Final answer:
Hypothyroidism, associated with symptoms like cold intolerance and altered mental status, is caused by inadequate thyroid hormone production, often necessitating lifelong hormone replacement therapy.
Step-by-step explanation:
Inadequate levels of the hormones produced by the thyroid can cause a condition known as hypothyroidism. Signs and symptoms of this condition include weakness, facial bloating, cold intolerance, lethargy, and altered mental status which can be characterized as reduced mental activity. In contrast, hyperthyroidism results in symptoms like weight loss, excessive sweating, and an increased heart rate. The insufficient production of thyroid hormones, T3 and T4, typically due to a disease of the thyroid gland, pituitary/hypothalamus malfunction or iodine deficiency, can lead to hypothyroidism. This often requires lifelong thyroid hormone replacement therapy for management. The condition of goiter, often associated with iodine deficiency, can exacerbate these symptoms.