Although treatment with dexamethasone before thyroid surgery does not significantly prevent hypoparathyroidism and excess calcium following the procedure, the frequency of hypoparathyroidism after surgery tended to be lower with dexamethasone treatment, a clinical study has found.
Results of the study, “Preventive Effect of Dexamethasone Therapy on the Transient Hypoparathyroidism through Total Thyroidectomy,” were published in the Iranian Journal of Otorhinolaryngology.
Post-surgical hypoparathyroidism is a common temporary complication in patients who undergo thyroid removal surgery. The most common cause of hypoparathyroidism is injury to the parathyroid glands during surgical removal of the thyroid, which can occur in a wide range of 6.9% to 46% of the patients who undergo this type of surgery.
During thyroidectomy — the surgical removal of all or part of the thyroid — there is risk of injury or accidental removal of the surrounding tissues, including the parathyroid glands. This may increase the risk of hypoparathyroidism, caused by a shortage in parathyroid hormone (PTH), and consequent decrease in the blood levels of phosphorus and calcium (hypocalcemia).
Most times, hypoparathyroidism due to thyroid surgery lasts only days, even though in more severe cases the condition can become permanent.
Prophylactic (preventive) treatment with oral calcium and vitamin D can be used. But in some patients this may lead to an excess in calcium, or hypercalcemia, which can lead to a number of other negative effects like weakening of the bones, kidney stones, or even brain or heart problems.
Several clinical trials have indicated that pre-operative treatment with glucocorticoid drugs — potent anti-inflammatory medicines — can reduce inflammation and attenuate complications following surgery.
For thyroid surgery, dexamethasone in particular has been found safe and effective to reduce post-operative nausea, vomiting, and pain.
Now, researchers conducted a randomized Phase 2 clinical trial (IRCT2017011329726N3) to investigate whether pre-operative dexamethasone could lessen transient hypoparathyroidism caused by total thyroidectomy.
The study was conducted on 128 patients who underwent surgery from March 2014 to April 2015 in Alzahra Hospital, Iran. Patients were randomly assigned to receive an 8 mg intravenous injection of dexamethasone (45 patients) 45 min before surgery start or no treatment with dexamethasone (83 patients). After surgery, all patients were evaluated for clinical and laboratory signs of hypocalcemia.
A total of 50 (39.1%) patients developed hypocalcaemia after surgery, and this happened more frequently in the control (untreated group) (68%) compared to the dexamethasone group (32%); however, this difference was not statistically significant.
In agreement with these results, blood tests for PTH and calcium levels were not significantly different between those receiving dexamethasone and the untreated subjects.
However, blood levels of phosphorus were significantly higher following surgery in those treated with pre-operative dexamethasone.
“In the present study, post-operative transient biochemical hypoparathyroidism and hypocalcemia did not occur more often in the control group, compared to the dexamethasone group. However, a non-significant lower occurrence rate in post-operative symptomatic hypocalcemia was observed in the dexamethasone group when compared with the control group,” researchers wrote.
In light of these results, team believes that “precise care during surgery is more important than dexamethasone administration.”
However, they also underline that it “is essential to conduct future studies with validated means for better results.”