What is the treatment approach for primary hyperparathyroidism (PHPT)?

Treatment Approach for Primary Hyperparathyroidism (PHPT)

Surgical parathyroidectomy is the only curative treatment for primary hyperparathyroidism and should be recommended for all symptomatic patients and those with asymptomatic disease who meet specific criteria for intervention. 1

Diagnosis and Evaluation

Primary hyperparathyroidism is defined by hypercalcemia with elevated or inappropriately normal PTH levels. Diagnosis is made through biochemical testing, specifically:

• Serum calcium measurement
• Parathyroid hormone (PTH) level
• No imaging is required for diagnosis, only for localization prior to surgery 1

Indications for Surgery

Parathyroidectomy is indicated in:

1. Symptomatic patients with:

   • Bone manifestations (osteoporosis, fractures)
   • Kidney stones or nephrocalcinosis
   • Neurocognitive disorders
   • Muscle weakness 1

2. Asymptomatic patients with any of the following:

   • Age ≤50 years
   • Serum calcium >0.25 mmol/L (1 mg/dL) above upper limit of normal
   • Osteoporosis (T-score ≤-2.5 at any site)
   • Impaired kidney function (GFR <60 mL/min/1.73m²)
   • Kidney stones or nephrocalcinosis
   • Hypercalciuria 1

Surgical Approaches

Two main surgical approaches are available:

1. Minimally Invasive Parathyroidectomy (MIP):

   • Unilateral operation with limited dissection
   • Requires confident preoperative localization of a single adenoma
   • Benefits: shorter operating times, faster recovery, decreased costs
   • Intraoperative PTH monitoring confirms removal of hyperfunctioning gland 1

2. Bilateral Neck Exploration (BNE):

   • Traditional approach where all parathyroid glands are identified
   • Necessary when:
     • Preoperative imaging is discordant or non-localizing
     • High suspicion for multigland disease
     • Reoperation cases 1

Preoperative Imaging

Imaging is essential for surgical planning, not for diagnosis:

• First-line: 99mTc-Sestamibi scan and/or ultrasound
• Second-line: CT scan, MRI
• Imaging is particularly crucial for reoperative cases 1

Postoperative Management

After parathyroidectomy:

1. Monitor calcium levels:

   • Check ionized calcium every 4-6 hours for first 48-72 hours
   • Then twice daily until stable 1

2. Manage hypocalcemia:

   • If ionized calcium falls below normal (<0.9 mmol/L):
     • Initiate calcium gluconate infusion at 1-2 mg elemental calcium/kg/hour
     • Adjust to maintain normal ionized calcium (1.15-1.36 mmol/L) 1

3. Transition to oral supplements:

   • Calcium carbonate 1-2g three times daily
   • Calcitriol up to 2μg/day
   • Adjust to maintain normal calcium levels 1

Medical Management

For patients who cannot undergo surgery:

• Bisphosphonates: Improve bone mineral density
• Calcimimetics (cinacalcet): Reduce serum calcium levels
• Monitoring: Regular follow-up of calcium, PTH, bone density, and renal function 2

Special Considerations

1. Multigland disease (15-20% of cases):

   • More common in familial forms (MEN1, MEN2A)
   • Requires bilateral exploration 1

2. Persistent or recurrent hyperparathyroidism:

   • Defined as hypercalcemia within 6 months (persistent) or after 6 months (recurrent) following surgery
   • Requires comprehensive imaging before reoperation 1

3. Normocalcemic PHPT:

   • Normal calcium with elevated PTH
   • Requires exclusion of secondary causes of hyperparathyroidism
   • Surgical criteria less well-defined 3

Pitfalls to Avoid

1. Relying on imaging for diagnosis: Imaging is for localization only, not diagnosis 1

2. Inadequate preoperative localization: Failed localization leads to more invasive surgery and higher complication rates 1

3. Incomplete monitoring post-surgery: Missing hypocalcemia can lead to serious complications 1

4. Overlooking multigland disease: Focusing only on a single adenoma when multiple glands are involved can lead to persistent disease 1

5. Inadequate follow-up: Even after successful surgery, monitoring calcium and PTH levels is essential to detect recurrence 1

Primary hyperparathyroidism is a common endocrine disorder with significant morbidity if left untreated. Surgical intervention remains the gold standard treatment with excellent outcomes when performed by experienced surgeons.