Acute Thyroiditis Complicating Parathyroidectomy

Cardiac Complications Post Parathyroidectomy: A Systematic Review

Parathyroidectomy (PTX) treats hyperparathyroidism, but it can lead to significant cardiac complications. This systematic review analyses the incidence, types, risk factors, pathophysiological mechanisms, and management strategies of cardiac complications following PTX. Following PRISMA guidelines, a systematic search of PubMed and Europe PMC up to May 2024 included 62 studies. Cardiac complications identified included early and delayed reversible cardiac failure, tachyarrhythmias (such as atrial fibrillation and ventricular tachyarrhythmia), chest pain, myocardial infarction mimic, hypotension, and other two rare complications. Rapid calcium level changes and thyrotoxicosis post-surgery were the significant contributors to the complications. Vigilant monitoring and management are essential for favourable outcomes post-PTX. Comprehensive preoperative evaluation, meticulous intraoperative monitoring, and tailored postoperative care are crucial. Further research is needed to refine management protocols and improve patient safety.

Thyroiditis After Parathyroidectomy

Various clinical manifestations of thyroiditis after parathyroidectomy have been reported in the literature, ranging from mild symptoms to tachyarrhythmias and myocardial infarction. We report 2 cases of post-parathyroidectomy thyroiditis. Both patients had primary hyperparathyroidism and underwent parathyroidectomy for a solitary parathyroid adenoma. They subsequently developed symptoms of hyperthyroidism, including palpitations and heat intolerance. Laboratory investigations demonstrated a suppressed TSH level with elevated free T4 levels and low uptake on thyroid radioiodine scan, confirming the diagnosis of thyroiditis. The patients were managed conservatively, and their symptoms gradually resolved with normalization of thyroid hormone levels. A review of 27 cases reported to date reveals that this condition is mostly attributed to manipulation of the thyroid during parathyroid surgery. It occurs more frequently in patients who undergo 4-gland parathyroidectomy for secondary or tertiary hyperthyroidism and is self-limited within a few weeks. The case reports highlight the importance of recognizing thyroiditis as a potentially underrecognized complication of parathyroid surgery. Further research is warranted to better understand the underlying pathophysiology and to establish potential risk factors for its development post-parathyroidectomy.

Acute thyrotoxicosis secondary to destructive thyroiditis associated with cardiac catheterization contrast dye

BACKGROUND

Thyrotoxicosis caused by destructive thyroiditis is self-limited and results from the subacute release of preformed thyroid hormone. Common etiologies include painful subacute thyroiditis and silent (painless) subacute thyroiditis (including postpartum thyroiditis, amiodarone-associated destructive thyroiditis, and lithium-associated thyroiditis). Thyrotoxicosis commonly evolves slowly over a matter of weeks.

PATIENT FINDINGS

We report a unique case of severe thyrotoxicosis caused by acute- onset painful destructive thyroiditis in a patient who received large amounts of nonionic contrast dye Hexabrix® for cardiac catheterization. The results of thyroid function and physical examination were normal before the catheterization.

SUMMARY

The acute onset of severe thyroid pain, rapid increase in serum Free Thyroxine Index, and thyroglobulin concentrations with a triiodothyronine to free thyroxine index ratio of < 20 to 1 were compatible with an acute onset destructive thyroiditis, likely related to direct toxicity from the iodinated contrast material.

CONCLUSIONS

In light of the large number of patients who receive these contrast agents during cardiac catheterization, clinicians should be advised of this potentially serious complication, particularly in the setting of unstable cardiac disease.