From the Guidelines
Elevated phosphorus levels are most commonly caused by decreased kidney function, as the kidneys are primarily responsible for phosphorus excretion, and high phosphate intake, which can promote secondary hyperparathyroidism (SHPT) 1.
Causes of Elevated Phosphorus
- Decreased kidney function, such as chronic kidney disease (CKD) and acute kidney injury, as the kidneys play a crucial role in phosphorus excretion
- Excessive intake of phosphorus through diet or supplements, particularly phosphate-containing laxatives, enemas, or vitamin D supplements
- Certain medical conditions, including:
- Hypoparathyroidism (low parathyroid hormone)
- Tumor lysis syndrome (rapid breakdown of cancer cells)
- Rhabdomyolysis (muscle tissue breakdown)
- Diabetic ketoacidosis
- Medications like bisphosphonates used for osteoporosis treatment, which can temporarily increase phosphorus levels
- Laboratory errors or sample hemolysis, leading to pseudohyperphosphatemia
Importance of Addressing Elevated Phosphorus
It is essential to identify and address the underlying cause of elevated phosphorus levels, as chronically elevated levels can lead to calcium-phosphate deposits in blood vessels and tissues, increasing cardiovascular risk 1.
Treatment Approaches
Treatment may include:
- Dietary phosphorus restriction
- Phosphate binders with meals
- Treating the primary condition
- In severe cases, dialysis for those with kidney failure The 2017 KDIGO CKD-MBD Guideline update emphasizes the importance of addressing modifiable risk factors, including high phosphate intake, to prevent SHPT and related complications 1.
From the Research
Causes of Elevation in Phosphorus
- Impaired glomerular filtration in chronic kidney disease (CKD) can cause a hyperphosphatemic state 2, 3
- Inability of the kidneys to generate active vitamin D, leading to low calcium levels and high phosphate levels 2
- High parathyroid hormone (PTH) levels, which increase the rate of bone turnover and release of calcium and phosphate into the blood 4
- Dietary intake of high amounts of phosphorus, which can exacerbate hyperphosphatemia in patients with CKD 2, 3
Related Conditions
- Secondary hyperparathyroidism (2 degrees HPT), which can develop in response to high phosphate, low calcium, and low 1,25-dihydroxyvitamin D(3) levels 4
- Vascular calcification and coronary artery disease, which can result from high PTH levels and hyperphosphatemia 4, 5
- Renal osteodystrophy, which can occur due to the body's compensation mechanisms for hyperphosphatemia 2, 3