From the Guidelines
Elevated calcium and vitamin D can cause hypercalcemia, a condition that poses a significant risk to morbidity and mortality in patients with chronic kidney disease (CKD). This occurs when vitamin D levels are too high, leading to increased calcium absorption from the intestines, which can increase the Ca-P product index in blood and worsen kidney disease 1. Symptoms of hypercalcemia include kidney stones, bone pain, excessive urination, fatigue, weakness, digestive issues, and in severe cases, confusion and cardiac arrhythmias.
Causes and Risks
The relationship between serum calcium levels and morbidity in CKD patients is complex, and some studies suggest that transient mild hypercalcemia may not have detrimental effects on morbidity 1. However, severe hypercalcemia with clinical symptoms must be treated appropriately to prevent serious complications. The risk of hypercalcemia is increased in CKD patients due to decreased calcium excretion and increased calcium absorption from the intestines.
Treatment and Prevention
Treatment of hypercalcemia involves discontinuing vitamin D supplements, reducing calcium intake, increasing fluid intake, and in severe cases, medications like bisphosphonates or calcitonin to lower calcium levels 1. Underlying causes such as hyperparathyroidism, certain cancers, or granulomatous diseases should be investigated. Normal vitamin D levels should be maintained between 30-50 ng/mL, and calcium intake should generally not exceed 1,000-1,200 mg daily for adults. If you experience symptoms of hypercalcemia, seek medical attention promptly as untreated hypercalcemia can lead to serious complications including kidney damage and cardiac arrest.
Key Considerations
- Net calcium absorption is reduced in chronic renal failure as a consequence of both decreased calcium intake and decreased fraction of calcium absorbed by the intestine 1.
- Dietary calcium intake is low in patients with CKD, and intake of calcium in adults with advanced CKD ranged between 300 and 700 mg/day 1.
- There are no data suggesting that transient mild hypercalcemia has detrimental effects on morbidity in patients with CKD, but severe hypercalcemia poses a significant risk to morbidity and mortality 1.
From the FDA Drug Label
5.2 Hypocalcemia 2.5 Recommendations for Calcium and Vitamin D Supplementation
Elevated calcium and vitamin D can cause hypercalcemia.
- The use of calcitonin may be affected by calcium and vitamin D supplementation.
- Hypocalcemia is a precaution, but elevated calcium levels are associated with hypercalcemia. 2
From the Research
Causes of Elevated Calcium and Vitamin D
- Elevated calcium and vitamin D can cause hypercalcemia, a condition characterized by high levels of calcium in the blood 3, 4, 5, 6, 7.
- Hypercalcemia can be caused by various factors, including primary hyperparathyroidism, malignancies, granulomatous disease, and excessive intake of calcium and vitamin D supplements 4, 6, 7.
- Vitamin D-mediated hypercalcemia can occur due to the ingestion of excessive amounts of vitamin D, ectopic production of 1,25-dihydroxyvitamin D, and impaired degradation of 1,25-dihydroxyvitamin D 7.
Symptoms and Diagnosis
- Hypercalcemia can be asymptomatic or symptomatic, with symptoms ranging from mild to severe, including fatigue, constipation, nausea, vomiting, dehydration, confusion, and coma 4, 6.
- The diagnosis of hypercalcemia is based on serum calcium levels, and the underlying cause is identified through various tests, including serum intact parathyroid hormone (PTH) levels 6.
- Serum PTH levels can distinguish between PTH-dependent and PTH-independent causes of hypercalcemia 6.
Treatment
- The treatment of hypercalcemia depends on the underlying cause and severity of the condition 3, 4, 5, 6.
- Mild hypercalcemia may not require acute intervention, while severe hypercalcemia requires immediate treatment with hydration, intravenous bisphosphonates, and other medications 6.
- Glucocorticoids may be used as primary treatment for hypercalcemia caused by excessive intestinal calcium absorption, such as vitamin D intoxication 5, 6, 7.