Goiter

What is Goiter?

Goiter is a condition where the thyroid gland – an important organ in the neck – becomes larger than normal. You can determine if you have a goiter by touching your neck, by looking at it, or through a special picture of your body (what doctors call an “imaging study”).

The healthy size of a thyroid gland is typically around 4 to 4.8 cm when measured from front to back, 1 to 1.8 cm from left to right, and 0.8 to 1.6 cm from top to bottom. In other words, the healthy volume of a thyroid is about 7 to 10 mL, which weighs about 10-20 grams. Keep in mind, your thyroid might be bigger based on your age and how big your body is. Men tend to have larger thyroids than women, and people who consume more iodine tend to have smaller thyroids.

There are many reasons your thyroid could grow larger. Sometimes, it’s natural – for instance, during teenage years or pregnancy. The goiter can happen alongside normal thyroid function, too much thyroid function (hyperthyroidism), or too little thyroid function (hypothyroidism). The larger thyroid could be evenly enlarged, have bumps, or multiple bumps. Usually, as the thyroid grows, it stretches forward in the neck, as the muscles, fat, and skin on the front of the neck aren’t very strong or restrictive. Usually, the term “goiter” is used to describe growths in this area. If the thyroid grows downward instead, and enters the area below the neck and into the chest area (the thoracic inlet), it’s called a substernal or retrosternal goiter.

What Causes Goiter?

There are several reasons why someone might develop a goiter, which is a swelling of the thyroid gland in your neck. One common cause is a lack of iodine – this is often reported in places that don’t have a public health program to prevent iodine deficiency. When it happens due to iodine deficiency, it’s known as endemic goiter.

Inflammation due to various types of thyroid disorders can also cause your thyroid gland to swell, leading to goiter. Some of these disorders include autoimmune thyroiditis, postpartum thyroiditis (which occurs after giving birth), silent thyroiditis, radiation thyroiditis, subacute thyroiditis, and suppurative thyroiditis.

When the swelling is because of inflammation, it doesn’t usually last very long – it decreases once the inflammation goes away. In this context, the term ‘goiter’ isn’t typically used to describe the disorder itself, but it’s recognized as one of the signs of an inflamed thyroid gland.

Certain diseases that lead to an overactive thyroid, or hyperthyroidism, such as Graves’ disease, toxic nodular goiter, and toxic multinodular goiter, can also result in a goiter. Goiter can occur as one or multiple nodules, known as nodular goiter or non-toxic multinodular goiter. In these cases, the enlarged thyroid is associated with normal thyroid function, which is also known as euthyroidism.

Other possible causes can include thyroid cancer or other diseases that cause granules or infiltrates to form in the thyroid gland.

Risk Factors and Frequency for Goiter

Goiters, or enlarged thyroids, are primarily caused by a lack of iodine and affect approximately 2.2 billion people worldwide. How severely deficient a person is in iodine can determine the likelihood of developing a goiter. Those mildly lacking iodine have a 5% to 20% chance of getting goiter, with the odds rising to 20% to 30% with moderate deficiency and over 30% with severe deficiency.

Despite iodine use, there’s been a rise in thyroid nodules, which may be due to enhanced detection through more frequent ultrasound screenings and radiological imaging. But, improvements in technology and screening practices are not the only reasons for the increase; obesity, insulin resistance, and metabolic syndrome may also contribute to a higher occurrence of goiter.

Current ultrasound technology can discover even the smallest nodules, revealing that the incidence of thyroid nodules in adults sits between 60% and 70%. Women are about four times more likely than men to develop goiter, but it’s important to note that all races are equally at risk.

• Goiters are mainly caused by a lack of iodine, affecting around 2.2 billion people.
• The chance of developing a goiter varies with the severity of iodine deficiency: 5%-20% with mild, 20%-30% with moderate, and over 30% with severe deficiency.
• There’s been an increase in thyroid nodules, potentially due to more sophisticated detection methods or health conditions like obesity, insulin resistance, and metabolic syndrome.
• Ultrasound technology can detect small nodules, accounting for a 60%-70% incidence rate in adults.
• Women are four times more likely than men to develop goiter.
• Goiter affects all races equally.

