A case of subacute thyroiditis associated with complete occlusion of right coronary artery

Case presentation: A case is a 72-year-old male, and developed fever, sore throat and immigrating neck pain, without shortness of breath (SOB). He showed pulse 96/min, Temp 38.8C, BP 146/90mmHg, respiration and SpO2 normal. Physicals were slight tenderness in thyroid, and laboratory data revealed free T3/T4 10.7pg/mL/5.4ng/dL. He was diagnosed as subacute thyroiditis. ECG showed incomplete right bundle block branch (RBBB) and Holter ECG showed pulse rate 70-144/min and the average was 95.8/min for 24 hours. HbA1c increased from 6.4% to 7.4% for 6 weeks. For the treatment, prednisolone 20mg/day was started and reduced gradually, and thyroid function was normalized. Consecutively, he developed chest discomfort and oppression with unremarkable ECG changes and chest CT showed only the calcification of coronary arteries. Coronary angiography showed occlusion of the right proximal coronary artery (RCA, #2:100%), left anterior descending (LAD, #6:75%, #7:90%). Coronary angioplasty was operated immediately. By placing a drug-eluting stent, RCA was re-opened successfully. His symptoms disappeared, and clinical course was improved. Discussion: Subacute thyroiditis may bring hyperthyroidism and tachycardia, increased metabolism for circulatory system. Then, subacute thyroiditis would give burden and stress for coronary heart function. It is suggested that hyperthyroidism would aggravate the coronary stenosis. We have to consider such complex pathophysiology for the diseased states in the clinical medical practice.