Thyroid Disease Treatment

The thyroid gland is an endocrine organ. Endocrine organs produce hormones that help multiple processes in our body. The thyroid gland produces the hormone thyroxine that essentially controls the metabolic rate of our body and is essential in nearly all bodily functions. It produces this hormone in mass quantities and stores it for future use in a substance called colloid. The release of this hormone is promoted by hormones released by the pituitary gland in the brain, the “headquarters” of the endocrine system.

The thyroid gland is located in the neck. It has a butterfly shape with two lobes lying on either side of our trachea, or windpipe.

When thyroxine levels are too low in the body this is called hypothyroidism. Hypothyroidism is quite common, affecting up to 5% of the general population. The early symptoms of hypothyroidism are varied; common symptoms include cold intolerance, constipation, weight gain, menstrual irregularities, fatigue, itchy skin, brittle fingernails, depression, poor muscle tone, and joint pain. Hypothyroidsim and its possible causes can be identified on blood tests and is treated with thyroid replacement medications. Response to treatment is monitored by symptom control and serial blood tests.

Iodine deficiency is the most common cause of hypothyroidism worldwide, however supplementation of our table salt has limited this cause. In the US, the most common cause is an auto-immune condition called Hashimoto’s thyroiditis. There is no treatment for this condition, however the hormone abnormalities associated are treated as they develop. Some medications such as lithium, amiodarone, and thalidomide have been known to cause hypothyroidism. Exposure to radiation is another important source of hypothyroidisim.

When thyroxine levels are too high in the body this is called hyperthyroidism. Major clinical signs include weight loss (often accompanied by an increased appetite), anxiety, intolerance to heat, hair loss, muscle aches, weakness, fatigue, hyperactivity, irritability, and low blood sugar. Panic attacks, inability to concentrate, and memory problems may also occur. Some patients may experience cardiac arrhythmias; symptoms that are more present in elderly patients.

Ninety percent of hyperthyroidism in the US is caused by an auto-immune condition caused Graves’ disease.

The parathyroid glands are four small glands that lie adjacent to the thyroid gland. They secrete a hormone (parathormone) that controls calcium levels in our body. They occasionally harbor benign growths that cause elevated calcium. These can be surgically excised in a similar approach to thyroid surgery. During thyroid surgery, extra care is taken not to injure these four delicate structures.

The word nodule is not specific. It simply means a growth or mass within the gland. They can be a variety of sizes and can present as a single nodule or multiple nodules within the gland. In order to determine if the nodule is benign or malignant further investigations are necessary. It is important to know that a thyroid gland can have nodules and still have normal function.

The term “goiter” simply refers to the abnormal enlargement of the thyroid gland. It is important to know that the presence of a goiter does not necessarily mean that the thyroid gland is malfunctioning. A goiter can occur in a gland that is producing too much hormone (hyperthyroidism), too little hormone (hypothyroidism), or the correct amount of hormone (euthyroidism). A goiter can be overall enlargement of the gland or a collection of multiple nodules. A large goiter can be clearly visible and cause compressive symptoms of shortness of breath and difficulty swallowing.

An ultrasound exam of the neck is the optimal method for evaluating the structure of the thyroid gland. The ultrasound can determine the location, number, and size of nodules. It also helps in determining the character of the nodules and looks at internal architecture and blood flow. This assessment helps characterize nodules as likely benign, suspicious, or concerning for underlying malignancy. The lymph nodes in the neck can also be examined for any enlargement indicating possible spread of cancer.

Although an ultrasound can provide information regarding the likelihood of malignancy, tissue is required for definitive diagnosis. For nodules greater than 1 cm and ultrasound guided fine needle aspiration (FNA) biopsy acquires cells from within the target nodule for pathological analysis. This FNA biopsy is an office based procedure that requires only local anesthesia. In the vast majority of cases, the FNA is sufficient for diagnosis of cancer. Occasionally, cellular features do not allow for definitive diagnosis. If FNA biopsy results are insufficient, show definitive cancer, or the patient has a visible neck mass causing symptoms of compression surgery is indicated.

Women are six times more likely to develop thyroid nodules and three times more likely to develop thyroid cancer. Although all the reasons are unclear, nodular growth has been shown to be estrogen sensitive. As a result, nodules developing after menopause or in men are more likely to harbor malignancy. Interestingly, a thyroid nodule in a child has a 50% likelihood of malignancy and surgery is often recommended.

