Initial Approach to Treating Primary Hyperparathyroidism Symptoms
Surgical excision of abnormal parathyroid tissue is the only definitive cure for primary hyperparathyroidism and should be performed in patients with symptomatic disease, including kidney stones, bone pain, fractures, neuromuscular symptoms, or osteoporosis. 1, 2
Confirming the Diagnosis Before Treatment
Before initiating any treatment, confirm the diagnosis biochemically by measuring serum calcium (corrected for albumin) and intact PTH simultaneously 1. Hypercalcemia with normal or elevated iPTH confirms primary hyperparathyroidism 3, 4.
Critical diagnostic step: Measure 25-OH Vitamin D levels to exclude hypovitaminosis D as a concomitant secondary cause of hyperparathyroidism, as vitamin D deficiency can complicate PTH interpretation 3, 2. Aim for 25-OH vitamin D levels >20 ng/ml (50 mmol/l) 2.
Surgical Management: The Definitive Treatment
Indications for Surgery
Surgery is recommended for patients meeting any of these criteria 1:
- Symptomatic disease: kidney stones, bone pain, fractures, neuromuscular symptoms
- Impaired kidney function: GFR < 60 mL/min/1.73 m²
- Osteoporosis on DEXA scan
- Hypercalciuria
Surgical Approaches
Two effective surgical options exist 5, 1:
Minimally invasive parathyroidectomy (MIP) offers shorter operating times, faster recovery, and decreased perioperative costs compared to bilateral neck exploration 5, 1. MIP requires confident preoperative localization of a single parathyroid adenoma and intraoperative PTH monitoring 5.
Bilateral neck exploration (BNE) remains necessary for cases with discordant/nonlocalizing imaging or suspected multigland disease 5.
Preoperative Imaging
Obtain ultrasound and/or dual-phase 99mTc-sestamibi scintigraphy with SPECT/CT before surgery, as the combination is highly sensitive for localizing parathyroid adenomas 3, 2.
Postoperative Monitoring
Monitor ionized calcium every 4-6 hours for the first 48-72 hours after surgery, then twice daily until stable 5, 2. Initiate calcium gluconate infusion and adjust phosphate binders as needed based on serum phosphorus levels 5, 2.
Medical Management: For Patients Unable to Undergo Surgery
Cinacalcet (Calcimimetic)
For patients with primary hyperparathyroidism who cannot undergo parathyroidectomy, cinacalcet is FDA-approved for treatment of hypercalcemia 6.
Dosing: Start cinacalcet at 30 mg twice daily orally with food 6. Titrate every 2 to 4 weeks through sequential doses of 30 mg twice daily, 60 mg twice daily, 90 mg twice daily, and 90 mg 3 or 4 times daily as necessary to normalize serum calcium levels 6.
Monitoring: Measure serum calcium within 1 week after initiation or dose adjustment 6. Once maintenance dose is established, measure serum calcium every 2 months 6.
Critical Safety Considerations with Cinacalcet
Do not initiate cinacalcet if serum calcium is below the lower limit of normal 6. Cinacalcet lowers serum calcium and can cause hypocalcemia, leading to paresthesias, myalgias, muscle spasms, tetany, seizures, QT interval prolongation, and ventricular arrhythmia 6. Life-threatening events and fatal outcomes associated with hypocalcemia have been reported 6.
Patients with congenital long QT syndrome, history of QT interval prolongation, family history of long QT syndrome or sudden cardiac death are at increased risk for QT interval prolongation and ventricular arrhythmias if they develop hypocalcemia 6.
Supportive Measures
Ensure adequate dietary calcium intake through dietary evaluation 2. Maintain adequate hydration to prevent complications 7.
Common Pitfalls to Avoid
Do not delay surgical intervention in symptomatic patients or those with complications like recurrent renal stones, as this can lead to progressive renal damage 2.
Do not use cinacalcet in patients who are surgical candidates, as surgery is curative while medical therapy only manages symptoms 1, 2, 8.
Do not forget to check vitamin D status before attributing elevated PTH solely to primary hyperparathyroidism, as vitamin D deficiency is a common confounder 3, 1, 2.