Final answer:
Severe or prolonged hypothyroidism in adults can lead to myxoedema, marked by symptoms including thick, dry skin and cognitive issues. It often stems from Hashimoto's thyroiditis and necessitates thyroid hormone replacement therapy to manage symptoms and prevent complications.
Step-by-step explanation:
Severe or prolonged adult hypothyroidism can cause a condition called myxoedema. Hypothyroidism can be due to varied reasons, including diseases affecting the thyroid gland or the pituitary/hypothalamus, or due to a deficiency of iodine. One of the most common causes of hypothyroidism in areas where iodine is sufficient is an autoimmune disorder known as Hashimoto's thyroiditis. This condition is characterized by the body's immune system attacking the thyroid gland, leading to symptoms such as goiter, cold intolerance, muscle weakness, and depression, among others. Hypothyroidism results in numerous symptoms such as weight gain, cold sensitivity, and reduced mental activity, which are treated with thyroid hormone replacement therapy. It's essential to address hypothyroidism effectively, as it can have serious adverse effects on the developing brain in fetuses, leading to cognitive impairments and even deafness.