Simple Goiter is enlargement of the thyroid gland as a result of stimulation of the thyroid gland by high levels of circulating thyroid stimulating hormone. This high level of TSH might be due to dietary deficiency of iodine as in endemic goiter. Defective hormone synthesis also cause goiter and it accounts for many sporadic goiters. It has stages of development. All stages of simple goiter are far more common in females.
The thyroid gland is an important organ of the endocrine system. It is located at the front of the neck just above where your collarbones meet. The gland makes the hormones that control the way every cell in the body uses energy. This process is called metabolism.
Iodine deficiency is the most common cause of goiter. The body needs iodine to produce thyroid hormone. If you do not have enough iodine in your diet, the thyroid gets larger to try and capture all the iodine it can, so it can make the right amount of thyroid hormone. So, a goiter can be a sign the thyroid is not able to make enough thyroid hormone.
Other causes of goiter include:
- The body’s immune system attacking the thyroid gland (autoimmune problem)
- Certain medicines (lithium, amiodarone)
- Infections (rare)
- Cigarette smoking
- Eating very large amounts of certain foods (soy, peanuts, or vegetables in the broccoli and cabbage family)
- Toxic nodular goiter, an enlarged thyroid gland that has a small growth or many growths called nodules, which produce too much thyroid hormone
Diffuse hyper-plastic goiter
Persistent stimulation by TSH causes diffuse hyperplasia of the thyroid gland. The goiter is soft, diffuse and may become large enough to cause discomfort. In endemic goiter, it usually occurs at puberty when metabolic demands are high, this is reversible if stimulations cease. But, it tends to recur later at times of stress such as pregnancy. As a result of fluctuating stimulation of the thyroid gland, areas of active lobule and inactive lobules will develop. Active lobules become more vascular and hyperplasic until hemorrhage occurs causing necrosis. These necrotic lobules coalesce to form nodules filled with either iodine free colloid or inactive follicles. This the nodular stage of simple goiter. Nodular goiter can be solitary or multinodular. The nodules can be colloid when filled with colloid or cellular. Secondary changes like cystic degeneration, hemorrhage and calcification occur at late stages.
The main symptoms of goiter include:
- A swelling in the front of the neck, just below the Adam’s apple
- feeling of tightness in the throat area
- Hoarseness (scratchy voice)
- Neck vein swelling
- Dizziness when the arms are raised above the head
Other, less common symptoms include:
- Difficulty breathing (shortness of breath)
- Wheezing (due to squeezing of the windpipe)
- Difficulty swallowing (due to squeezing of the esophagus, or “food tube”)
Some people who have a goiter may also have hyperthyroidism, or overactive thyroid. Symptoms of hyperthyroidism can include:
- An increased resting pulse rate
- Rapid heartbeat
- Diarrhea, nausea, vomiting
- Sweating without exercise or increased room temperature
Some people with goiter may also have hypothyroidism, or underactive thyroid. Symptoms of hypothyroidism can include:
Discrete swelling in one lobe with no palpable abnormality else where is called solitary (isolated) nodule. And if there is abnormality else where in the gland it is termed dominant nodule. Nodules are palpable and usually visible. They are smooth, firm and not hard. The Goiter is painless and freely moves with swallowing and usually patients are euthyroid.
- Thyroid function test (T3, T4, TSH) is necessary to exclude hyper or hypothyroidism.
- Chest or thoracic inlet x-rays may show calcification, tracheal deviation and compression.
- Estimation of thyroid antibody titers to exclude auto-immune thyroiditis.
Prevention and treatment
In endemic areas the incidence of goiter can be significantly reduced by the introduction of iodized salt. In early stages, a hyper-plastic goiter may regress if thyroxin is given in a dose of 0.1mg daily for few months. The nodular stages of simple goiter are irreversible. But most of the patients are asymptomatic and do not require operation.
Operation might be indicated
- On cosmetic grounds
- Tracheal compression and
- When malignancy cannot be excluded
The options of surgical treatment are
- Near total thyroidectomy
- Subtotal thyroidectomy