Can a patient with uncontrolled hyperthyroidism undergo surgery for an acute kidney stone?

Management of Hyperthyroidism in a Patient Requiring Kidney Stone Surgery

Surgery for acute kidney stones in a patient with uncontrolled hyperthyroidism (TSH 0.001, elevated free T4 and T3) should be delayed until the hyperthyroid state is controlled with medical therapy to reduce perioperative cardiovascular complications.

Preoperative Risk Assessment

Uncontrolled hyperthyroidism presents significant perioperative risks:

• Cardiovascular instability: Hyperthyroidism causes tachycardia, increased cardiac output, and potential arrhythmias
• Risk of thyroid storm: While recent evidence suggests this risk may be lower than historically thought 1, it remains a serious concern
• Intraoperative hypotension: More common in patients with thyroid dysfunction 2

Medical Management Before Surgery

The patient requires rapid preoperative preparation with a combination approach:

1. Thionamides (Methimazole):

   • First-line therapy to block new thyroid hormone synthesis
   • Typical starting dose: 10-30 mg daily (divided doses) 3
   • Monitor for side effects including agranulocytosis, hepatotoxicity

2. Beta-blockers:

   • Add propranolol (40 mg every 8 hours) to control sympathetic symptoms
   • Helps manage tachycardia and other cardiovascular manifestations

3. Consider adjunctive therapy for rapid control:

   • Iodine solutions (Lugol's solution or saturated solution of potassium iodide)
   • Corticosteroids for severe cases

Monitoring and Timing of Surgery

• Monitor thyroid function tests every 1-2 weeks
• Surgery should ideally be delayed until:
  • Clinical symptoms of hyperthyroidism improve
  • Free T4 and T3 levels approach normal range
  • Heart rate and blood pressure normalize

Special Considerations for Kidney Stone Management

• If the kidney stone is causing complete obstruction, sepsis, or refractory pain:
  • Consider temporary decompression with nephrostomy or stent placement under local anesthesia
  • This allows time for hyperthyroidism control before definitive surgery

Recent Evidence on Surgery in Hyperthyroid Patients

While traditional teaching recommends achieving euthyroidism before surgery, recent research provides nuanced perspectives:

• A 2023 retrospective study of 275 hyperthyroid patients found that thyroidectomy could be performed safely in uncontrolled patients without precipitating thyroid storm 1
• However, uncontrolled patients had:
  • Longer operative times
  • Increased blood loss
  • Higher rates of temporary hypocalcemia

Anesthetic Considerations

If urgent surgery is absolutely necessary before achieving euthyroidism:

• Involve anesthesiology early for specialized planning
• Ensure availability of beta-blockers, vasopressors, and antiarrhythmics in the operating room
• Monitor for hypotension, which occurs more frequently in thyroid dysfunction 2
• Have treatment for thyroid storm readily available

Conclusion

While some recent evidence suggests surgery may be performed safely in hyperthyroid patients 1, the traditional approach of controlling hyperthyroidism before elective surgery remains prudent, especially for non-thyroid surgeries where the benefit-risk calculation differs. The FDA drug label for methimazole specifically indicates its use "to ameliorate symptoms of hyperthyroidism in preparation for surgery" 3, supporting this approach.

For this patient with an acute kidney stone, the optimal approach is to begin medical management of hyperthyroidism while addressing the kidney stone with the least invasive approach necessary until thyroid function improves.