Hyperparathyroidism surgical management

🧬 Pathophysiology - Gland Gone Wild

• Primary: Autonomous PTH secretion.
  • Solitary Adenoma (85%), 4-Gland Hyperplasia (15%), Carcinoma (<1%).
• Secondary: Compensatory ↑PTH from chronic hypocalcemia (e.g., Chronic Renal Failure → ↓Vit D, ↑$PO_4^{3-}$).
• Tertiary: Autonomous PTH secretion after prolonged secondary stimulation (e.g., post-renal transplant).

Core Mechanism: ↑PTH → ↑Serum $Ca^{2+}$, ↓Serum $PO_4^{3-}$.

📌 Classic Presentation: "Stones (renal), bones (pain, fractures), groans (abdominal pain), and psychiatric overtones (fatigue, depression)."

⭐ In primary hyperparathyroidism, urine calcium is high/normal. In Familial Hypocalciuric Hypercalcemia (FHH), a key mimic, urine calcium is low.

🔬 Diagnosis - Pinpointing the Problem

First, confirm biochemically: ↑ Serum Calcium ($Ca^{2+}$), ↑ PTH, ↓ Serum Phosphate ($PO_4^{3-}$), and ↑ 24-hr Urine Calcium.

⭐ The diagnostic hallmark is an elevated or inappropriately normal PTH level in the setting of hypercalcemia. This distinguishes it from other causes where PTH would be suppressed.

Next, pre-operative localization is key for planning minimally invasive surgery. The typical imaging workflow is:

• 4D-CT is particularly useful for localizing ectopic glands (e.g., mediastinal) or for re-operative cases.

🔪 Management - The Surgical Fix

• Indications for Parathyroidectomy:

  • Any symptomatic disease (e.g., nephrolithiasis, osteoporosis-related fractures).
  • Asymptomatic patients meeting any of the following criteria:
    • Age < 50 years.
    • Serum Calcium > 1.0 mg/dL above the upper limit of normal.
    • Creatinine clearance < 60 mL/min.
    • Bone density T-score ≤ -2.5 at any site.

• Surgical Procedures & Monitoring:

  • Minimally Invasive Parathyroidectomy (MIP): For pre-operatively localized single adenomas.
  • Bilateral Neck Exploration: For failed localization, suspected multigland disease (e.g., MEN), or hyperplasia.
  • 💡 Intraoperative PTH (ioPTH) - Miami Criterion: Confirms successful resection with a >50% drop from baseline 10 minutes post-removal.

⭐ Post-op, beware of Hungry Bone Syndrome: severe, prolonged hypocalcemia ($Ca^{2+}$ ↓↓) due to rapid bone remineralization. Requires aggressive calcium and vitamin D supplementation.

🤕 Complications - The Aftermath

• Hypocalcemia (Most Common)
  • Cause: Parathyroid stunning, devascularization, or removal.
  • Symptoms: Perioral numbness, paresthesias, tetany.
  • Signs: Chvostek's (facial twitch), Trousseau's (carpal spasm).
• Hungry Bone Syndrome
  • Severe, prolonged ↓$Ca^{2+}$, ↓$PO_4^{3-}$, and ↓$Mg^{2+}$.
  • Due to rapid bone remineralization after abrupt ↓PTH.
  • Seen in severe pre-op bone disease (e.g., osteitis fibrosa cystica).
• Nerve Injury
  • Recurrent Laryngeal Nerve (RLN): Unilateral → hoarseness. ⚠️ Bilateral → airway obstruction.
  • Superior Laryngeal Nerve (SLN): Loss of high-pitched voice.
• Neck Hematoma
  • ⚠️ Can rapidly cause airway compression; requires emergent evacuation.

⭐ Post-op hypocalcemia is the most frequent complication. Transient hypocalcemia is common, but permanent hypoparathyroidism occurs in <2% of cases.

⚡ Biggest Takeaways

• Primary hyperparathyroidism is most often a solitary adenoma; surgery is the only definitive cure.
• Indications: symptoms, age <50, serum Ca²⁺ >1 mg/dL above normal, or end-organ damage (osteoporosis, nephrolithiasis).
• Pre-op localization with Sestamibi scan and ultrasound enables minimally invasive parathyroidectomy.
• Intraoperative PTH (ioPTH) drop of >50% from baseline confirms successful resection.
• Key complications: recurrent laryngeal nerve injury (hoarseness) and post-op hypocalcemia ("hungry bone syndrome").
• Suspect MEN syndromes with multigland disease, often requiring subtotal parathyroidectomy.