Anesthesia for Parathyroidectomy 

🔍 Introduction

Parathyroidectomy is the surgical removal of one or more parathyroid glands. It is most commonly performed for:

• Primary hyperparathyroidism (PHPT): Caused by parathyroid adenoma (80–85%), hyperplasia (10–15%), or carcinoma (<1%)
• Secondary hyperparathyroidism: Often due to chronic kidney disease
• Tertiary hyperparathyroidism: Autonomous gland activity after long-standing secondary HPT (usually post-renal transplant)

⚙️ Pathophysiology of Hyperparathyroidism

🧪 Parathyroid Hormone (PTH) Effects:

• Increases bone resorption → ↑ Serum calcium
• Enhances renal reabsorption of Ca²⁺
• Promotes activation of vitamin D → ↑ GI absorption of Ca²⁺
• ↓ Serum phosphate (↑ excretion)

📋 Clinical Features:

• Bones: Osteitis fibrosa cystica, bone pain, fractures
• Stones: Nephrolithiasis
• Groans: Abdominal pain, pancreatitis, PUD
• Moans: Psychiatric symptoms like depression, confusion
• Cardiac: Hypertension, short QT interval, arrhythmias

👩‍⚕️ Preoperative Evaluation

✅ History:

• Renal colic, fractures, psychiatric symptoms
• Symptoms of hypercalcemia: polyuria, polydipsia, constipation
• Evaluate for MEN syndromes (Multiple Endocrine Neoplasia):
• MEN 1: Pituitary, parathyroid, pancreas
• MEN 2A: Medullary thyroid carcinoma, pheochromocytoma, parathyroid
• MEN 2B: Medullary thyroid carcinoma, pheochromocytoma, mucosal neuromas

✅ Lab Tests:

• Serum calcium, phosphate, magnesium, albumin
• PTH levels
• 25(OH) Vitamin D
• Renal function tests
• ECG: Look for short QT, arrhythmias
• Urinalysis: Nephrolithiasis

✅ Imaging:

• Neck ultrasound
• Sestamibi scan
• 4D-CT/MRI

✅ Optimization:

• Hydration with normal saline to correct volume depletion
• Bisphosphonates for hypercalcemia
• Calcitonin, steroids, diuretics (loop diuretics like furosemide after hydration)
• Stop thiazide diuretics and lithium (increase Ca²⁺)

🛏️ Anesthetic Goals

💉 Choice of Anesthesia

✅ General Anesthesia (GA)

• Most common approach.
• Facilitates airway control, neuromonitoring, and rapid emergence.

Induction:

• Standard agents: Propofol, fentanyl, rocuronium (if no RLN monitoring)
• Avoid succinylcholine if hyperkalemia is suspected

Maintenance:

• Volatile agents (sevoflurane/desflurane)
• Short-acting opioids: Remifentanil preferred
• BIS monitoring for rapid emergence
• Muscle relaxants: Use short-acting; avoid if using nerve monitoring (NIM tube)

Airway:

• Anticipate difficult airway in reoperations or MEN syndromes (goiter, previous surgeries)
• Consider NIM endotracheal tube for intraoperative RLN monitoring

✅ Regional Anesthesia

• Rare but possible (e.g., cervical plexus block), mostly in high-risk patients
• Requires cooperative patient, not ideal for bilateral or complex exploration

🔬 Intraoperative Considerations

• Positioning: Reverse Trendelenburg, slight neck extension. Support head and avoid cervical spine strain.
• Recurrent Laryngeal Nerve Monitoring: Avoid long-acting neuromuscular blockers if used.
• Intraoperative PTH monitoring:
• PTH half-life ~2–5 minutes
• Drop of >50% from baseline at 10 minutes after gland removal = adequate resection

Postoperative Concerns

⚠️ Hypocalcemia:

• Due to “hungry bone syndrome” or removal of hyperfunctioning gland
• Monitor ionized calcium frequently
• Symptoms: Perioral numbness, tingling, tetany, carpopedal spasm (Trousseau’s sign), laryngospasm

Management:

• Oral or IV calcium gluconate
• Magnesium and vitamin D supplementation as required

⚠️ Vocal Cord Dysfunction:

• RLN injury → Hoarseness, aspiration, stridor
• Evaluate with laryngoscopy if suspected

🩺 Postoperative Monitoring

• Calcium levels: Q6–8 hourly for first 24–48 hours
• ECG monitoring: For QT prolongation, arrhythmias
• Pain control: Mild pain, usually managed with paracetamol or NSAIDs
• Watch for signs of hematoma causing airway compression—surgical emergency!

💡 Special Situations

In CKD patients (Secondary HPT):

• Increased risk of bleeding
• Difficult IV access
• Avoid nephrotoxic drugs
• Monitor fluid status carefully

In MEN Syndrome:

• Evaluate and treat pheochromocytoma before surgery
• Anticipate difficult airway, endocrinopathies

📘 Viva Questions & High-Yield Pearls

✅ MCQ Nuggets

1. Best IV calcium salt for symptomatic hypocalcemia?
   → Calcium gluconate
2. Effect of hypercalcemia on QT interval?
   → Shortened QT
3. Half-life of PTH?
   → 2–5 minutes
4. Gold standard for localizing adenoma?
   → Sestamibi scan
5. Drug avoided in RLN monitoring?
   → Long-acting neuromuscular blockers
6. Best initial fluid for hypercalcemia?
   → Normal saline