BACKGROUND
The parathyroid glands are usually 4 glands that are located next to the thyroid, 2 on each side. The parathyroid glands regulate calcium levels in the blood by secreting parathyroid hormone (PTH). When calcium levels are low, PTH levels are high and pull calcium out of the bones and prevent calcium from going out in the urine. If the parathyroid glands do not work correctly (hypoparathyroidism), calcium levels are low and can lead to serious problems such as calcium muscle twitching or cramping, seizures and/ or heart problems. Hypoparathyroidism can be caused by damage to the parathyroid glands during thyroid surgery, almost always associated with a total thyroidectomy (surgery to remove the entire thyroid gland).

Postoperative hypoparathyroidism can result from removal of the glands when removing the thyroid (as in thyroid cancer) or by affecting the blood flow to the glands or bruising the glands during surgery. Short-term hypoparathyroidism after surgery due to bruising of the glands is relatively common and usually resolves in 1-2 weeks after surgery. Permanent hypoparathyroidism is rare, associated with 1-2% of total thyroidectomies performed by experienced, high volume thyroid surgeons.

Most studies on postoperative hypoparathyroidism focused on short-term data, meaning less than 30 days after surgery. In this study, the authors analyzed the data of Emergency Department (ED) visits for postoperative hypoparathyroidism up to 2 years after surgery in California’s large population-based cancer and hospital databases, with the goal to comprehend demographic, clinical, and surgical factors associated with these visits.

THE FULL ARTICLE TITLE
Woods AL, et al. Hypoparathyroidism After Total Thyroidectomy: A Population-Based Analysis of California Databases. J Surg Res 2025;310:268-274; doi: 10.1016/j. jss.2025.03.061. PMID: 40327904.

SUMMARY OF THE STUDY
Based on the data from the California Cancer Registry and Health Care Access and Information databases, the authors identified 41,502 patients who had total or near-total thyroid removal surgery for thyroid cancer between 2005 and 2016, with ED visits until 2018. This included patients who visited the ED with the diagnosis of hypoparathyroidism or hypocalcemia within two years of their thyroid surgery.

A total of 588 patients presented to the ED for hypoparathyroidism, with the average time from surgery of 4 days, and with 2/3 of the visits occurring in the first month after surgery. Significant differences were noted based on sex, age, race/ethnicity, socioeconomic status, and the number of lymph nodes removed. The patients with increased risk for ED visits were female sex, Hispanic ethnicity, and having more than 4 lymph nodes removed. In contrast, those in the highest levels of socioeconomic status had a lower incidence of ED visits. Surgeries done in a hospital not accredited by the American College of Surgeons Committee on Cancer had a higher incidence of ED visits for hypocalcemia, though the difference was not statistically significant. Younger patients, between ages 18 and 40, and those in the lowest socioeconomic levels had the highest risk for ED visits.

WHAT ARE THE IMPLICATIONS OF THIS STUDY?
ED visits for hypoparathyroidism post-thyroid surgery for thyroid cancer are not common, but they tend to occur mostly in the first month post-surgery. These data suggest that patients with risk factors (female, age 18-40, having >4 lymph nodes removed) or vulnerable groups (Hispanic, lower socioeconomic status) identified in the study should be monitored closely and managed earlier to avoid ED visits. Recognizing the symptoms early can potentially avoid ED visits with management as an outpatient visit, especially for those at risk for complications.

— Joanna Miragaya, MD

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