Hyperparathyroidism
Background
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Primary hyperparathyroidism: parathyroid adenoma or carcinoma
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Secondary hyperparathyroidism: an appropriate compensatory response of the parathyroid glands to counteract a disease process that produces hypocalcemia
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Ectopic hyperparathyroidism: due to secretion of parathyroid hormone (or a substance with similar endocrine effects) by tissues other than the parathyroid glands
Considerations
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Potential difficult airway:
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Mass effect (goitre)
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Osteopenic bone (pathologic fractures of mandible & vertebral bodies)
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Physiologic changes of hypercalcemia:
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CNS: ↓LOC, hallucinations, psychosis
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Cardiovascular: hypertension, hypovolemia, conduction blockade
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Hypercalcemia ECG: ↑PR interval, ↓QTc
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Respiratory: potential respiratory muscle weakness, poor clearance of secretions
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Renal: renal failure, nephrolithiasis (70%)
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GI: ↑ aspiration risk, nausea/vomiting, abdominal pain, pancreatitis
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MSK: weakness (titrate neuromuscular blockers to effect), pathologic fractures (careful positioning)
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Hematologic: anemia
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Underlying etiology:
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Parathyroid tumour, PTH-producing tumour
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Chronic renal failure (usually associated with hypocalcemia, hyperphosphatemia)
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Considerations of cancer & associated syndromes (MEN 1):
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MEN 1: hyperparathyroid, pancreatic islet cell tumors, pituitary hyperplasia or tumor
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MEN 2A: hyperparathyroid, medullary thyroid carcinoma, pheochromocytoma
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Post-op airway obstruction after parathyroidectomy:
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Hematoma, laryngospasm, hypocalcemia, recurrent laryngeal nerve injury, tracheomalacia
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Mandibular fracture
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Optimization
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Management of hypercalcemia:
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IV rehydration
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Furosemide after IV hydration → goal is 3-5 L urine output/day
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If severe, add:
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Bisphosphonate (etidronate 7.5mg/kg IV OD or 20mg/kg PO OD)
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Calcitonin 200 IU nasal spray/day
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IV steroids
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Phosphate repletion
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Hemodialysis if life threatening hypercalcemia or acute renal failure
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Monitor EKG & calcium concentrations perioperatively
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Prevent pathological fractures (careful positioning)
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Airway vigilance postoperatively
Conflicts
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Hypovolemia vs. RSI (ESWL or percutaneous drainage for nephrolithiasis)
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Renal failure vs. succinylcholine for RSI