A retrospective cohort study: Do patients with graves’ disease need to be euthyroid prior to surgery?

Abstract

BackgroundThe 2016 American Thyroid Association guidelines indicate that patients with Graves’ disease who undergo a thyroidectomy should be rendered euthyroid through the use of antithyroid drugs (ATD) prior to surgery to avoid complications such as a thyroid storm. At times, the use of ATDs can have limited efficacy and therefore some patients will inevitably remain biochemically hyperthyroid at the time of surgery.The aim of this study is to assess if hyperthyroid patients undergoing a thyroidectomy are at an increased risk of developing a thyroid storm in comparison to euthyroid patients. Furthermore, this study seeks to establish a correlation between thyroid storm identified by the levels of thyroid hormones (T3 and T4) and the level of thyroid stimulating hormone (TSH).MethodsA retrospective cohort study was conducted at two Canadian centers, one in Montreal and the other in Nova Scotia. Sixty-seven patients undergoing thyroidectomy for Graves’ disease from January 2006 to December 2016 were evaluated.ResultsThe study comprised 67 participants with a mean age of 46 years (range16–78 years). A total of 78% of patients were on methimazole, 34% on beta-blockers, 27% on potassium iodine solution, 10% on propylthiouracil and 7% on steroids. At the time of surgery 21% were in an overt hyperthyroid state and 33% were in a subclinical hyperthyroid state. The average TSH level of 0.03 mIUL/L (range 0.01–0.23 mIUL/L). Sixteen percent of patients had a TSH level less than 0.01 mIUL/L. The average free T4 level was 29.58 pmol/L (range 11.5–95.2 pmol/L). The average total T3 level was 11.52 nmol/L (range 4.5–29.1 nmol/L) and free T3 level was 6.35 pmol/L (range 6.1–6.6 pmol/L). No patient developed thyroid storm.ConclusionsIn our study, biochemically hyperthyroid patients undergoing thyroidectomy did not develop thyroid storm. Additional studies with larger sample sizes are needed to better understand the risk of thyroid storm in hyperthyroid patients.

Comparison of Intra-Operative Vital Sign Changes during Total Thyroidectomy in Patients with Controlled and Uncontrolled Graves’ Disease

“…Although TS can occur before, during, and after surgery [18,19,20,21], its incidence is very low, at 0.2 per 100,000 people [10]. The appropriate thyroid hormone level cutoffs for TS, however, remain undetermined [5]. According to Japanese guidelines, TS is associated with FT4 levels of 3–8 ng/dL [16].…”

“…Guidelines recommend that patients undergo thyroidectomy only after attaining normal ranges of thyroid hormone levels by taking ATDs. However, surgery may be performed on some patients with high thyroid hormone levels [5]. These patients may experience adverse reactions to ATDs, including agranulocytosis, hepatotoxicity or urticarial; they may be unresponsive to ATDs, or may be pregnant women who refuse high-dose ATDs, or patients who experience goiter discomfort and want a quick operation, precluding normalization of thyroid hormone levels prior to surgery [6,7].…”

“…Because the incidence of TS is only 0.2 per 100,000 people [10], few physicians have encountered this condition. Thus, cutoff values for thyroid hormones and the incidence of TS during surgery have not been determined [5]. It is thus necessary to investigate changes in vital signs that occur during thyroidectomy in Graves’ disease patients with high thyroid hormone levels, and to determine thyroid hormone cutoff levels associated with TS.…”

Surgery for Grave’s Disease

“…No significantly increased morbidity has been reported after surgery in the rapidly prepared patients and this strategy is required and is feasible in a subset of patients [44][45][46]. The occurrence of thyroid storm is rare and biochemically hyperthyroid patients may undergo thyroidectomy safely if the surgeon and anesthetist are comfortable [47]. However, the consensus remains that the outcome is best when surgery is performed on a euthyroid patient.…”

Considerations for Thyroidectomy as Treatment for Graves Disease

“…Although euthyroid is recommended in the current ATA guidelines, a few studies have found that there is no difference in outcomes for patients who are hyperthyroidic. [19][20][21] This can be important for people unable to achieve a euthyroid state or are unable to tolerate ATDs. According to the most recent ATA guidelines, preoperative potassium iodide (KI), saturated solution of potassium iodide (SSKI), or Lugol solution should be used in most patients with Graves.…”