What is the diagnosis and management for an elderly female with hypercalcemia and elevated PTH?

Primary Hyperparathyroidism

This elderly female patient has primary hyperparathyroidism (PHPT), as evidenced by hypercalcemia (10.7 mg/dL) with an inappropriately elevated PTH (61.1 pg/mL), and the definitive treatment is parathyroidectomy. 1

Diagnosis Confirmation

The laboratory values confirm PHPT through the following findings:

• Calcium of 10.7 mg/dL is elevated (normal upper limit ~10.2-10.5 mg/dL), meeting criteria for hypercalcemia 1
• PTH of 61.1 pg/mL is inappropriately normal-to-elevated in the setting of hypercalcemia, which is diagnostic of PTH-mediated hypercalcemia 2, 3
• Vitamin D level of 57.4 ng/mL is adequate, ruling out vitamin D deficiency as a cause of secondary hyperparathyroidism 1
• Normal renal function (creatinine 0.87) excludes chronic kidney disease as a cause of secondary hyperparathyroidism 4
• Normal phosphorus (3.4 mg/dL) is consistent with PHPT 1

A critical point: PTH levels between 40-88 pg/mL are technically "normal" but are inappropriately elevated when hypercalcemia is present. Recent surgical series demonstrate that patients with hypercalcemia and PTH ≤50 pg/mL have a 96.7% cure rate with parathyroidectomy, confirming these are true PHPT cases despite seemingly "normal" PTH values 3. The key concept is that any detectable PTH in the presence of hypercalcemia is inappropriate, as PTH should be suppressed to undetectable levels when calcium is elevated 2, 3.

Recommended Diagnostic Workup

Parathyroid imaging should be obtained to localize the adenoma prior to surgery:

• Sestamibi scan (99mTc-sestamibi) with SPECT/CT is the primary imaging modality 2
• Neck ultrasonography to identify parathyroid adenomas 2
• Consider 4D-CT if initial imaging is non-localizing 2

Important caveat: Patients with PTH ≤50 pg/mL have a significantly higher rate of multiglandular disease (58.9% vs 31.9% in those with PTH >50 pg/mL), which may require bilateral neck exploration rather than focused parathyroidectomy 3.

Management Strategy

Definitive Treatment

Parathyroidectomy is indicated for this patient based on:

• Hypercalcemia meeting surgical criteria (calcium >10.5 mg/dL) 5
• Presence of biochemical PHPT 1

Surgical approach considerations:

• If preoperative imaging localizes a single adenoma, focused parathyroidectomy may be performed 3
• Given the PTH level of 61.1 pg/mL, bilateral neck exploration should be strongly considered due to the higher likelihood of multiglandular disease 3
• Intraoperative PTH monitoring should be used to confirm adequate resection 6

Medical Management (If Surgery Declined or Contraindicated)

If the patient cannot undergo parathyroidectomy, cinacalcet is FDA-approved for this indication:

• Cinacalcet 30 mg twice daily as initial dose, titrated every 2 weeks to maximum 90 mg four times daily 5
• Target serum calcium ≤10.3 mg/dL 5
• In clinical trials, 75.8% of patients achieved target calcium levels with median dose of 60 mg/day 5
• Monitor serum calcium closely during titration to avoid hypocalcemia 5

Important warning: Cinacalcet should be used with extreme caution as it has been associated with severe adverse effects including hypocalcemia and increased QT interval 1

Monitoring Parameters

Preoperative monitoring:

• Assess for symptoms of hypercalcemia (fatigue, cognitive changes, bone pain, kidney stones) 3
• Screen for complications: bone density assessment, renal function, kidney stone evaluation 1

Postoperative monitoring:

• Immediate postoperative calcium monitoring is critical as hungry bone syndrome can occur, particularly in patients with elevated PTH 6
• Monitor for hypocalcemia symptoms (paresthesias, Chvostek's sign, Trousseau's sign) 4
• Calcium and PTH levels should be checked within 1-2 weeks postoperatively 6

Common Pitfalls to Avoid

• Do not dismiss this as "normal PTH" – any detectable PTH with hypercalcemia is inappropriate and diagnostic of PHPT 2, 3
• Do not attribute hypercalcemia to vitamin D supplementation when PTH is elevated, as this represents autonomous parathyroid function 1
• Do not assume single-gland disease – patients with PTH in this range have nearly 60% multiglandular disease requiring bilateral exploration 3
• Do not use cinacalcet as first-line therapy when surgery is feasible, as parathyroidectomy is curative with 96.7% success rate 5, 3