The cause of this condition is mainly due to thyroiditis (inflammation of the thyroid), which affects the thyroid cells and prevents them from functioning properly. This is mainly caused by:
• Viral infections
• Hashimoto's thyroiditis (where the immune system attacks the thyroid gland)
Other common causes of hypothyroidism include:
• Congenital defects
• Radiation therapies
• Surgical removal of part or all of the thyroid gland
• Drugs such as amiodarone and lithium (predisposed patients)
• Lack of iodine in the diet
• Damage to the pituitary gland or pituitary gland