Hypermagnesemia is an electrolyte imbalance with an elevated level of magnesium in the blood. Magnesium is a mineral the body uses for many functions, including bone health and cardiovascular function. While most magnesium is stored in bones and muscles, a small amount circulates in the bloodstream. The body’s kidney and gastrointestinal systems regulate these levels, absorbing what is needed and excreting the rest. This condition is uncommon because healthy kidneys are efficient at filtering out excess magnesium.
Causes of High Magnesium
The most common cause of hypermagnesemia is kidney failure. When kidney function is impaired, they cannot effectively remove surplus magnesium from the blood. This inability to excrete the mineral makes individuals with acute or chronic kidney disease more susceptible to its accumulation.
Another cause is the excessive intake of magnesium, usually from sources other than food, as it is rare for this condition to develop from diet alone. The risk rises with the use of magnesium-containing supplements or over-the-counter medications. Certain laxatives and some antacids contain high amounts of magnesium. When a person, particularly someone with underlying kidney issues, consumes these products in large quantities, their system can become overwhelmed.
Certain medical conditions and treatments can also contribute to elevated magnesium levels. Endocrine disorders such as hypothyroidism and adrenal insufficiency (Addison’s disease) are recognized causes. The use of lithium-based medications can lead to hypermagnesemia by reducing the kidneys’ ability to excrete the mineral. Less frequently, conditions like milk-alkali syndrome can make a person more susceptible.
Recognizing the Symptoms
The signs of hypermagnesemia often progress in severity as magnesium levels rise. In mild cases, an individual might not notice any symptoms. When symptoms do appear, they are often subtle and can include nausea, vomiting, headache, and a feeling of warmth or flushing in the face. General muscle weakness and dizziness are also common early indicators.
As the concentration of magnesium increases to a moderate level, symptoms become more pronounced and affect the nervous and cardiovascular systems. An individual may experience significant drowsiness, confusion, and a decrease in their deep tendon reflexes. Other effects include hypotension (low blood pressure) and bradycardia (a slower-than-normal heart rate). Some people may also experience blurred vision or constipation.
Severe hypermagnesemia, where blood levels exceed 12 mg/dL, is a life-threatening emergency. The high concentration of magnesium can lead to muscle paralysis and respiratory depression, making it difficult to breathe. The impact on the heart can become more severe, leading to a complete heart block or cardiac arrest. In the most extreme cases, the condition can progress to a coma.
Medical Diagnosis and Treatment
Diagnosing hypermagnesemia is a straightforward process involving a blood test to measure the concentration of magnesium. A normal level is between 1.7 and 2.3 mg/dL, while a level of 2.6 mg/dL or higher indicates hypermagnesemia. To understand the cause, a doctor will review the patient’s medical history, paying close attention to kidney health, diet, and the use of any medications or supplements.
Treatment strategies are tailored to the severity of the condition. For mild cases in individuals with healthy kidneys, the first step is to identify and eliminate the source of excess magnesium. This involves discontinuing any magnesium-containing supplements, laxatives, or antacids. Once the intake stops, healthy kidneys can usually excrete the excess mineral.
For more moderate to severe cases, hospital-based treatment is necessary. This often includes intravenous (IV) fluids to help dilute the magnesium and enhance its excretion by the kidneys. Doctors may also administer IV calcium gluconate. Calcium directly counteracts the effects of high magnesium on the heart and muscles, helping to stabilize heart rhythm and improve breathing.
In the most severe instances, particularly when a patient has significant kidney failure, dialysis may be required. Hemodialysis is an effective method for removing excess magnesium from the blood when the kidneys are unable to do so. This procedure can reduce magnesium levels by as much as 50% after a single session, making it a useful intervention in critical situations.