Thyroid Disease 101

Written by: SphynxCatVP
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Due to the complex and varied nature of thyroid disease, this article makes the assumption that the reader is seeking general information appropriate to either young adults or adults rather than young children or infants. The links at the end of the article lead to more complete, detailed information if what you are seeking is beyond the scope of this article. There are many, MANY causes and treatments, for example, that are not covered in this basic overview.

What is thyroid disease?

Thyroid disease begins when the thyroid gland (part of the body's endocrine system) either produces too much ("hyperthyroid") thyroid hormones or not enough ("hypothyroid") thyroid hormomes. There are many reasons that either condition may develop, and it may affect people of all ages. While women are more commonly affected than men, thyroid disease CAN and DOES affect men as well. Unfortunately, if you have a more rare form of thyroid disease, you may find it difficult to convince a doctor to run a complete and thorough set of labs to get it properly diagnosed. For some, proper diagnosis has taken decades, and many changes of doctors.

Endocrine disorders in general are extremely complex, so a problem in one area can affect MANY other, seemingly unrelated, areas of the body. If you believe you have an endocrine disorder such as thyroid disease, enlisting the help of an endocrinologist for at least an evaluation appointment is essential - many other endocrine problems can mimic or cause secondary hypo/hyper thyroidism, so all other possible causes for the thyroid levels being "off" should be explored. Pituitary or hypothalmus issues, can lead directly to one or more seemingly thyroid-related problems - getting treatment for the wrong problem (unnecessary surgery, radation, etc.) will only make it worse in the long run.

Do remember that a lot of doctors tend to "see" a diagnosis that is in their speciality - an oncologist sees cancer, a cardiologist sees heart problems, and so on. If at all possible, you should ALWAYS get at least a second opinion (if not a third, fourth, fifth and sixth...) both from an endocrinologist who specializes in thyroid disease and/or Type 1 Diabetes, AND an endocrinologist who specializes in other endocrine disorders (and who may be more likely to catch non-thyroid causes of thyroid-seeming problems such as issues with the pituitary and hypothalmus glands.)

Normal thyroid hormone production chain

  1. Hypothalmus monitors the circulating levels of thyroid hormones (T4 and T3).
  2. If levels of either one are low, hypothalmus responds with TRH - Thyrotropin Releasing Hormone
  3. TRH stimulates the pituitary to produce TSH - Thyroid Stimulating Hormone
  4. TSH stimulates the thyroid gland to produce actual thyroid hormone (T4) until levels return to normal.
  5. T4 is broken down into T3 and other derivatives for use by various organs and muscles in the body.
  6. The presence of enough thyroid hormones (T4, T3) tells the hypothalmus to stop producing TRH.

Problems can develop anywhere in this chain of production, and for a variety of reasons. This is sometimes referred to as the "hypothalmus-pituitary-thyroid axis" because of how inter-related the three glands are.

What are the symptoms of thyroid disease?


Common symptoms demonstrate a slow or sluggish metabolism, and may include a combination of any or all of the following:

  • Anxiety
  • Coarseness of voice and impaired hearing
  • Cold intolerance, decreased sweating
  • Constipation
  • Dry, coarse skin
  • Fatigue
  • Hair loss (may happen repeatedly with fluctuations of hormone levels)
  • Heart: Decreased pulse, heart enlargement, decreased output
  • Headache
  • Impaired memory and cognition, poor concentration
  • Increased total cholesterol and LDL
  • Infertility
  • Muscle cramps and pain
  • Nerve-based pain
  • Possible insulin resistance
  • Side effects increase (either many, or severity) from medications due to slow digestion
  • Slow digestion
  • Sweating - Less - or complete lack of - sweating, while still getting overheated
  • Swelling of the face and extremities
  • Weight gain (with reduced appetite)
  • Weakness, fatigue, lethargy, and somnolence
  • Women: Menstrual irregularities
  • Note: Hair growth may completely STOP with really severe cases of hypothyroid.


Common symptoms demonstrate an overworked or over-stressed metabolism and may include a combination of any or all of the following:

  • Confusion/memory lapses/diminished attention span
  • Fear and depression
  • Hair loss (may happen repeatedly with fluctuations of hormone levels)
  • Heart: Rapid heart rate, palpitations
  • Heat intolerance
  • Increased sweating
  • Itchy skin
  • Muscle weakness
  • Nervousness and tremor, frequent emotional changes
  • Restlessness
  • Seizures
  • Weight loss (with increased appetite)

How is it diagnosed?

Conventional methods

Many doctors will test either a T4 and/or a TSH by themselves, since they've been taught that any other thyroid test is irrelevant. While this will catch most of the common thyroid problems, it will miss some of the more subtle or uncommon ones until the patient is in very ill health. I've seen anecdotes from people who've gone over a decade before getting a proper diagnosis because of this problem.