Radiation exposure is a significant risk factor for thyroid cancer. Rates of thyroid cancer in children exposed to the Chernobyl nuclear disaster in the Ukraine and Eastern Europe are 10 times the general population. Surveillance for thyroid disease is already underway in Japan in the wake of the tsunami and resulting nuclear accident in 2011. Radiation related cancer is typically a more aggressive variant.

There are three common types of thyroid cancer. Papillary thyroid cancer represents 70% of all thyroid malignancies. It can present in multiple parts of the thyroid simultaneously, so complete surgical excision is recommended.

Follicular carcinoma represents another 25% of thyroid cancers and is treated in a similar fashion. It is more likely to have spread to the lymph nodes at the time of diagnosis, however still carries a good prognosis.

A much more aggressive variant, Medullary carcinoma is fortunately rare, comprising less than 5% of thyroid cancers. It is also treated surgically, however more extensive lymph node dissections are typically performed in addition to gland excision.

Anaplastic carcinoma, a very rare form, presents in the elderly and is uniformly fatal.

For the three most common types of thyroid cancer, total thyroidectomy is the primary treatment. If the cancer is entirely confined to the gland, this is often the only treatment necessary. For a tumor with concerning features, or extraglandular spread, the patient’s endocrinologist may treat with radioactive iodine to destroy any remaining or metastatic thyroid tissue. Overall, the cure rates for papillary and follicular carcinoma are well over 95% with only these methods.

If cancer has spread to local lymph nodes within the neck, it is essential that these are addressed surgically as well. Your surgeon may recommend a neck dissection in addition to thyroidectomy to address these malignant nodes. Interestingly, this local spread does not alter the prognosis of the disease very much and patients still do very well. In the rare cases where an FNA biopsy result is non-diagnostic, your surgeon may recommend a hemi-thyroidectomy. In this surgery, the lobe of the thyroid containing the concerning nodule is removed. While under anesthesia, pathology colleagues examine the nodule and will determine if a malignancy is present. If cancer is identified, your surgeon can then remove the opposite lobe. If the nodule is benign your surgeon may leave the other lobe intact. For most patients, only a half of the thyroid gland is necessary to maintain adequate thyroid function.

Thyroid surgery is performed under general anesthesia. Although minimally invasive options are being developed, an anterior neck incision is still commonly utilized. The surgery is typically 2 to 3 hours and due to the cosmetically sensitive area, closure is performed carefully. An attempt is made to “hide” the incision in existing neck folds and this area typically heals very well.

For a hemi-thyroidectomy, patient may go home the same day. For a total thyroidectomy, most surgeons will admit the patient overnight to monitor calcium levels.

As with most surgeries, there are common risks of bleeding, infection, and those associated with general anesthesia. Infection is very rare postoperatively in thyroid surgery.

Occasionally, the parathyroid glands are affected by the local manipulation of tissue. Following total thyroidectomy approximately 1/3 of patients will have a transient drop in calcium levels and will require supplementation. A dangerous or precipitous drop in calcium is rare, but can occur. As a result, calcium levels are often followed closely in the post-operative period with serial blood tests. Permanently low calcium levels are rare; less than 3%, but present a chronic and difficult problem to treat.

The thyroid gland overlies the recurrent laryngeal nerve, the nerve that controls our vocal folds. In the event this nerve is injured during surgery, vocal fold paralysis can occur. This can lead to a weak, hoarse voice, difficulty swallowing, and shortness of breath with exertion. About 10-20% of patients will have some transient weakness or change in their voice. Only 1% of patients have permanent dysfunction.

The recovery from thyroid surgery is typically quite quick. Normal daily activities can resume quickly with the exception of heavy lifting. Neck soreness and discomfort with swallowing are the most common complaints. Pain medicine, occasionally antibiotics, and supplemental calcium are often provided. If the entire gland has been removed, the patient begins thyroid replacement medication.

Lifelong thyroid replacement is necessary to maintain normal metabolic activity. This is typically done using a once a day dosed thyroid medication. Hormone replacement and the use of radioactive iodine for cancer are typically arranged by your endocrinologist. Typically, regular blood tests including a protein called thyroglobulin are ordered. This protein is made by thyroid tissue and a rising value may be an early sign of cancer recurrence. Imaging is then utilized to determine the site of recurrence.

For patients who underwent hemithyroidectomy, surveillance ultrasound for the alternate side is typically performed annually. Thyroglobulin is only followed in cases of total gland excision.