Understanding thyroid goitre
When the thyroid becomes enlarged, it becomes what is known as a goitre. In this article, consultant ENT surgeon Mr Imad Amer discusses the causes of goitres, the signs of them, and how they can be treated.
Goitres occur due to thyroidal swelling. The thyroid is a gland in the neck that produces the thyroxine and triiodothyronine hormones, which play a role in regulating metabolism, body temperature, mood, digestion, and heart rate. Sometimes the thyroid can be overproducing (hyperthyroidism) or underproducing (hypothyroidism) its hormones due to dysfunction that can stem from many possible causes, which can range from mild to quite severe.
What are the types of goitres?
The level of concern merited for a goitre will depend on the reason for the thyroid swelling, and thus there are different classifications of goitre:
- A simple goitre, where the entire thyroid swells, feeling smooth to the touch
- A nodular goitre, where a nodule forms on the thyroid, making it feel lumpy to the touch
- A multinodular goitre, where many nodules form within the thyroid, but they may not be noticeable with sight or touch, and may only be discovered during an examination or scan
- A toxic goitre occurs during hyperthyroidism
- A nontoxic goitre occurs when the thyroid is functioning as normal (euthyroid)
What causes goitres?
A goitre developing is most common with those who have a metabolic condition like obesity or diabetes, due to the hormonal imbalances associated with them. Goitres are also more common for patients who have undergone prior radiation therapy or exposure, and for those who have a family history of thyroid diseases and illnesses.
Goitres can be triggered by:
- Iodine deficiency, as iodine is a key component in the production of the thyroid hormones. When there it is not sufficient levels of iodine in the body, the thyroid tries to compensate by becoming larger.
- Autoimmune diseases such as Graves’ disease or Hashimoto’s disease, where the immune system starts attacking the thyroid
- Thyroid cancer
- Pregnancy
- Thyroiditis
But sometimes, nontoxic goitres may just develop with for no discernible reason, even as the thyroid is functioning perfectly normally.
How are goitres diagnosed?
To diagnose goitres, doctors will typically start with a physical examination, where they will see or feel the swollen thyroid in the throat. Further testing that may be conducted includes blood tests to evaluate the levels of hormones in the blood, scans such as ultrasounds and CT scans, and the extraction of a tissue sample for laboratory analysis called a biopsy.
A specialised imaging test called a thyroid uptake and scan provides information about the size and functionality of the thyroid. The test involves injecting a small amount of radioactive iodine into a vein, which is then absorbed by the thyroid. A probe then measures the thyroid's radioactivity to assess whether it is over- or underproductive.
How are goitres treated?
Some goitres, such as most simple goitres, may go away with some time without needing medical intervention -- however, it is still advised to keep an eye on it to ensure there are no changes such as it getting bigger.
For other goitres, they can be treated as their triggering factor is addressed. For example, an iodine deficiency can be helped by incorporating more iodine into the diet.
Medications used to treat goitres include thyroid hormone supplements such as levothyroxine for hypothyroidism, or thyroid suppressors like methimazole and propylthiouracil for hyperthyroidism. Another alternative for hyperthyroidism is radioactive iodine therapy, where radioactive iodine is taken orally daily to attack thyroid cells, slowing the thyroid’s productivity and effectively shrinking it. After undergoing radioactive iodine therapy, the patient will likely need to take thyroid hormone supplements for the rest of their life, as they thyroid function will be permanently impaired.
If the thyroid is inflamed with no obvious agitator, then corticosteroids can be used to reduce swelling.
If all conservative treatment options are ineffective and the patient is experiencing serious issues with breathing and swallowing, or if the thyroid has cancer, then the doctor may recommend removing the thyroid in a procedure called a thyroidectomy. Following the surgery, the patient will also need to take thyroid hormone supplements for the rest of their life.