Symptomatic Hypothyroidism after Aortic Valve Replacement in an Octogenarian

Abstract

Surgical stress is closely associated with the activity of the thyroid hormone. Although many patients undergoing cardiac surgery revealed markedly low triiodothyronine (T3), few patients showed symptomatic hypothyroidism. This condition is generally recognized as “non thyroidal illness (NTI) ” which is characterized by a low T3 level, despite the normal function of hypothalamus-pituitary-thyroid system. NTI is generally considered as one of the biological defense mechanisms rather than a pathological condition, eliminating the requirement of medical intervention. Even if low T3 is observed in blood biochemical examination after open heart surgery, a cautious interpretation is required. We report an elderly case presenting severe fatigue and mild disorientation accompanied by significantly low thyroid hormone after aortic valve replacement. The morbidity was remarkably improved with medical treatment, suggesting hypothyroidism after cardiac surgery.