Causes, Diagnosis and Complications of Multinodular Goiter


Goiter is an enlargement of the thyroid gland. When the thyroid gland have multiple growths or nodules leading to enlargement of the whole thyroid gland, it is termed as multinodular goiter (MNG).

March 9, 2018

Goiter is an enlargement of the thyroid gland. When the thyroid gland have multiple growths or nodules leading to enlargement of the whole thyroid gland, it is termed as multinodular goiter (MNG). Multinodular goiter can be nontoxic or toxic. If normal amounts of thyroid hormone is produced even if in the presence of goiter, it is known as a nontoxic MNG.
If the level of thyroid hormone increases leading to a suppressed TSH, it is known as a toxic MNG. The exact causes of thyroid nodules or multinodular goiters are unknown. However, genetic and environmental factors can be a cause of its occurrence. Multinodular goiters are associated with a higher risk of thyroid cancer. Your doctor will most likely screen you for thyroid cancer if MNG is diagnosed.

Causes of Multinodular Goiter:

The exact causes of thyroid nodules or multinodular goiters are unknown. The development of goiter can be due to a combine effect of genetic and environmental factors such as as diet and drugs. Hashimoto's thyroiditis is an autoimmune disorder and the most common cause of hypothyroidism is associated with a higher risk of thyroid nodules. The nodules combinely lead to MNG forming an irregular appearance in the structure of the thyroid gland. As this process takes many years, multinodular goitre are found as people become older. Iodine deficiency can also cause multinodular goiters which is very rare. 

Diagnosis of Multinodular Goiter:

Diagnosis of multinodular goiter is done based on

Physical examination:

During a routine physical examination or when the patient seeks medical attention for a neck mass or increased size of the neck, a multinodular goiter is often first found.
Initial evaluation includes:

  • a detailed history, specifically focusing on hypo or hyperthyroid symptoms
  • family history of thyroid disease
  • history of head and neck radiation,
  • factors that may be associated with malignancy such as any rapid growth of the neck mass, presence of associated enlarged neck lymph nodes, or new-onset hoarseness.

Physical examination of a MNG is used to determine the size of goiter, the possible extension of the large thyroid in your chest and signs of hyperfunction which include rapid heart rate, irregular heart beats, tremors, nervousness or anxiety.

Blood Test:

With nontoxic MNG, most patients have normal thyroid function. Therefore along with physical examination it is necessary to do some blood test to confirm the diagnosis. This include TSH and free T4 levels.

Ultrasound:

While evaluating a MNG, thyroid ultrasound is also important. It helps determining the size of the goiter more accurately, as well as the size and characteristics of nodules within the goiter. Ultrasound is completely safe as it has no radiation exposure. Ultrasound can also help guide fine needle aspiration (FNA) biopsy of nodules. 

Fine needle aspiration (FNA) biopsy:

If the nodule is over 1 cm in size or nodules that have certain characteristics that could be a sign of cancer, a FNA test is recommended. In this procedure a long, thin needle through your skin and into the thyroid nodule is inserted. Typically ultrasound imaging is used to precisely guide the needle into the nodule. Your doctor uses the needle to remove a sample of cells. The sample is analyzed in the laboratory to look for cancer cells. Looking in to the sample the pathologist will then decide if the nodule is benign or malignant. The procedure is carried out in your doctor's office which takes about 20 minutes and patients can usually return to work or home afterward with no ill effects. Irregular borders, internal tiny calcium deposits, or increased blood flow are certain characteristics that are worrisome for malignancy.

Complications of Multinodular Goiter:

Multinodular goiters which produces excessive of thyroid hormone can be toxic. This causes hyperthyroidism. Hyperthyroidism can be treated with medication that stops the production of thyroid hormone, radioactive iodine, or removal of thyroid gland tissue.
Very large multinodular goiters can also cause compression symptoms, such as trouble breathing or swallowing. Mostly surgery is recommended if your multinodular goiter is large enough to cause these symptoms.
Multinodular goiters do increase your chance of developing thyroid cancer, but they can be treated with medication, radioactive iodine, or surgery depending on the type of diagnosis.