Thyroid

Thyroid hormone is used in two situations:

• to replace the function of the thyroid gland, which is no longer functioning normally (“replacement therapy”) and
• to prevent further growth of thyroid tissue (“suppression therapy”). Suppression therapy is used primarily in patients with thyroid cancer to prevent recurrence or progression of their cancer.

THYROID HORMONE REPLACEMENT THERAPY

Many people have a thyroid gland that cannot make enough thyroid hormone for the body’s needs. This is called Hypothyroidism and may be caused by a non-functioning thyroid gland (for example Hashimoto’s disease), by destruction of thyroid gland by surgery or radiation treatment or by a non-functioning pituitary gland. Hypothyroidism, is the most common reason for needing thyroid hormone replacement.

The goal of thyroid hormone treatment is to closely replicate normal thyroid functioning. Pure, synthetic thyroxine (T4) works in the same way as a patient’s own thyroid hormone would. Thyroid hormone is necessary for the health of all the cells in the body. Therefore, taking thyroid hormone is different from taking other medications, because its job is to replace a hormone that is missing. The only safety concerns about taking thyroid hormone are taking too much or too little. Your thyroid function will be monitored by your physician to make sure this does not happen.

1.) WHY DO I NEED THYROID HORMONE PILLS?

Hypothyroidism is the most common reason for needing thyroid hormone replacement. Pure synthetic thyroxine (T4), taken once daily by mouth, successfully treats the symptoms of hypothyroidism in most patients.

2.) HOW IS THE DOSE OF THYROID HORMONE CHOSEN?

When someone is first started on thyroid hormone the initial dose is carefully selected based on information such as a person’s weight, age, and other medical conditions. The dose will then need to be adjusted by a physician to keep the thyroid function normal. The physician will make sure the thyroid hormone dose is correct by performing a physical examination and checking TSH levels.

There are several brand names of thyroid hormone available. Although these all contain the same synthetic T4, there are different inactive ingredients in each of the brand names. In general, it is best for you to stay on the same brand name. If a change in brand name is unavoidable, you should be sure your physician is aware of the change, so that your thyroid function can be re-checked. If your pharmacy plan changes your thyroid hormone to a generic preparation, it is important for you to inform your physician.

Thyroid, Basal Metabolic Rate (BMR) and Weight

It has been appreciated for a very long time that there is a complex relationship between thyroid disease, body weight and metabolism. Thyroid hormone regulates metabolism in both animals and humans.

Metabolism is determined by measuring the amount of oxygen used by the body over a specific amount of time. If the measurement is made at rest, it is known as the basal metabolic rate (BMR). Measurement of the BMR was one of the earliest tests used to assess a patient’s thyroid status. Patients whose thyroid glands were not working were found to have low BMR, and those with overactive thyroid glands had high BMR.

Later studies linked these observations with measurements of thyroid hormone levels and showed that low thyroid hormone levels were associated with low BMR and high thyroid hormone levels were associated with high BMR. Most physicians no longer use BMR due to the complexity in doing the test and because the BMR is affected by many factors other than the thyroid state.

Differences in BMR is associated with changes in energy balance. Energy balance reflects the difference between the amount of calories one eats and the amount of calories the body uses.

If a high BMR is induced by the administration of drugs, people often have a negative energy balance which leads to weight loss. Based on such studies many people have concluded that changes in thyroid hormone levels, which lead to changes in BMR, should also cause changes in energy balance and similar changes in body weight.

The functioning of the skin depends on the general health of the body and is under the control of hormones especially thyroid.  Hair growth, grease glands (sebaceous glands that produce grease or sebum) are affected by the thyroid. The actual thickness of the skin also depends on thyroid function. The skin manifestations of thyroid disease can present as non-specific signs secondary to thyroid imbalances such as hyperthyroidism (Graves’ disease) and hypothyroidism (Hashimoto’s thyroiditis), or can appear in association with other autoimmune diseases.

How common are thyroid problems in older people?

If thyroid gland is hyperfunctioning it is called as Hyperthyroidism and if thyroid gland is underfunctioning it is called as state of Hypothyroidism. Thyroid underfunction is about twice as common as overfunction. Thyroid problems are more common in older women than in men. Thyroid gland enlargement can be diffuse or nodular. Occasionally thyroid enlargements are calcified thyroid nodules. Although these calcified nodules may in fact be benign, it is generally advisable to biopsy them to determine their exact cause.

Symptoms of thyroid gland dysfunction

Symptoms of hyperthyroidism and hypothyroidism are similar to those in younger patients. It is not uncommon for both hyperthyroidism  to  manifest in subtle ways in older patients, often masquerading as diseases of the bowel or heart or a disorder of the nervous system like history of  tremors,weight loss, palpitations, osteoporosis, depression and psychiatric manifestations. Unlike symptoms of hyperthyroidism, the symptoms of hypothyroidism are very non-specific in all patients, even more so in the older patient. Memory loss or a decrease in cognitive functioning, often attributed to advancing age, may be the only symptoms of hypothyroidism present.  Hypothyroidism usually presents with history of lethargy, change in voice, weight gain, cold intolerance, constipation.

