Learning objectives

• Describe hyperparathyroidism
• Recognize the symptoms and signs of hypercalcemia, related to hyperparathyroidism
• Anesthetic management of a patient with hyperparathyroidism

Definition and mechanisms

• Hyperparathyroidism (HPT) is a condition in which the parathyroid glands produce too much parathyroid hormone (PTH)
• PTH plays an important role in maintaining normal calcium homeostasis
• The main effector sites responding directly or indirectly to PTH are the intestines, kidneys, and bone
• HPT ultimately results in hypercalcemia

Classification

• Primary HPT: Hyperfunction of the parathyroid glands (i.e., adenoma, carcinoma, or hyperplasia) leading to an overproduction of PTH
• Secondary HPT: Appropriate compensatory response of the parathyroid glands to secrete more PTH in response to a condition (i.e., chronic kidney disease, vitamin D deficiency) that produces hypocalcemia
• Tertiary HPT: Long-standing secondary HPT starts to behave like primary HPT, usually associated with advanced kidney failure
• Ectopic HPT: Secretion of PTH by tissues other than the parathyroid glands

Signs and symptoms

The symptoms of HPT are caused by hypercalcemia:

• Cardiovascular: Hypertension, shortened QT interval, prolonged PR interval, hypovolemia, conduction blockade
• Neurological: Mental status changes, weakness, lethargy
• Respiratory: Potential respiratory muscle weakness, poor clearance of secretions
• Musculoskeletal: Muscle weakness, osteoporosis, pathological fractures, bone pains
• Gastrointestinal: Abdominal pain, peptic ulcer, pancreatitis, nausea/vomiting, ↑ aspiration risk
• Renal: Polyuria, polydipsia, renal stones, renal failure
• Hematopoietic: Anemia

Risk factors

• Age: Older adults (>60 years) 
• Sex: Female sex
• Genetic conditions: Multiple endocrine neoplasia syndromes (MEN)

Pathophysiology

Treatment

• Primary HPT: Parathyroidectomy
• Secondary HPT: Treat underlying cause (i.e., chronic kidney failure, vitamin D deficiency)
• Tertiary HPT: Parathyroidectomy
• Calcimimetics are used in patients with primary HPT unable to undergo parathyroidectomy and for patients with secondary HPT on dialysis

Management

Suggested reading

• Malhotra S, Sodhi V. Anaesthesia for thyroid and parathyroid surgery. Continuing Education in Anaesthesia Critical Care & Pain. 2007;7(2):55-58.