From the Guidelines
This 71-year-old female patient with a PTH level of 69 ng/L and calcium level of 2.14 mmol/L should be considered for parathyroidectomy due to the potential risks of primary hyperparathyroidism, including osteoporosis and kidney stone formation, as indicated by the American Association of Endocrine Surgeons guideline 1. The patient's elevated PTH and calcium levels are consistent with primary hyperparathyroidism (PHPT), which is commonly caused by hyperplasia or an adenoma in one or more parathyroid glands.
- Key considerations in managing this patient include:
- Evaluating for symptoms or complications such as osteoporosis, kidney stones, or neurocognitive issues
- Maintaining adequate hydration and avoiding calcium supplements
- Ensuring appropriate vitamin D levels (target 75-100 nmol/L)
- Regular monitoring of calcium, PTH, kidney function, and bone density
- The decision to proceed with parathyroidectomy should be based on the presence of symptoms, complications, or significant elevations in calcium levels, rather than the PTH concentration itself, as stated in the American Association of Endocrine Surgeons guideline 1.
- Medical management with cinacalcet may be considered for symptomatic hypercalcemia if surgery is not indicated or the patient declines, although this is not the preferred treatment for PHPT.
- It is essential to note that even mild elevations in PTH and calcium can cause long-term complications, including bone loss, nephrolithiasis, and cardiovascular effects, emphasizing the importance of evaluation and potential intervention despite the modest laboratory abnormalities, as discussed in the context of PHPT diagnosis and management 1.
From the FDA Drug Label
Approximately 60% of patients with mild (iPTH ≥ 300 to ≤ 500 pg/mL), 41% with moderate (iPTH > 500 to 800 pg/mL), and 11% with severe (iPTH > 800 pg/mL) secondary HPT achieved a mean iPTH value of ≤ 250 pg/mL.
The patient's PTH level is 69 ng/L, which is approximately 690 pg/mL. This is considered severe secondary hyperparathyroidism.
- Cinacalcet efficacy: The FDA drug label reports that only 11% of patients with severe secondary HPT achieved a mean iPTH value of ≤ 250 pg/mL 2.
- Dose and administration: The label does not provide specific dosing recommendations for patients with PTH levels as high as 690 pg/mL.
- Calcium levels: The patient's calcium level is 2.14 mmol/L, which is within the normal range.
- Monitoring: The label recommends monitoring serum calcium and phosphorus levels during treatment with cinacalcet. The patient's calcium and PTH levels should be closely monitored while on cinacalcet, and the dose adjusted accordingly to avoid hypocalcemia 2.
From the Research
Patient Profile
- 71-year-old female (YOF) with primary hyperparathyroidism (PHPT)
- Parathyroid hormone (PTH) level: 69 ng/L
- Calcium level: 2.14 mmol/L
Treatment Options
- Cinacalcet: a calcimimetic agent that increases the sensitivity of parathyroid calcium-sensing receptors to extracellular calcium, thereby reducing serum calcium levels 3, 4, 5, 6, 7
- Cinacalcet has been shown to decrease serum calcium and PTH levels in patients with PHPT, although its effect on bone mineral density is uncertain 4, 5, 6
Efficacy of Cinacalcet
- Studies have demonstrated that cinacalcet can normalize serum calcium levels in most patients with PHPT, while modestly reducing PTH levels 3, 6, 7
- Cinacalcet has been shown to be effective in reducing serum calcium concentrations in PHPT patients with hypercalcaemia, including those awaiting parathyroidectomy 7
Safety and Adverse Events
- Common adverse events associated with cinacalcet include gastrointestinal symptoms such as nausea and appetite loss, as well as severe dehydration due to hypercalcemia, myalgia, hypocalcemia, and increased urinary calcium excretion 6, 7
- Cinacalcet is usually well tolerated, but may require monitoring of bone mineral density and urinary calcium excretion 5, 6