Clues to the possibility of hypothyroidism include a positive family history of thyroid disease, past treatment for hyperthyroidism, or a history of extensive surgery and/or radiotherapy to the neck

There are many different names you might find for the autoimmune eye condition that is often seen with thyroid disease, including:

• Thyroid Eye Disease, sometimes abbreviated as TED
• Graves’ Opthamolopathy
• Thyroid-associated orbitopathy (TAO)
• Grave’s orbitopathy

Thyroid Eye Disease is an autoimmune eye condition that, while separate from thyroid disease, is often seen in conjunction with Graves’ Disease. The condition, however, is seen in people with no other evidence of thyroid dysfunction, and occasionally in patients who have Hashimoto’s Disease. Most thyroid patients, however, will not develop thyroid eye disease, and if so, only mildly so.

Signs and Symptoms of Thyroid Eye Disease

• Pain in the eyes, pain when looking up, down or sideways
• Dryness, itching, dry eyes, difficulty wearing contact lenses
• Inflammation and swelling of the eye, and its surrounding tissues
• Swelling in the orbital tissues which causes the eye to be pushed forward — referred to as exophthalmos — which can make Thyroid Eye Disease sufferers appear to have a wide-eyed or bulging stare.

Thyroid is an organ in the body with most diverse biology among tumors. Even the best of the pathologists cannot say that it is cancer or not when thyroid tests are done.

Sometimes, in presence of a nodule and when test results are not accurate, operations are needed to confirm the diagnosis.

These operations can be of following types-

1. Open biopsy- A small part of nodule or thyroid tumor is taken out by an operation.
2. Nodulectomy- Some surgeons who are not expert in thyroid surgery may perform nodulectomy which is removal of nodule only. However, this type of surgery should not be performed.
3. Thyroid Lobectomy- Thyroid has two lobes; right and left. If nodule is in one lobe, that lobe is removed and send for tests. This removal of a lobe is known as lobectomy.
4. Hemithyroidectomy- When one lobe of thyroid is removed along with its connecting part (isthmus) with the other lobe and also the removal of pyramidal lobe, it is known as hemithyroidectomy.. Lymph node biopsy- Sometimes, thyroid nodules are associated with enlarged lymph nodes on side of the neck. When diagnosis is not confirmed, then the lymph node may be removed by biopsy and send for testing.

   The tumor piece of thyroid or lymph node which is removed is send for histopathology. This histopathology report confirms the diagnosis and then appropriate action can be taken. Example, if histopathology detects that there is cancer, then second surgery may be required to remove all thyroid. However, if histopathology says that it is non cancer, then no further action is required and patient can remain disease free.

   In a minor proportion, a further special stain technique called as Immunohistochemistry is done over the histopathology sample. These all may be required to reach to a final and accurate diagnosis

The most common problems faced are either a high TSH or a low TSH.

TSH (Thyroid Stimulating Hormone) is a signal from the master gland in the brain that tells us that there is a change in the quantity of thyroid hormones circulating in the body.

Thyroid in Pregnancy

Pregnancy is a time where the smallest deviation from the norm evokes great fear and confusion in a mother ‘s mind.

Thyroid diseases are common in pregnancy because of many changes in the mother’s body to accommodate the newcomer.

The most common problems faced are either a high TSH or a low TSH.

TSH (Thyroid Stimulating Hormone) is a signal from the master gland in the brain that tells us that there is a change in the quantity of thyroid hormones circulating in the body.

High TSH signifies lower thyroid hormone concentration than required and requires replenishment of the hormone to normalise the TSH, so high TSH means- give me more.

Low TSH is a little more tricky, it means there is a little more thyroid hormone circulating in the mother’s blood.

But this does not mean it is necessarily harmful. Gestational thyrotoxciosis or pregnancy associated thyroid hormone excess is the usual cause and does not require any treatment.

Treatment is required in a few cases only. It is strongly recommended to consult an ENDOCRINOLOGIST nearest to you to decide whether treatment is required. In lots of cases, incorrect treatment is administered when not required.

The best treatment is prevention. So any lady planning pregnancy must test her thyroid functions (T3, T4, TSH) before conception to avoid undue stress and worry after conception in order to achieve and maintain a normal TSH prior to conception.

This webpage is edited by Dr. Tejal Lathia.

Dr Tejal Lathia is an Expert Endocrinologist, currently working as Consultant Endocrinologist at Fortis-Hiranandani Hospital and MGM New Bombay Hospital, Vashi, Navi Mumbai (Maharashtra) India.