What are the potential adverse responses to a Dilation and Curettage (D&C) procedure in a patient with hyperthyroidism?

Potential Adverse Responses to D&C in Hyperthyroid Patients

Patients with hyperthyroidism undergoing dilation and curettage (D&C) procedures face increased cardiovascular risks and should be medically stabilized with beta-blockers prior to surgery, even if biochemical euthyroidism cannot be achieved.

Cardiovascular Risks and Complications

• Hyperthyroidism significantly affects the cardiovascular system, causing increased cardiac output (up to 300% above normal), decreased systemic vascular resistance, and increased blood volume (up to 25%) 1
• Patients may present with tachycardia, hypertension, and in severe cases, heart failure symptoms due to the direct effects of excess thyroid hormones on cardiac function 1
• Pulmonary artery hypertension can occur in hyperthyroid patients, increasing the load on the right ventricle and potentially causing right ventricular dilation 1
• Atrial fibrillation is common in hyperthyroid patients (5-15%), particularly in those over 60 years of age, which increases the risk of perioperative complications 1

Anesthetic and Surgical Risks

• Hyperthyroid patients are at risk for intraoperative hemodynamic instability, including tachycardia, hypertension, and hyperthermia 2, 3
• Traditionally, it has been recommended that hyperthyroid patients should be rendered euthyroid before any surgical procedure to prevent thyroid storm, though recent evidence suggests this may not always be necessary 2, 3, 4
• Increased intraoperative beta-blocker use is typically required in hyperthyroid patients to control heart rate and blood pressure during surgery 3

Preoperative Management

• Beta-blockers should be initiated before the D&C procedure to control heart rate and improve cardiovascular symptoms, even if biochemical euthyroidism cannot be achieved 1, 2
• The goal of beta-blocker therapy is to lower the heart rate to nearly normal, which will improve the tachycardia-mediated component of ventricular dysfunction 1
• In cases where antithyroid drugs cannot be tolerated or there is insufficient time to achieve euthyroidism, surgery can still be performed safely with appropriate cardiovascular stabilization 5, 4
• For patients with moderate to severe hyperthyroidism, a combination therapy approach may be necessary, including beta-blockers, iodine, corticosteroids, and possibly cholestyramine 2

Thyroid Storm Risk

• Thyroid storm is a rare but potentially life-threatening complication that can be triggered by surgical stress in inadequately prepared hyperthyroid patients 1
• Signs of thyroid storm include hyperthermia, tachycardia, hypertension or hypotension, and altered mental status 1
• Recent studies suggest that with proper perioperative management, the risk of thyroid storm during surgery in hyperthyroid patients is low, even when biochemical euthyroidism has not been achieved 5, 4

Specific Recommendations for D&C in Hyperthyroid Patients

• Evaluate thyroid function tests (TSH, free T4, free T3) before the procedure 1, 2
• Start beta-blockers (e.g., atenolol or propranolol) for symptomatic relief and cardiovascular stabilization 1
• For patients with mild to moderate hyperthyroidism who are cardiovascularly stable on beta-blockers, D&C can proceed without delaying for complete biochemical control 3, 4
• For severe hyperthyroidism or cardiovascular instability, consider delaying elective D&C until better control is achieved 2
• Monitor for signs of thyroid storm during and after the procedure, including hyperthermia, tachycardia, and hemodynamic instability 1
• Ensure adequate hydration and supportive care throughout the perioperative period 1

Special Considerations

• Patients with underlying cardiac disease are at higher risk for complications when hyperthyroidism is present 1
• Elderly patients with hyperthyroidism require particularly careful management as cardiovascular complications are the chief cause of death after treatment of hyperthyroidism 1
• Patients with a history of thyroid storm are at higher risk and may require more aggressive preoperative preparation 4

Post-Procedure Monitoring

• Continue monitoring for signs of thyroid storm for 24-48 hours post-procedure 1
• Maintain beta-blocker therapy until thyroid function is controlled 1
• Monitor for temporary hypocalcemia, which may be more common in uncontrolled hyperthyroid patients undergoing thyroid surgery (though less relevant for D&C) 4