January was Thyroid Disease Awareness month and thyroid disorders are very common.  Unfortunately, it’s usually not the answer to the 10 pounds you are trying to lose.

What is the Thyroid?

The thyroid is a gland located in the neck near the “Adam’s Apple”.  It’s job is to produce Thyroid Hormone (T4, T3) – which helps set your metabolism and plays a role in almost all of your bodies’ functions.
Your thyroid gland is regulated by another gland called the Pituitary Gland, located in the brain. The pituitary acts as a thermostat to control the thyroid – the technical term for this is a “negative feedback loop.”  The pituitary measures the amount of thyroid hormone in the body.  Based on this measurement, it secretes either more or less Thyroid Stimulating Hormone (TSH) telling the thyroid gland to increase or decrease thyroid hormone production.  So TSH goes up when the pituitary senses low levels of thyroid hormone and goes down for high levels.  That is why when your thyroid is tested, the doctor looks at both the level of thyroid hormone in you blood as well as the TSH level.  This allows assessment not only of how your thyroid gland is working, but also how hard it is working to maintain a level.
Based on the values of the TSH and T4 we can begin to tell if the problem is in the thyroid gland itself or in the pituitary gland regulating your levels.  Testing T3 levels can be helpful when the TSH/T4 levels are borderline or someone’s symptoms and the test results don’t make sense – but most people can be diagnosed and managed without it.

Thyroid Disorders

There can be structural issues of the thyroid – nodules, cysts and tumors (both cancerous and benign).  These may or may not affect the overall functioning of the thyroid, but may be felt on physical exam or found when evaluating other neck issues.  I can write more about those issues in a future post if people are interested.  The remainder of this article will focus on the two major functional thryoid disorders – hypothyroid (underactive) and hyperthyroid (overactive).  There can be many causes of of hypo- and hyper- thyroidism, which is part of the challenge – determining your diagnosis – specifically what is your thyroid issue?


This is the most common of the functional thyroid disorders.  Hypothyroidism means an underactive thyroid gland.  Symptoms include fatigue, constipation, dry skin and hair, weight gain, swelling, depression or change in concentration.  The symptoms can also be variable.  Many people are diagnosed with minor hypothyroidism (called subclinical) when their tests are abnormal during a routine exam.  There are many causes of hypothyroidism.
If the pituitary gland is not working properly and cannot produce TSH, then the thyroid gland, although normal, will not produce thyroid hormone.  This is usually due to an abnormal growth in the pituitary such as an adenoma (a benign tumor). This type of hypothyroidism occurs in about 1% of cases.
Autoimmune thyroiditis – also known as lymphocytic or Hashimoto’s Thyroiditis is the common cause of hypothyroidism.  The body’s immune system recognizes the thyroid gland as foreign and starts to attack it by making antibodies against it.  As the structure of the gland gets damaged, it is unable it produce thyroid hormone and you develop hypothyroidism.  Your blood tests will show a high TSH and a low T4.  There is also a blood test to detect the anti-thyroid antibodies, which, if present, confirm the diagnosis.
Other forms of hypothyroidism are more difficult to find a direct cause for, but they are all diagnosed by a high TSH and a low T4.


When the thyroid gland is overactive – making too much thyroid hormone – a person is Hyperthyroid.  The most common cause for hyperthyroidism is Grave’s Disease – another autoimmune disease of the thyroid gland.  In Grave’s Disease, the body makes antibodies against the thryoid gland like in Hashimoto’s Thryroiditis, but instead of destroying the gland, these antibodies stimulate the thyroid gland to continue producing thyroid hormone regardless of what the pituitary gland tells it to do.  These antibodies are called Thyroid Stimulating Immunoglobulins (TSI) and can be tested for in the blood.
The symptoms of hyperthyroidism are feeling keyed up (over caffinated), diarrhea, weight loss, rapid heart rate and hair loss.  Grave’s Disease can also cause the eyes to bulge due to antibodies building up in the muscles behind the eyes.


Hypothyroidism is treated mostly with levothyroxine, which is synthetic T4.  It is an exact match for what the body naturally produces, as opposed to earlier treatments which used animal thyroid glands.  There are many dosages available, allowing us to match the dosage given to what your body needs.  We measure success by following the TSH.  Based on your TSH level and how you feel, we can be sure to get the dosage specific to your needs.  There are a small percentage of patients who do not tolerate levothyroxine, and may use  different medications.


Hyperthyroidism is treated in a few ways.  Firstly, if a person’s heart rate is very rapid, medication to block the effect of excess thryoid hormone (called beta blockers) can be used to treat the symptoms while treatment to regulate the thyroid gland takes effect.  There are medications called methimazole and propylthiouracil (PTU) which can be used to reduce the production of thyroid hormone.  Radioactive iodine can be given to destroy a portion of the thyroid, reducing its ability to produce hormone.  The thyroid gland can be surgically removed as well.  Surgery and radioactive iodine have a high rate of making someone hypothyroid, which would then require lifelong levothyroxine.

How does this affect MY practice

Thyroid tests are something I order as part of general physical exam.  Because the symptoms can be subtle, we can diagnose and begin treating a problem before it gets too severe if we screen for thyroid disorders.  Thyroid tests are also ordered when someone complains of the symptoms of either hyper or hypothyroidism.  When the tests come back abnormal, I order the antibody test – if the cause of thyroid disease is autoimmune it is important to know – as people with one autoimmune disease are at higher risk of developing another.
If a person is hypothyroid, they are usually given levothyroxine, and a TSH level is repeated in about 6 weeks, then, based on those results the dosage is adjusted until symptoms are controlled and the TSH is in the proper range.
Many people ask me about over the counter thyroid supplements instead of prescription levothyroxine.  I generally advise against this for a few reasons:
  • They are not FDA regulated
  • The dosages can not be as finely tuned as levothyroxine can.  They are usually made up from animal thyroid glands and can contain impurities
  • A recent NY Times article quoted a study that showed 9 out of 10 thyroid supplements tested at random contained 2-3 times the starting dosage of thyroid hormone – which should only be dispensed with a prescription
When hyperthyroidism is diagnosed, we immediately focus on controlling the symptoms such as anxiety, heart palpitations and tremor.  Then a discussion as to the best means to control their thyroid gland’s production – medication, radioactive iodine or surgery.
Thyroid problems are very common and can have a large impact on  a person’s sense of well being.  By using a person’s own control systems to dose their medication, we can come very close to restoring their thyroid levels to what their body needs.  Together, doctor and patient can review symptoms, get tests and most importantly, get a diagnosis.  Then a treatment plan and healing begins.


The path to wellness begins with a proper diagnosis

Published by Eric Goldberg, MD, FACP

I am a Board Certified Internal Medicine physician. I currently practice at and am the Medical Director of NYU Langone Internal Medicine Associates. Posts are my opinion and not medical advice or an official position of NYU Langone Medical Center.

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