More complete method

A more complete thyroid panel should have all of the following items, and be tested on the same day:

  • TRH
    • Thyrotropin Releasing Hormone (Is the body calling for it?)
  • TSH
    • Thyroid Stimulating Hormone (Generated by the pituitary and it tells the body to make more thyroid hormone.) This is generally high in cases of hypothyroid (because the body needs to make more), and low in cases of hyperthyroid (because the body needs to make less.) This has a slower adjustment period (a few weeks to go up or down by significant amounts.) About the only time it won't rise is if the Free T4 is extremely high, the Reverse T3 is extremely high, or there's a problem with the hypothalmus or pituitary glands.
  • Free T4
    • Thyroxine (Amount available for conversion to T3)
  • Free T3
    • Triiodothyronine (Amount available for conversion to T2)
  • Reverse T3
    • Inactive/unusable form, sometimes high in times of stress. This is generated by the pituitary gland. Too much RT3 means the patient will have hypothyroid signs, despite a normal T3/T4 test. RT3 should be tested WITH the T3 - you need to see the ratio of one to the other.
  • Anti-Thyroid hormones
    • Thyroglobulin Antibodies (Tg Ab), Thyroid Peroxidase Antibodies (TPO AB) and Thyrotropin Receptor Antibody (TR AB) - these are typically seen in an autoimmune thyroiditis situation such as Hashimoto's Thyroiditis.

If testing is only being done on the T4/T3, you'll get a more accurate picture with several tests over the span of several days, because they can fluctuate rapidly.

A full thyroid panel is best with other supporting labwork, including a CBC w/ differential, Comprehensive Metabolic Panel, Cortisol, and other things. (See the RealThyroidHelp forum link at the bottom for details.) This will enable the doctor to better determine what the actual problem is - especially if the patient has a non-typical thyroid issue, and where in the thyroid production chain the problem lies - or if it's an adrenal, hypothalmus or pituitary issue instead of a true thyroid problem.

Treating the wrong problem, or not treating it at all because the doctor didn't run enough tests to even SEE the problem - only makes the condition worse over time.

How can thyroid disease be misdiagnosed?

Doctors may look at the symptoms, run a T4 or TSH and see no problem, and assume the thyroid is just fine. Meanwhile, the patient may get handed any of these other diagnoses - or ones not on this list - based on symptoms alone:

  • Accused of being just "fat and lazy" due to weight gain
  • Accused of being "noncompliant" with medications due to fluctuating thyroid levels
  • Anxiety disorders
  • Arthritis, various types
  • Autoimmune diseases of various types (if patient just keeps getting worse)
  • Chronic Fatigue Syndrome
  • Depressive disorders
  • Fibromyalgia
  • Heart disease / arrhythmia
  • Hypertension
  • Migraines
  • Neuropathy (due to pain)
  • Pre-diabetic condition (insulin resistance caused by thyroid issues)

How is it treated?

Treatment options depend on the cause, how fast the disease symptoms are progressing, and and whether they are permanent or a temporary side effect (postpartum being an example of a temporary situation.) If the problem is due to stress, generally getting rid of all or most of the stress will bring things back to normal, if it hasn't gone on long enough to create generalized adrenal fatigue.

Some medications can have a negative effect on the endocrine system in general, which can lead to symptoms of thyroid disease or other endocrine based problems. Sometimes stopping the medications causing the problem will help - sometimes it won't. It depends on how much damage was done by the medication and whether the body can recover on it's own.

Most cases of hyperthyroid (such as Grave's Disease) are treated with medications, radioactive iodine treatments (also known as "RAI") or surgical removal of all or part of the thyroid gland - the RAI and surgery effects are almost always permanent, leaving the person permanently hypothyroid (and requiring hypothyroid medications for the rest of their lives.)

Radioactive iodine is used because iodine is concentrated in high amounts in the thyroid gland, and in substantially smaller amounts throughout the rest of the body. There are two forms of radioactive iodine used - the form typically used for "uptake imaging" (nuclear scintigraphy; used to diagnose some types of hyperthyroid problems by the absorption pattern of RAI in the thyroid gland) is the milder I-123 isotope; this does not require any special precautions because it has a half-life measured in hours. The other form is the I-131 isotope, this is used in some tests, as well as in RAI treatment of some thyroid problems. Depending on the degree of treatment, special isolation procedures must be in place for the patient having I-131 treatment for up to a few weeks treatment is completed.

RAI treatment commonly has temporary side effects commonly including a sore throat lasting anywhere from a few days to a few weeks, difficulty swallowing, and fatigue.

