From the Guidelines
Damaged kidneys can indeed lead to hypercalcemia, as evidenced by the complex interplay of mineral and bone disorders in chronic kidney disease (CKD) 1. When kidneys are damaged, they may fail to properly excrete excess calcium and phosphate, disrupting the body's calcium balance. Additionally, damaged kidneys produce less active vitamin D (calcitriol), which normally helps regulate calcium levels.
Key Factors Contributing to Hypercalcemia in CKD
- Impaired excretion of excess calcium and phosphate
- Reduced production of active vitamin D (calcitriol)
- Development of secondary hyperparathyroidism, with excess parathyroid hormone (PTH) pulling calcium from bones into the bloodstream
- Decreased ability to filter and remove excess calcium from the blood
Management and Treatment
Management of hypercalcemia in CKD typically involves treating the underlying kidney disease, maintaining proper hydration, and possibly using medications like bisphosphonates or calcimimetics to lower calcium levels 1. It is also crucial to carefully monitor electrolyte balance and adjust dietary calcium and vitamin D intake under medical supervision.
Important Considerations
- Avoiding inappropriate calcium loading in adults with CKD is recommended, as hypercalcemia may be harmful in all GFR categories of CKD 1
- Treatment approaches for CKD-mineral and bone disorder (CKD-MBD) should be based on serial assessments of biochemical variables, including serum phosphate, calcium, and PTH 1
From the Research
Damaged Kidneys and Hypercalcemia
- Damaged kidneys can lead to hypercalcemia, as evidenced by a study that found hypercalcemia can result from excessive bone resorption, renal calcium retention, excessive intestinal calcium absorption, or a combination of these conditions 2.
- Hypercalcemia may also provoke acute renal failure (ARF) or hypertension, or aggravate the tubular necrosis that is frequently found in cases of ARF 2.
- A case series of two patients with hypercalcemia and acute kidney injury (AKI) found that excess exogenous intake of calcium compounds and vitamin D supplements can have deleterious effects on renal function 3.
Causes of Hypercalcemia
- Primary hyperparathyroidism (PHPT) and malignancy are the most common causes of hypercalcemia, accounting for approximately 90% of cases 4.
- Other causes of hypercalcemia include granulomatous disease, endocrinopathies, immobilization, genetic disorders, and medications such as thiazide diuretics and supplements like calcium, vitamin D, or vitamin A 4.
- Thiazide diuretics can cause severe hypercalcemia, and patients on these medications should have their electrolytes frequently checked, especially if they are taking calcium supplements 5.
Treatment of Hypercalcemia
- Treatment of hypercalcemia usually involves hydration and intravenous bisphosphonates, such as zoledronic acid or pamidronate 4.
- In patients with kidney failure, denosumab and dialysis may be indicated 4.
- Glucocorticoids may be used as primary treatment when hypercalcemia is due to excessive intestinal calcium absorption (vitamin D intoxication, granulomatous disorders, some lymphomas) 4.