The thyroid gland is critical for regulating the body’s metabolic rate. An underactive thyroid (also called hypothyroidism) occurs when the thyroid gland doesn’t create and release enough thyroid hormone into the bloodstream. There can be various causes and symptoms.
What does the thyroid gland do?
The thyroid gland is a small, butterfly-shaped organ located in the front lower part of the neck, just under the voice box (larynx). Via the production and release of hormones, the thyroid controls how the body’s cells use energy. It regulates how the overall metabolism functions, including the body’s temperature, heartbeat, and how well it burns calories.
What is hypothyroidism?
The thyroid can malfunction in different ways. Hyperthyroidism (overactive thyroid) occurs when the gland releases too many hormones, thus accelerating the body’s metabolism. On the other hand, hypothyroidism (underactive thyroid) occurs when the gland releases too few hormones, thus slowing the body’s metabolism.
Hypothyroidism is most prevalent among women and people over 50 years of age.
Causes of hypothyroidism.
Hypothyroidism usually involves inflammation of the thyroid gland (thyroiditis). This can be linked to, or caused by:
- Autoimmune disease.
- Pregnancy (either during or postpartum).
- Respiratory infections.
- Congenital abnormalities.
- Total or partial removal of the thyroid gland.
- Lithium, amiodarone, or chemotherapy.
- Radiation cancer treatment.
- Radioactive iodine-based treatment to correct hyperthyroidism.
- Damage to the pituitary gland (tumour, radiation, surgery).
- Rare disorders such as amyloidosis, sarcoidosis, or hemochromatosis.
Symptoms of hypothyroidism.
- Fatigue is the most common symptom of hypothyroidism. An underactive thyroid makes the metabolism slow down, thus making a person feel tired.
- Weight gain. An underactive metabolism does not burn off many calories, so these accumulate.
- Feeling cold. The body produces warmth as it burns calories. A metabolism that burns few calories produces little warmth.
- Hair loss. An imbalance of thyroid hormones can lead to hair follicles not regenerating.
- Pain in muscles and joints. Fatigue brings with it a feeling of weakness, and prolonged inactivity will reduce the strength of muscles and joints.
- Dry skin. As skin cells do not regenerate appropriately, they become itchy, dry, and flaky.
- Depression. A hormonal imbalance has repercussions on a person’s mood. For example, pregnant women experience changing levels of hormones, and if these are not well-adjusted it may lead to post-partum depression.
- Problems with memory and concentration. Treating an underactive thyroid improves memory and concentration.
- Constipation and poor rectal function. Thyroid hormones help regulate digestion.
- Irregular menstruation. Periods may become more irregular with abundant bleeding.