From the Guidelines
Hypocalcemia, hypomagnesemia, and hypokalemia are common electrolyte disturbances that require systematic evaluation, with the most recent evidence suggesting that prevention of electrolyte disorders during kidney replacement therapy (KRT) is crucial, as stated in the 2024 study 1. When evaluating these electrolyte disturbances, it is essential to consider the interconnectedness of calcium, magnesium, and potassium.
Causes of Hypocalcemia
For hypocalcemia workup, measure serum calcium (both total and ionized), albumin, phosphorus, magnesium, parathyroid hormone (PTH), and vitamin D levels.
- Common causes include:
- Vitamin D deficiency
- Hypoparathyroidism
- Chronic kidney disease
- Pancreatitis
- Medication effects (bisphosphonates, anticonvulsants)
Causes of Hypomagnesemia
For hypomagnesemia, check serum magnesium, urinary magnesium excretion, and evaluate for:
- Gastrointestinal losses (diarrhea, malabsorption)
- Renal losses (diuretics, certain antibiotics like aminoglycosides)
- Alcoholism
- Poor nutrition
Causes of Hypokalemia
For hypokalemia, measure serum potassium, assess acid-base status with blood gases, check urinary potassium excretion, and evaluate blood pressure.
- Common causes include:
- Gastrointestinal losses (vomiting, diarrhea)
- Renal losses (diuretics, hyperaldosteronism)
- Transcellular shifts (insulin, beta-agonists)
- Poor intake As noted in the 2017 study 1, hypokalemia is often the result of diuresis, but it may also result from the administration of potassium-free intravenous fluids, potassium loss from vomiting and diarrhea, and other endocrine and renal mechanisms. The use of dialysis solutions containing potassium, phosphate, and magnesium can help prevent electrolyte disorders during KRT, as recommended in the 2024 study 1. Medication effects should always be considered, as many drugs, including diuretics, proton pump inhibitors, and certain antibiotics, can cause multiple electrolyte abnormalities simultaneously, as highlighted in the 2018 study 1. Treatment should address the underlying cause while carefully replacing deficient electrolytes.
From the FDA Drug Label
As a nutritional adjunct in hyperalimentation, the precise mechanism of action for magnesium is uncertain. Early symptoms of hypomagnesemia (less than 1. 5 mEq/L) may develop as early as three to four days or within weeks. Predominant deficiency effects are neurological, e.g., muscle irritability, clonic twitching and tremors. Hypocalcemia and hypokalemia often follow low serum levels of magnesium.
The causes of hypocalcemia, hypomagnesemia, and hypokalemia can be related, as hypomagnesemia can lead to hypocalcemia and hypokalemia. Key points to consider in the workup include:
- Neurological symptoms: muscle irritability, clonic twitching, and tremors
- Electrolyte levels: magnesium, calcium, and potassium
- Timing of symptoms: can develop as early as three to four days or within weeks of magnesium deficiency 2 The workup should focus on identifying and addressing the underlying cause of hypomagnesemia, which can in turn help manage hypocalcemia and hypokalemia.
From the Research
Causes of Hypocalcemia
- Hypoparathyroidism, characterized by impaired secretion of parathyroid hormone (PTH), is a classic cause of chronic hypocalcemia 3
- Disorders that disrupt the metabolism of vitamin D can also lead to chronic hypocalcemia, as vitamin D is responsible for increasing the gut absorption of dietary calcium 3
- Postsurgical hypoparathyroidism is the most frequent cause of hypocalcemia 4
Causes of Hypomagnesemia and Hypokalemia
- Certain chemotherapies, including cisplatin, cetuximab, eribulin, and ifosfamide, can cause hypomagnesemia and hypokalemia as side effects 5
- Alcoholism and cisplatin administration are common causes of the syndrome of hypomagnesemic hypokalemia and hypocalcemia 6
- Medications that cause hypomagnesemia or hypokalemia can amplify electrolyte imbalances when used concurrently with chemotherapy 5
Workup for Hypocalcemia, Hypomagnesemia, and Hypokalemia
- Measurement of ionized calcium is the preferred way to ascertain the diagnosis of hypocalcemia and hypercalcemia 7
- Serum calcium level <8 mg/dl; 2.12 mmol/L is considered hypocalcemia 4
- Diagnosis of hypocalcemia can be divided into parathyroid hormone (PTH) and non-PTH mediated causes 4
- A comprehensive search for other causes is needed for appropriate treatment in non-PTH mediated forms of hypocalcemia 4
Treatment and Management
- Intravenous calcium infusion is essential to raise calcium levels and resolve or minimize symptoms in the setting of acute hypocalcemia 4
- Oral calcium and/or vitamin D supplementation is the most frequently used treatment for chronic hypocalcemia 4
- Providing the missing hormone with the use of the recombinant human (rh) PTH(1-84) has been recently approved for the treatment of hypoparathyroidism 4
- Oral and IV formulations of potassium and magnesium are options for treatment of symptomatic cases of electrolyte deficiency 5