Final answer:
A thyroidectomy would lead to hypothyroidism, necessitating lifelong thyroid hormone replacement therapy to maintain normal bodily functions, with careful monitoring required to avoid symptoms of under- or over-replacement.
Step-by-step explanation:
A thyroidectomy—the surgical removal of the thyroid gland—would result in the body no longer being able to naturally produce thyroid hormones, which include T3 (triiodothyronine) and T4 (thyroxine). The primary consequence of this is hypothyroidism, a condition characterized by a low metabolic rate, weight gain, cold sensitivity, reduced mental activity, and other symptoms related to a general slowing of bodily functions. After a thyroidectomy, patients typically require lifelong supplementation with synthetic thyroid hormone to maintain normal metabolic function and prevent the symptoms of hypothyroidism. The dosage of replacement thyroid hormone must be carefully monitored and adjusted to ensure that it adequately mimics natural thyroid function without causing adverse effects.
Without careful monitoring, patients might experience symptoms of either under- or over-replacement of thyroid hormones, such as heart problems, osteoporosis, or infertility. Contrarily, in conditions like Graves' disease (a form of hyperthyroidism), the thyroid gland is overactive, and removal or partial removal of the thyroid gland can help restore balance.