What is the management approach for a patient with primary hyperparathyroidism (PHPT) presenting with dizziness?

Management of Dizziness in Primary Hyperparathyroidism

Dizziness in a patient with primary hyperparathyroidism (PHPT) is most commonly a nonspecific symptom of hypercalcemia rather than a direct indication for immediate intervention, and management should focus on confirming the diagnosis, assessing disease severity, and determining surgical candidacy based on established criteria.

Initial Diagnostic Approach

The presence of dizziness warrants immediate assessment of the severity of hypercalcemia and evaluation for other potential causes:

• Measure serum calcium levels immediately to determine if hypercalcemia is mild (<12 mg/dL), moderate (12-14 mg/dL), or severe (≥14 mg/dL), as this dictates urgency of management 1
• Confirm PHPT diagnosis biochemically by measuring serum calcium (corrected for albumin) and intact PTH simultaneously—inappropriately elevated or "normal" PTH in the setting of hypercalcemia confirms PHPT 2, 3
• Assess vitamin D status (25-hydroxyvitamin D), as deficiency can complicate PTH interpretation and cause secondary hyperparathyroidism 3
• Evaluate for alternative causes of dizziness including orthostatic hypotension, dehydration, medications (particularly if patient has comorbid heart failure or is on antihypertensives), vestibular disorders, and cardiovascular causes 4

Severity-Based Management Algorithm

Mild Hypercalcemia (<12 mg/dL) with Dizziness

Most patients with PHPT present asymptomatically or with mild nonspecific symptoms like dizziness, which affects approximately 20% of patients 1, 5:

• Dizziness alone does not constitute an indication for urgent parathyroidectomy unless other surgical criteria are met 2, 3
• Evaluate for surgical indications including age <50 years, serum calcium >1 mg/dL above upper normal limit, impaired kidney function (GFR <60 mL/min/1.73 m²), nephrolithiasis, nephrocalcinosis, or osteoporosis on DEXA scan 3, 5
• If surgical criteria are met, proceed with parathyroidectomy, which is the only curative treatment and provides symptomatic improvement including resolution of nonspecific symptoms 2, 3
• If surgery is not indicated or patient declines, provide patient education about maintaining adequate hydration, optimizing calcium intake per age-related dietary allowances (do not restrict calcium), and ensuring vitamin D repletion to ≥50 nmol/L (20 ng/mL), with a goal of ≥75 nmol/L (30 ng/mL) being reasonable 6, 5

Moderate to Severe Hypercalcemia (≥12 mg/dL) with Symptomatic Dizziness

Severe hypercalcemia (≥14 mg/dL) or rapidly developing hypercalcemia can cause nausea, vomiting, dehydration, confusion, somnolence, and coma, requiring urgent intervention 1:

• Initiate immediate treatment with intravenous normal saline hydration, which reduces calcium from approximately 3.25 mmol/L to 2.98 mmol/L over 3 days 7
• Administer intravenous zoledronic acid or pamidronate as first-line pharmacologic therapy, which reduces serum calcium by approximately 0.57 mmol/L and achieves normocalcemia in 60% of patients 1, 7
• Avoid furosemide as it provides no additional benefit beyond saline hydration alone and may worsen dehydration 7
• Arrange urgent parathyroidectomy once patient is stabilized, as this is definitive treatment for symptomatic PHPT 3, 1

Medical Management for Non-Surgical Candidates

For patients who cannot or will not undergo surgery, medical management options exist but do not cure the underlying disease 6, 5:

Calcimimetic Therapy

• Cinacalcet is FDA-approved for hypercalcemia in primary HPT patients unable to undergo parathyroidectomy 8
• Starting dose is 30 mg twice daily, titrated every 2-4 weeks through sequential doses up to 90 mg four times daily to normalize serum calcium 8
• Cinacalcet effectively lowers serum calcium to normal in many cases (75.8% achieve calcium ≤10.3 mg/dL) but has only modest effects on PTH levels and does not improve bone mineral density 8, 6
• Monitor serum calcium within 1 week after initiation or dose adjustment, then every 2 months once stable 8
• Use with caution due to risk of hypocalcemia and increased QT interval 4, 8

Bone Protection

• Bisphosphonate therapy (particularly alendronate) improves BMD at the lumbar spine without altering serum calcium concentration and should be used in patients with increased fracture risk 6, 5
• Combination therapy with cinacalcet and bisphosphonates is reasonable to address both hypercalcemia and bone density, though strong evidence for this approach is lacking 6

Critical Pitfalls to Avoid

• Do not attribute dizziness solely to PHPT without excluding other causes, particularly in elderly patients with multiple comorbidities or those on cardiovascular medications 4
• Do not restrict calcium intake in PHPT patients, as this can worsen secondary hyperparathyroidism; instead, ensure age-appropriate dietary calcium intake 6, 5
• Do not delay vitamin D repletion out of fear of worsening hypercalcemia; patients with low 25-hydroxyvitamin D should be repleted to at least 50 nmol/L 6, 5
• Do not discharge patients with mild hypercalcemia from acute care settings without a definitive follow-up plan, as 24% of such patients lack a primary care physician and 81% have symptoms referable to hypercalcemia 9
• Do not use furosemide routinely in severe hypercalcemia management, as it provides no additional benefit and may cause harm 7

Surgical Planning When Indicated

When parathyroidectomy is indicated, preoperative localization studies guide the surgical approach 2, 10:

• Obtain sestamibi scan (99Tc-Sestamibi), ultrasound, or 4D-CT for preoperative localization 10, 3
• Minimally invasive parathyroidectomy (MIP) is preferred when a single adenoma is confidently localized, offering shorter operating times, faster recovery, and decreased costs 10, 3
• Bilateral neck exploration (BNE) is required for discordant/nonlocalizing imaging or suspected multigland disease 10
• Intraoperative PTH monitoring confirms removal of the hyperfunctioning gland during MIP 10