For cases of hypothyroid, replacement hormones are the usual treatment of choice. There are natural and synthetic options available, but be aware that many doctors prescribe the synthetic form - this don't always work for the patient. The reason is that while natural thyroid hormone replacements ("Armour" is one brand cited often in thyroid forums) have T4 and T3 in relatively balanced amounts, the synthetic forms DO NOT. The synthetics are T4 OR T3, not both - and while most doctors are willing to prescribe the T4 synthetic, it may take some hard convincing - or the patient being nearly on death's door - for them to realize that T3 may be needed as well.

What other types of thyroid problems are there?


A goiter is a dramatic enlargement of the thyroid due to multiple benign growths within the thyroid. Generally this only causes problems when it interferes with breathing/eating/drinking, however they do need to be checked out to be certain it's not a cancerous growth. For cosmetic reasons, surgery may be performed to remove the growths even if it's not causing problems.

In many areas of the world, goiters are caused by an iodine deficiency. In America, due to the availability of iodized salt, this isn't as common (thought it can still happen on a salt-restricted diet, or if the patient uses a salt form that does not contain iodine. Careful use of iodine supplementation can avoid the deficiency problem.) In America, the more common reason is due to an increase in the TSH by the pituitary in response to a defect in thyroid hormone production within the thyroid gland itself.

Many goiters are a temporary situation, and will fade away with time even without treatment. Doctors who diagnose a goiter will likely take a wait-and-see approach, and monitor what happens over time.

Thyroid cancers (malignancies; typically treatable)

Most thyroid cancers are considered curable (because they're not as likely to spread to other areas of the body.) In the past, surgery has been done first, with RAI after if the surgery was unsuccessful. These days more patients are opting for RAI first because it's less invasive, then following up with surgery and/or more RAI afterward if it's necessary.

Some thyroid cancers may be subtle and hard to find, leaving the patient essentially "euthyroid" - little or no change in thyroid test values - and may be easy to miss AS a cancer for longer periods of time.

Solitary thyroid nodules

These are benign lumps that commonly arise within an otherwise normal thyroid gland. Typically there is only one lump (multiple lumps are usually referred to as "Goiter" instead). This is simply a harmless overgrowth of normal thyroid tissue, or it may be due to too little thyroid hormone being produced. Like goiters, these generally only require treatment if it interferes with breathing/eating/drinking,, and sometimes they also may be removed for cosmetic reasons.

Hyperthyroidism/Thyrotoxicosis (too much thyroid hormones)

This category includes a variety of diseases caused by too much creation and release of thyroid hormone. Graves Disease (a/k/a "diffuse toxic goiter") is the most common example, followed by Plummer's Disease (a/k/a "toxic multinodular goiter") and toxic adenoma to make the bulk of hyperthyroid cases, with other ailments being more rare. Generally these common ones are diagnosed with nuclear scintigraphy, which shows how much radioactive iodine ("RAI") is taken up by the thyroid gland - different hyperthyroid conditions affect how the RAI is absorbed, in specific patterns that indicate which type of hyperthyroid problem is affecting the patient.

A rare complication of hyperthyroid disease itself is a condition called "thyroid storm" - fatal if untreated, this typically occurs in patients with untreated or partially treated hyperthyroid who go through a traumatic event such as surgery, accidental trauma, serious infection, etc. (The body is trying to compensate for the change in hormone levels, but the compensation goes into overdrive, leaving the patient in a metabolically overstressed state.) If this happens, treatment must begin sooner rather than later - so recognition is based primarily on clinical signs of the hyperthyroid condition by medical personnel rather than waiting for lab results to come back.

Hypothyroidism, general (too little thyroid hormones)

In many parts of the world, hypothyroid is due to iodine deficiency, causing goiters. Usually hypothyroidism is a direct result of the thyroid gland not producing enough thyroid hormones, but sometimes it's a secondary effect of another problem such as a damaged pituitary gland, effects of certain medications (dopamine, lithium, thalidomide, etc.), prior radiation treatment for non-thyroid issues, tumors, and so on. Occasionally hypothyroidism can be caused by what's often described as a "conversion problem" - the body doesn't convert T4 to T3 in a timely manner. This does NOT show up on a T4 test - the problem is not with the production of T4 - but it will usually show up on a TSH test since TSH rises in response to a lack of either T4 or T3.

If a patient decides to go on a no-salt or salt-restricted diet, iodine should be supplemented (with selenium and a few other thyroid-supporting nutrients) so that the patient doesn't become hypothyroid out of a simple deficiency problem. If iodized salt is not desired (I don't like the flavor myself, so it wouldn't surprise me) then either try sea salt with trace minerals (there are some forms without iodine; avoid those for this purpose), or add kelp to the diet to provide the missing iodine. (Note: Kosher salt does NOT contain iodine!)

