in males in Iran. High magnesium concentrations were typical in people with cardiovascular disease, and 2.3 mg/dL or higher values were associated with worse hospital mortality.

References

External links

{{Mineral metabolic pathology Electrolyte disturbances Magnesium Nephrology Toxic effects of metals Wikipedia medicine articles ready to translate