Endocrine: Primary Hyperparathyroidism

Primary Hyperparathyroidism

Definition

  • Hypersecretion of PTH from the Parathyroid Gland
  • Causes:
    • Single Parathyroid Adenoma (80%)
    • Four-Gland Parathyroid Hyperplasia (10-15%)
    • 2-3-Gland Parathyroid Adenomas (4%)
    • Parathyroid Adenocarcinoma (1%)

Presentation

  • Most are Asymptomatic
  • Symptoms of Hypercalcemia:
    • Nephrolithiasis
    • Osteoporosis
    • Abdominal Pain
    • Urinary Frequency
    • Fatigue & Delirium
  • Osteitis Fibrosa Cystica
    • Brown Tumors from Ca Resorption

Diagnosis

  • Diagnosis: Labs & Urine Calcium
    • Labs:
      • High Calcium
      • Low Phosphorus
      • High Chloride
      • Acidosis
    • Urine: High Urine Calcium
      • Rules Out Familial Hypercalcemic Hypocalciuria
      • Calcium-to-Creatinine Clearance Ratio > 0.02
    • Most Specific Indicator: High Cl/Phos Ratio > 33
  • Localization: US & Sestamibi Scan (Technetium 99m)
    • US May Also Find Concomitant Thyroid Pathology
    • 4-D CT May Also Be Available at Some Centers

Concerning Signs for Adenocarcinoma

  • Symptomatic
  • Palpable Parathyroid Tumor
  • Calcium > 13 mg/dL
    • Mortality is Generally from Hypercalcemia
  • US: Irregular & Fixed to Adjacent Tissue
    • No FNA Indicated (Risk for Seeding)
  • Intraoperatively: Adherent & Invading Thyroid with No Clear Plane

Surgery Indications

  • Symptoms of Hypercalcemia
  • Serum Calcium > 1.0 mg/dL Above Normal Upper Limit
  • Renal Involvement:
    • GFR < 60 mL/min
    • Nephrolithiasis
    • 24-Hour Urine Calcium > 400 mg/Day
  • Significant Bone Loss (T-Score < – 2.5)
  • Age < 50

Surgical Treatment

  • Adenoma: Minimally Invasive (Focused) Parathyroidectomy
  • Hyperplasia or MEN I/IIa: Bilateral Neck Exploration
    • 1-3 Enlarged: Resect All Diseased Glands
    • 4 Enlarged: Subtotal (3.5 Gland) Resection or Total Parathyroidectomy with Autoimplantation
      • Preferred Method Debated
      • Subtotal (3.5 Gland) Risks Neck Reoperation
      • Total Risks Hypoparathyroidism
  • Adenocarcinoma: Radical Parathyroidectomy (En Bloc Resection with Thyroid Lobectomy)
    • No Need for Prophylactic Lymph Node Dissection – High Morbidity with Low Risk of Metastases

Parathyroid Adenoma (White Arrow) and Normal Parathyroid (Black Arrow) 1

Parathyroid Adenoma on US 2

Parathyroid Adenoma on Sestamibi Scan 3

References

  1. Bendinelli C, Nebauer S, Quach T, Mcgrath S, Acharya S. Is minimally invasive parathyroid surgery an option for patients with gestational primary hyperparathyroidism? BMC Pregnancy Childbirth. 2013 Jun 11;13:130. (License: CC BY-2.0)
  2. Dilman N. Wikimedia Commons. (License: CC BY-SA-3.0)
  3. Ozaki A, Tanimoto T, Yamagishi E, Sato S, Tsukada M, Sawano T, Leppold C, Tsuda K, Asakura T, Tsubokura M, Kato S, Kami M, Ohira H. Finger Fractures as an Early Manifestation of Primary Hyperparathyroidism Among Young Patients: A Case Report of a 30-Year-Old Male With Recurrent Osteoporotic Fractures. Medicine (Baltimore). 2016 May;95(20):e3683. (License: CC BY-4.0)