Thyroiditis (inflammatory/autoimmune process)

Thyroiditis is an inflammation of the thyroid gland. It generally has three phases: Acute (hyperthyroid state), subclinical, and inactive (closer to a hypothyroid state). The autoimmune disease known as Hashimoto's thyroiditis is probably the most well known example because it usually needs aggressive medical treatment by the time it's diagnosed, but it's actually not the most common.

Quite often similar effects happen within a few weeks of a viral infection (Mumps has been cultured in the past, but measles, influenza, mononucleosis, coxsackievirus and others have been seen in association with thyroiditis as well.) Thyroiditis may occur after pregnancy ("postpartum"), and is usually temporary (a few months) in duration. Common symptoms include pain in the neck (yes, literally!), fatigue, muscle pain and fever, in addition to anything else that happens to be going on. The thyroid gland is only mildly to moderately enlarged, sometimes 2-3 times normal, and often firm to hard in density.

How can medications affect thyroid levels?

Many medications can affect a patient's thyroid hormone levels, especially important when the patient is on thyroid hormone treatments. The most obvious cause of fluctuation is the timing of medication dosage versus the timing of the lab tests, or simply a change in the amount of the dose.

Other things that can affect this are:

  1. Medication potency fluctuations - between batches, and brands.
  2. Lab changes or errors (different lab used to run the tests, etc.)
  3. Timing of your dosage in the day - try taking it at the same time each day, rather than different times.
  4. Starting/stopping high fiber diet - fiber content should be relatively CONSISTENT, not variable.
  5. Calcium and iron interfere with the absorption of thyroid hormone replacements - separate doses by 2-4 hours.
  6. Soy products (high in isoflavones) may aggravate a thyroid condition, leading to a higher TSH.
  7. Eating too many goitrogenic (antithyroid activity) foods such as brussel sprouts, rutabaga, turnips, and others.
  8. Change of seasons - TSH can rise during colder months, and drop during warmer months. May be more pronounced in older people and in cold climates. Suspicion: Seasonal changes may be related to Vitamin D deficiency
  9. Estrogen replacement therapy - may need more thyroid hormone.
  10. Menopause - with fluctuating hormone levels - can impact TSH levels.
  11. Supplements / drugs containing iodine.
  12. Antidepressants (and similar) may impair the effectiveness of thyroid hormone replacement, and make TSH rise.
  13. Cholesterol medications may block thyroid hormones. If you must take these, separate from thyroid medications by 4-5 hours.
  14. Steroids - cortisone, etc. - can suppress TSH and block T4 > T3 conversion in some people.
  15. Stress and illness - the endocrine system responds to both, so periods of intense stress, or the relief of such stress, may impact TSH levels.
  16. Progression of thyroid disease - some types of thyroid disease get worse over time and higher doses of medication - or more aggressive measures such as surgery or RAI - may be needed.
  17. Pregnancy or "postpartum depression"

What makes food goitrogenic?

Goitrogens are naturally-occurring substances that can interfere with function of the thyroid gland. Foods containing goitrogens either block iodine utilization or interefere with the natural production, communication and conversion chain of thyroid hormones. These foods are best in small doses to minimize the impact on existing thyroid problems. These are compounds known as Isoflavones (in soy products) and Isothiocyanates (in cruciforous vegetables such as broccoli, cauliflower, brussels sprouts, cabbage, and more.) Cooking may inactivate these goitrogen substances, since they appear to be heat sensitive.

Soy products are a common example, but there are other goitrogenic foods as well. Fermented products (such as soy sauce) are ok, but non-fermented products still have the goitrogenic components. See the Bad Foods list at ThyroPhoenix and the goitrogen list at Stop the Thyroid Madness for more details. Soy products are especially hard to root out of the diet because they are hidden in many things, such as "textured vegetable protein", tofu, soy concentrate, soy protein drinks, and many other things.

In the absence of thyroid problems, these foods will not present problems, and should still be enjoyed for their nutritional value.

In closing...

I will repeat that there are many, many, MANY factors that can affect the extent and progression of thyroid disease. A large number of thyroid patients have united in forums and mailing lists in order to share their experiences and "what works for them" with others. Anecdotes from thyroid tests, symptoms, and whether natural or artificial thyroid hormone supplements work seem to be more accurate than what the doctors learn from pharmaceutical companies. Many patients with thyroid problems have had to "doctor themselves" in terms of research and understanding, in order to make their lives easier.

Please DO take the time to read the links below to get a better understanding of both anecdotal and conventional medical information. This is far too complex a topic to base your medical care decisions on just one article alone!