From the Research
Yes, surgery and anesthesia can potentially affect your TSH levels temporarily, and it is recommended to wait 4-6 weeks after surgery for a follow-up thyroid test to assess if your levels have stabilized. The stress response from surgery triggers hormonal changes in your body, including the release of cortisol and other stress hormones that can influence thyroid function, as discussed in various studies 1, 2, 3, 4, 5. Local anesthesia itself typically has minimal impact on thyroid tests, but the surgical procedure and associated stress can cause fluctuations. This is known as "non-thyroidal illness syndrome" or "euthyroid sick syndrome," where thyroid hormone levels may change during physical stress without indicating actual thyroid disease. Some key points to consider:
- The changes in thyroid hormone levels after surgery are usually temporary and should return to your normal baseline within a few weeks after surgery.
- It is essential to monitor for any symptoms of thyroid dysfunction, such as unusual fatigue, weight changes, or temperature sensitivity, but try not to worry as these post-surgical fluctuations are common and typically resolve on their own.
- A study published in the Journal Anesthesia and analgesia 4 found that the risk of 30-day morbidity and mortality was not different with blood testing up to 2 months before surgery, suggesting that it is unnecessary to retest patients shortly before surgery.
- Another study published in the European journal of endocrinology 3 discussed the therapy of endocrine disease, specifically the T4 + T3 combination therapy, and its potential effects on thyroid function.
- The American family physician 2 published a study on hypothyroidism, diagnosis, and treatment, which provides valuable information on the diagnosis and management of thyroid disease.
- A study published in the Gynecological endocrinology journal 5 discussed thyroid function and postmenopause, highlighting the importance of routine screening of thyroid function in the climacteric period to determine subclinical thyroid disease. In your case, since your TSH was normal a few days before your surgery, it is likely that the surgery and associated stress caused the temporary fluctuations in your thyroid hormone levels. I would recommend a follow-up thyroid test in 4-6 weeks to see if your levels have stabilized, and in the meantime, watch for any symptoms of thyroid dysfunction.