Signs and Symptoms of Goiter

A goiter is a condition that causes enlargement of the thyroid gland. This change in size of the thyroid can be slow or rapid. Slow enlargement often does not cause any symptoms, and people might only notice the aesthetic change. Rapid growth, however, can be due to internal bleeding in the thyroid, inflammation, or cancer. This rapid enlargement can lead to lower neck pain and a feeling of stuffiness, making it difficult to breathe or swallow. Obstruction can also lead to hoarseness, and rarely, it can affect nerve or blood vessel function.

Doctors need to know a patient’s medical and family history regarding thyroid diseases, where the patient has spent most of their life, their iodine levels, and any exposure to radiation. They will also ask about symptoms related to feeling pressure on the throat, hoarseness, and coughing. The appearance of the goiter and any possible discomfort it causes should also be discussed.

The physical examination of the thyroid involves the doctor checking for signs of abnormal thyroid function. They inspect and feel the thyroid on the neck, and then interpret the results based on size, texture, tenderness, and the presence of any nodules. They will also ask the patient to swallow during this process to facilitate palpation. If the lower border of the thyroid can’t be palpated while standing, they will check it in a lying down position. If they suspect goiter under the breastbone, they will use the Pemberton’s sign test by asking the patient to lift their arms for at least one minute. Facial congestion, neck vein bulging, hoarseness, or trouble breathing indicate a positive Pemberton sign, consequently confirming goiter under the breastbone. The last steps are to determine the size of the thyroid by palpation and examine the rest of the neck for enlarged lymph nodes or other masses.

Testing for Goiter

Goiters, which are enlarged thyroids, can occur even if someone has a normal thyroid (euthyroid), overactive thyroid (hyperthyroid), or underactive thyroid (hypothyroid). Most people with a simple goiter (a general enlargement of the thyroid without any bumps) have a normal thyroid. This is the same for those with a single thyroid bump and multiple thyroid bumps (multinodular goiters). The presence of these bumps, known as nodular goiters, may either cause no symptoms and come with normal TSH levels (a hormone that regulates thyroid function), or be connected with hyperthyroid symptoms and show decreased TSH levels.

Often, a goiter is found during a physical exam, or as an unexpected discovery during an imaging test like a carotid Doppler, neck CT, cervical MRI, or a PET-CT scan. Medical practitioners perform imaging tests and biochemical testing in patients with simple goiters to evaluate the size, extent of the goiter, its relationship with surrounding anatomy, gauge any compression, and to check for the presence of nodular goiters. If there’s a cold nodule (non-functioning thyroid lumps), it may need to be sampled with a fine needle aspiration biopsy.

To assess a patient’s thyroid status, the first step is to measure TSH levels. Other tests like Free T4, total T3, antithyroglobulin, and thyroid peroxidase antibodies can add to the evaluation. An ultrasound of the thyroid is performed next to assess the size of the thyroid gland, note any nodules, the extent of thyroid enlargement, relationship with surrounding structure, and to check for any suspicious findings.

Ultrasound results that show features like decreased echo, microcalcification (tiny calcium deposits), irregular boundaries, larger height than width, a protrusion from the nodule’s capsule, and size greater than 1 cm make nodules more suspicious and these ones, if the size is 1 cm or larger, may need a fine-needle aspiration biopsy. In those cases that show cancerous features, the next step is usually surgery. Other imaging tests like a chest x-ray, computerized tomography, or magnetic resonance imaging may be needed if there are symptoms suggesting compression to better check for any changes to the trachea, airway compression, and growth beyond the sternum. If difficulty in swallowing (dysphagia) is present, pulmonary function tests and rarely barium swallow studies are used.

Treatment Options for Goiter

The main goal of treating a goiter, which is an enlargement of the thyroid gland, is to reduce discomfort or symptoms and to normalize thyroid hormone levels. Generally, people with nontoxic goiters have normal or slightly reduced thyroid hormone levels. If thyroid hormone levels are low, treatment would include taking thyroid hormone medication. If the goiter is toxic, meaning it’s producing too much thyroid hormone, treatments would aim to reduce both the size of the thyroid gland and the amount of thyroid hormone in the body.

Non-toxic goiters are usually either monitored without treatment or surgically removed. The use of hormone-suppressing medication to treat this condition is not commonly recommended now due to its limited effectiveness and potential side effects, such as heart rhythm issues, decreased bone density, and overactive thyroid.

