Nursing Care Plan | NCP Hypermagnesemia

Hypermagnesemia occurs when the serum magnesium concentration is greater than 2.7 mg/dL (2.3 mEq/L), but signs and symptoms do not occur until the magnesium reaches 4 mg/dL. The normal serum magnesium level is 1.7 to 2.7 mg/dL (1.4 to 2.3 mEq/L). Magnesium is found in the bones: 1% is located in the extracellular compartment, and the remainder is found within the cells.

Magnesium plays an important role in neuromuscular function. It also has a role in several enzyme systems, particularly the metabolism of carbohydrates and proteins, as well as maintenance of normal ionic balance (it triggers the sodium-potassium pump), osmotic pressure, myocardial functioning, and bone metabolism. Because the kidneys are able to excrete large amounts of magnesium ( 5000 mg/day), either the patient has to ingest extraordinary amounts of magnesium or the glomerular filtration of the kidneys needs to be very depressed for the patient to develop hypermagnesemia. Complications include complete heart block, cardiac arrest, and respiratory paralysis.

Hypermagnesemia, although rare, usually occurs in patients with chronic renal disease who consume excessive quantities of magnesium, commonly in the form of magnesium-containing laxatives or antacids. Obstetric patients who are treated with parenteral magnesium for preeclampsia or patients with acute adrenocortical insufficiency (Addison’s disease) may also develop hypermagnesemia. Both hypothermia and shock can also lead to a high serum magnesium level.

Nursing care plan assessment and physical examination
The patient’s chief complaint may be muscle weakness and fatigue. Precipitating factors may include renal failure, laxative or antacid abuse, adrenal insufficiency, diabetes, or acidosis. Medication history may include magnesium-containing laxatives such as milk of magnesia, antacids that contain magnesium hydroxide, or parenteral administration of magnesium sulfate. Ask the patient to describe any symptoms, which may range from none to full cardiopulmonary arrest. The patient may experience nausea and vomiting, flushed skin, or diaphoresis; changes in the cardiac rhythm lead to palpitations or dizziness, depression, lethargy, thirst, muscle weakness, or even paralysis.

Generally, patients do not develop signs and symptoms until the serum magnesium reaches more than 4 mEq/L. Assess the vital signs, which may show tachycardia, bradycardia, or hypotension. The patient may be disoriented, confused, or even unresponsive. When strength and movement are assessed, you may find the patient has lost deep tendon reflexes, has muscle weakness, and may even have some paralysis. Cardiopulmonary arrest may occur when the respiratory muscles are paralyzed as a result of a magnesium level in excess of 10 mEq/L or as a consequence of depressed myocardial contractility.

The patient with hypermagnesemia usually has chronic renal failure. Assess the patient’s ability to cope with a chronic disease, as well as an acute complication. The patient may have had to cope with a change in lifestyle and roles that may be compromised by the sudden and potentially life-threatening complication of hypermagnesemia. The patient’s degree of anxiety about the illness should also be assessed.

Nursing care plan primary nursing diagnosis: Risk for injury related to neurosensory alterations secondary to hypermagnesemia.

Nursing care plan intervention and treatment plan
The physician discontinues all medications that contain magnesium. The patient may be given calcium gluconate in emergencies to antagonize the effects of magnesium. If the patient does not have severe renal failure, 1000 mL of 0.9% saline with 2 g of calcium gluconate may be infused to increase magnesium excretion at a rate of 150 to 200 mL per hour. In patients with inadequate renal function, the physician may prescribe dialysis with magnesium-free dialysate. Prompt supportive therapy is essential, such as mechanical ventilation if the patient has respiratory failure or a temporary pacemaker if the patient has symptomatic bradycardia.

During treatment, monitor the serum magnesium in patients at risk for hypermagnesemia. Monitor vital signs, urine output, and the neuromuscular status, including level of consciousness, orientation, and muscle strength and function. Assess the patellar (knee-jerk) reflex in patients with a magnesium level above 5 mEq/L:With the patient lying flat or sitting on the side of the bed, support the knee and tap the patellar tendon firmly just below the patella. A normal response is extension of the knee. An absent reflex may indicate a magnesium level greater than
7 mEq/L and should be reported to the physician.

Maintain the patient’s airway, breathing, and circulation until the magnesium levels return to normal. Have emergency airway equipment and a manual resuscitator bag at the patient’s bedside at all times. Keep a working endotracheal suction present. Maintain patient safety measures. Reassure the patient and significant others that the patient’s neuromuscular status will return to baseline with treatment.

Educate the patient with chronic renal failure to review all over-the-counter medications with the physician and pharmacist before use. These medications include vitamin supplements that contain minerals because these usually contain magnesium. Provide a list of common magnesiumcontaining medications that the patient should avoid.

Nursing care plan discharge and home health care guidelines
To prevent a recurrence of hypermagnesemia, teach the patient to avoid sources of magnesium such as laxatives, antacids, and vitamin-mineral supplements and to consult with the pharmacist or physician before using any over-the-counter medications. The patient should also be taught the signs and symptoms of hypermagnesemia (changes in level of consciousness, neuromuscular weakness, nausea and vomiting) and instructed to notify the physician if these return.

If the patient suffered from prolonged neuromuscular symptoms, he or she may have developed muscle weakness as a result of disease. Teach safety measures to the patient and significant others, including the use of any assistive devices (cane or walker) and seeking assistance when ambulating. The patient should also be taught muscle-strengthening exercises and may need a home care evaluation before being discharged.