BACKGROUND
Hyperthyroidism, where the thyroid gland makes too much thyroid hormone. The most common cause of hyperthyroidism is Graves’ disease, an autoimmune condition where an antibody stimulating the thyroid gland leads to diffuse increase in thyroid hormone production. Other causes of hyperthyroidism include a toxic multinodular goiter or toxic adenoma, where one or more thyroid nodules become overactive. Symptoms of hyperthyroidism can vary depending on the severity of the disease. Severe hyperthyroidism can cause problems such as irregular heartbeat or heart failure. Rarely, it can lead to “thyroid storm” which is the most severe form of hyperthyroidism, and which requires management in an intensive care unit and can lead to death.

Thyroid surgery (thyroidectomy) is an effective treatment for hyperthyroidism, especially for toxic multinodular goiters or toxic adenomas, as these disorders do not go into remission and require long term antithyroid drug treatment. Surgery is less commonly recommended for treating Graves’ disease, as this disorder can go into remission. Ideally, patients’ thyroid hormone levels should be normal on antithyroid medications before surgery to minimize risk of surgical complications and worsening of hyperthyroidism due to manipulation of the thyroid gland during surgery. However, in cases of severe hyperthyroidism needing urgent surgery or in cases where patients cannot take antithyroid medications due to allergy or side effects, surgery may need to be done when thyroid hormone levels are still high.

The authors of this study evaluated the currently available studies comparing potential differences in surgical complications in patients with hyperthyroidism who had normal thyroid levels (euthyroid) and those who still had high thyroid levels (hyperthyroid) before thyroidectomy for hyperthyroidism.

THE FULL ARTICLE TITLE
Lincango EP et al Safety of surgery for managing hyperthyroidism in patients with or without preoperative euthyroidism: a systematic review and meta-analysis. Endocrine. Epub 2025 Jul 14; doi: 10.1007/s12020-025-04340-6. PMID: 40658187.

SUMMARY OF THE STUDY
The authors included 1336 patients from 6 studies to perform a meta-analysis, where the data from several studies were combined to better evaluate a common question. Thyroidectomy was performed because of inadequate control of hyperthyroidism with medication in most cases. About 1/3rd of patients did not have normal thyroid hormone levels at the time of thyroidectomy.

Surgical complications studied included hypocalcemia (low calcium levels that can occur due to damage to parathyroid glands), hematoma (collection of blood) that required surgical drainage, and recurrent laryngeal nerve injury (a nerve that passes next to the thyroid gland whose damage can lead to voice problems). There were no differences in the rates of surgical complications between euthyroid patients and hyperthyroid patients. There were also no significant differences in length of hospital stay or surgery time between the two groups. Thyroid storm occurred in only one hyperthyroid patient and none in euthyroid patients.

WHAT ARE THE IMPLICATIONS OF THIS STUDY?
The authors concluded that not having normal thyroid hormone levels before thyroidectomy for hyperthyroidism did not lead to a clear increase in surgical complications. The findings of this study support the safety of thyroidectomy in emergency settings when achieving normal thyroid hormone levels may take too long or be difficult.

It should be noted that only two studies contributed most of the data and that none of the studies included patients who were not completely untreated, as they were just not fully controlled.

Having normal thyroid hormone levels prior to thyroidectomy appear to have benefit, such as decrease in bleeding, even though the rates were not different enough to reach the statistical significance. It is also important to keep in mind that the safety of thyroid surgery is known to vary with surgical expertise. A high-volume thyroid surgeon who performs many thyroidectomies routinely would be able to handle potential complications would have fewer surgical complications than a low-volume thyroid surgeon. Therefore, it would be safest for patient to achieve normal thyroid hormone levels before surgery, but surgery may be performed safely in cases of emergency or urgent need.

— Sun Y. Lee, MD

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