Doctors typically watch for any changes in the goiter through check-ups, blood tests and ultrasound scans. Some goiters can get smaller on their own over time. However, if the goiter grows, causing uncomfortable symptoms like a feeling of choking, difficulty swallowing, or a change in voice, or if it’s affecting one’s appearance, surgery to remove the thyroid gland can be an option. If surgery isn’t possible due to personal preference or health-related reasons, radioiodine therapy, a treatment that uses a radioactive form of iodine to reduce the size of the thyroid gland, can be an alternative.

The treatment for toxic goiters may involve surgery, radioiodine therapy, or antithyroid drugs, which can reduce the production of thyroid hormone. Symptoms caused by excessive thyroid hormone, such as rapid heart rate and anxiety, can be managed with a type of medication called beta-blockers. Beta-blockers are also used for their heart-protective effects.

In cases where the excessive thyroid hormone levels are not causing symptoms (known as subclinical hyperthyroidism), treatment decisions would be based on factors like the person’s age, the cause of the goiter, and other health conditions. Radioiodine therapy is usually the preferred treatment.

Antithyroid drugs, although effective in reducing thyroid hormone levels, often have to be continued indefinitely, as the overactive thyroid condition tends to come back once the medication is stopped. Therefore, these drugs are usually used in people who are preparing for surgery or radioiodine therapy or in those who can’t or don’t wish to undergo these treatments.

Surgery can be considered if the goiter is causing blockage, is very large, cancer is suspected or confirmed, or if there’s an immediate need to control hyperthyroid symptoms. After surgery, thyroid hormone replacement treatment might be needed to ensure the body has enough thyroid hormone.

Radioactive iodine therapy uses a type of iodine that emits radiation to decrease the size and activity of the thyroid gland. This therapy may require several attempts to successfully regulate the thyroid hormone levels. Pregnant and breastfeeding women or women who plan on getting pregnant in the next six months should not receive this treatment.

What else can Goiter be?

The following is a list of health conditions that might be considered due to their shared symptoms:

• Branchial cleft cyst
• Carotid artery aneurysm
• Lymphatic malformation (also known as cystic hygroma)
• Fibroma
• Lipoma
• Lymphadenopathy (this is quite common)
• Parathyroid adenoma
• Parathyroid cyst
• Pseudogoiter (also quite common)
• Thyroglossal duct cyst
• Thyroid abscess
• Thyroid lymphoma

It’s important that physicians consider these possibilities carefully while diagnosing.

What to expect with Goiter

A simple goiter generally has a good possible outcome. However, if the thyroid keeps growing it could press on surrounding parts and may make breathing or swallowing hard, and cause hoarseness. There’s an important need to tell the difference between harmless and harmful causes of thyroid enlargement. If the goiter keeps growing, surgery could be an option to consider. If the goiter shows up because of another thyroid issue like Graves disease or Hashimoto thyroiditis, the possible outcome really depends on what’s causing the thyroid to expand.

Possible Complications When Diagnosed with Goiter

Goiter can lead to various health conditions like hypothyroidism, hyperthyroidism, additional goiter growth, retrosternal extension (growth towards the chest), nodule development, and even the discovery of thyroid cancer. But, these are not considered complications of the goiter itself, rather they are just different outcomes or issues that may come up due to having a goiter.

However, complications can still occur with simple goiter. These include:

• The collapsing of the trachea due to pressure from the enlarged thyroid (tracheomalacia)
• An incident called the Iodo-Basedow phenomenon, where a person develops hyperthyroidism because they’ve consumed too much iodine
• Bleeding or tissue death within a thyroid nodule

Preventing Goiter

To avoid developing a condition called goiter, which is an enlargement of the thyroid gland in your neck, it’s important to take in the right amount of iodine each day. For kids between 2 and 5 years old, they should get 90 micrograms of iodine each day. Kids from 6 to 9 years old need a little more, around 120 micrograms each day. Once kids hit 10 years old and through adult age, the daily needed amount is 150 micrograms.

During pregnancy, the body needs more iodine, about 250 micrograms each day. Women who are breastfeeding have an increased need as well since they need to provide enough iodine in their breast milk, so an extra 50 micrograms each day is recommended.

Goiter can also be prevented by avoiding certain foods known as goitrogens, which can interfere with how our body uses iodine. Similarly, reducing exposure to radiation can also help prevent goiter.