From the Research
Uncontrolled hypothyroidism significantly increases the risk of perioperative complications, and thus, it is crucial to address this condition before elective surgery. The most recent and highest quality study 1 provides insight into the management of thyroid dysfunction in the perioperative period, although it focuses on hyperthyroidism, the principles of careful management and consideration of thyroid function before surgery are applicable.
Key Considerations
- Patients with severe hypothyroidism (myxedema) should have their surgery postponed until their thyroid function improves to mitigate the risks of cardiovascular complications, impaired drug metabolism, and poor wound healing.
- For patients with mild to moderate hypothyroidism, surgery may proceed with careful monitoring, emphasizing the importance of preoperative evaluation and management.
- Treatment involves levothyroxine (T4) replacement, typically starting at 1.6 mcg/kg/day, with dose adjustments based on TSH levels every 6-8 weeks, as supported by earlier studies 2, 3.
- In urgent surgical situations where postponement isn't possible, perioperative management should include stress-dose steroids if adrenal insufficiency is suspected, careful temperature monitoring to prevent hypothermia, judicious use of sedatives and anesthetics due to increased sensitivity, and close cardiovascular monitoring.
Perioperative Risks
The risks associated with uncontrolled hypothyroidism in the perioperative period stem from its physiological effects, including:
- Decreased cardiac output
- Bradycardia
- Impaired respiratory drive
- Altered drug metabolism
- Electrolyte abnormalities Ideally, TSH levels should be normalized before elective procedures to minimize these complications, as suggested by studies focusing on the importance of preoperative thyroid function optimization 4, 5.
Management Approach
Given the potential for increased perioperative risk, a careful and individualized approach to the management of patients with hypothyroidism undergoing surgery is necessary. This includes thorough preoperative evaluation, consideration of the severity of hypothyroidism, and adjustment of treatment regimens as necessary to ensure the best possible outcomes. While the most recent study 1 does not directly address hypothyroidism, its emphasis on the safe management of thyroid dysfunction in the perioperative period underscores the importance of careful consideration and management of thyroid status before surgery.