Understanding the thyroid: Is goitre the same thing as hyperthyroidism?

Surgeons at Nyeri County Referral Hospital perform thyroid surgery on a patient. [Kibata Kihu, Standard]

In the realm of medical challenges, Dr Geoffrey Omolo, a specialist physician and gastroenterologist at Kenyatta National Hospital, faces the complex condition known as hyperthyroidism.

Hyperthyroidism is a condition characterised by an overactive thyroid gland that produces excess thyroid hormones. Common symptoms include palpitations, fatigue, weight loss, heat intolerance, anxiety, and tremors.

The thyroid is a gland that is a butterfly in shape. It is present below the Adam's apple. It has two lobes; right lobe and left lobe. Each lobe lies on either side of the windpipe and a muscle called isthmus joins them.

Dr Omolo says that when the thyroid gland is functioning properly, it maintains the right level of hormones to keep one's metabolism (converting food to energy) operating optimally. It produces replacement hormones as needed.

"The thyroid gland is important for numerous other bodily processes aside from metabolism, such as controlling your heart rate and maintaining body temperature," Dr Omollo adds.

Thyromegaly is a disorder of the thyroid gland. It occurs when the gland enlarges from its standard size. It is commonly known as goiter and may occur due to high levels of thyroid hormone (hyperthyroidism) or due to lack of iodine in the body.

The global prevalence of hyperthyroidism ranges from 0.2 per cent to 1.3 per cent. The most common causes of hyperthyroidism is Graves' disease at 70 per cent and toxic nodular goiter at 16 per cent. Graves' disease is an autoimmune disorder that leads to hyperthyroidism.

Treatments include radioactive iodine, medication, and sometimes surgery.

"First-line treatment is usually antithyroid medication for 12-18 months to control symptoms. Beta-blockers may provide relief in the interim. Radioactive iodine, surgery, or radiofrequency ablation are options for long-term treatment. Untreated hyperthyroidism elevates mortality (death) risk, so timely diagnosis and treatment are important," Dr Omolo explains.

According to Dr Omollo, treatment with anti-thyroid medicine typically lasts 12 to 18 months. After that, the dose may be slowly decreased or stopped if symptoms go away and if blood test results show that thyroid hormone levels have returned to the standard range.

Dr Omollo explains that for some people, anti-thyroid medicine puts hyperthyroidism into long-term remission but other people may find that hyperthyroidism comes back after this treatment.

Toxic nodular goiter is a specific cause of hyperthyroidism due to one or more abnormal nodules or lumps growing in the thyroid gland. Less common causes include subacute thyroiditis, certain medications, and excess iodine intake, which can disrupt proper thyroid gland function.

Toxic nodular goiter is best treated with radioactive iodine therapy or thyroid surgery. However, subacute thyroiditis, which is an inflammatory condition of the thyroid gland causing temporary thyroid dysfunction, often resolves on its own with supportive treatment.

Simple goiter comes in different types; he explains why some type of goiter prevalence is slightly higher in females than males.

"All types of simple goiter are more common in females than males because of the presence of estrogen receptors in the thyroid tissue," he explains.

He stated that pregnancy can also alter a lot of hormones in women. The thyroid can incorrectly process the signals sent by the pituitary gland thus pregnant women have a higher risk for developing a goiter.

The doctor further explains that children can also be born with goiter or develop one later in life.

"A goiter that's present at birth is called a congenital goiter. These can be caused by: a genetic disease that prevents the baby from producing thyroid hormone properly," he adds.

According to Dr Omollo, if the goiter is a sign of another thyroid disease like Graves' disease or Hashimoto's disease, the prognosis depends on the underlying cause of thyroid enlargement.

Dr Omolo says that any nodule that is 4 cm or larger should be removed with thyroid surgery. However, Dr Omolo warns that many patients are incorrectly told nodule removal is unnecessary if not causing symptoms or if benign.