Inside Danger – Two Cases of Spontaneous Carotid Sinus Syncope in Patients with an Enlarged Thyroid Gland - The 66th Annual Conference of the Israel Heart Society & The Israel Society of Cardiothoracic Surgery

Introduction: Carotid sinus syndrome (CSS) is a rare disease, representing exaggerated response to carotid sinus baroreceptor stimulation. The clinical presentations are dizziness, hypotension, bradycardia or syncope. The common trigger of syncope is external pressure. Internal pressure exerted by a space occupying lesion is uncommon.
We present two patients with CSS associated with an enlarged thyroid of benign and malignant etiology.

Case description: The patients were 81 and 77 years old. They presented with recurrent dizziness, one of them sustaining trauma during a syncopal event. Carotid sinus massage caused a symptomatic 5-second pause in the first, and symptomatic severe bradycardia in the second patient. Head CT was perfomed, and in both patients demonstrated a cervical mass displacing the ipsilateral carotid artery. This turned out to be a right sided goiter and a left lobe anaplastic thyroid carcinoma, respectively. The patient with the goiter underwent resection; however, CSH testing remained positive. A pacemaker was implanted and there were no further episodes. The patient with carcinoma was judged inoperable. A pacemaker was implanted for palliation but he remained hypotensive.

Discussion: CSS is usually dominated by a cardioinhibitory or vasodepressor response. It is commonly caused by external pressure. Not many cases of tumor induced CSS have been reported.
Previously published cases vary with regard to results of surgery and pacemaker implantation.
One may hypothesize that long-term mass effect and advanced age may have caused irreversible structural changes of the carotid sinus resulting in hypersensitivity. This may possibly be related to changes in collagen/elastin ratio with aging;if this is the case, early intervention may prevent a permanent form of the disease.

Conclusion: Two cases of CSS are described, associated with an ipsilateral thyroid mass deforming the carotid artery. Further study is needed to establish causality, and to test the hypothesis that early intervention may prevent a permanent form of the disease.