The thyroid gland is small, but mighty, as it affects almost every process and organ system in the body. As an endocrinologist, I help patients manage issues related to hormones in the body. That includes disorders of the thyroid. But before I talk about thyroid problems, I want to give you some facts.
Where is the thyroid gland located and what does it do?
The thyroid gland is a small gland located in the lower front part of the neck. It’s sort of shaped like a bowtie or butterfly, and is about four inches across. It only weighs 10-20 grams.
Even though it’s very small, the thyroid controls almost every function of the body, including:
- Heart rate
- Body temperature
- Weight and metabolism
- Growth (in children) – both physical and neuro development
- Skin texture and health
- Menstrual cycles in women
- Mood, depression, anxiety
- Mental clarity and concentration
- Bowel regularity and habits
- Muscle strength and coordination
- Bone health
As you can see, when something within the thyroid isn’t quite right, the rest of the body can be significantly affected.
What are the most common causes of thyroid problems?
Thyroid problems fall into three major categories with two relating to function:
- Hypothyroidism (underactive thyroid)
- Hyperthyroidism (overactive thyroid)
- Thyroid tumors
Each of these issues has a different symptom set, and different causes (genetic, acquired or unknown).
Hypothyroidism is the most common type of thyroid problem. It occurs when the thyroid is not producing enough thyroid hormone. Some of the causes of hypothyroidism include genetic predisposition (an example is Hashimoto’s Disease), which is an immune reaction that can destroy the thyroid. Other causes include thyroid inflammation, surgical removal of the thyroid (because of a tumor), radiation damage (if the neck area had been treated for cancer, for example, or a person had received radioactive iodine for treatment of overactive thyroid), or finally, being born without the thyroid.
Symptoms of hypothyroidism include:
- Weight gain, despite poor appetite—slowing of metabolism
- Dry skin, brittle hair
- Slow heart rate
- Heavy menstrual cycles
- Difficulty with concentration
- Poor tolerance of being cold
The simplest diagnosis is a blood test, checking for TSH (thyroid stimulating hormone) produced by the pituitary gland in the brain. This hormone stimulates the thyroid.
A hypothyroidism diagnosis usually comes with a medication that acts as a synthetic version of the thyroid hormone. It’s taken one time per day, first thing in the morning on an empty stomach (an hour before breakfast). Food items containing calcium, iron or fiber should be spaced away from the medication by about 4 hours.
Medication doses vary by hormone levels, age, weight, and other health factors.
Is hypothyroidism hereditary?
Yes, thyroid disease is very commonly hereditary. That’s why if someone has underactive thyroid, their children/siblings should be monitored, and then tested if they show any signs of hypothyroidism. Fortunately, when you know it runs in the family you can watch for it. With early detection, hypothyroidism is easily diagnosed and treated.
Other facts about hypothyroidism
- Hashimoto’s disease is an autoimmune disorder, and is the most common cause of hypothyroidism in the U.S. We usually screen for vitamin B12 deficiency in patients with Hashimoto’s. This deficiency can cause pernicious anemia (low red blood cells).
- Thyroid disease in general affects more women than men—a ratio of 9 to 1. Usually we see the onset of this at a time of hormone change, such as puberty, pregnancy, postpartum and menopause.
- Most women are screened for thyroid issues while pregnant, as thyroid issues can affect outcomes for the baby. If a woman is recommended to have thyroid replacement hormone during pregnancy, the dosage is often 30% above the maintenance dose to support the pregnancy.
- At menopause, usually the dosage can be reduced slightly as estrogen levels go down. Too much thyroid hormone could lead to complications such as heart disease/rhythm irregularities and osteoporosis, so it’s important to manage the dose.
- The most common replacement thyroid hormone is T-4 (brand name, Synthroid). Armour Thyroid is also an acceptable option and one some women prefer. With treatment and hormone replacement, the symptoms of hypothyroidism are significantly improved.
Hyperthyroidism is less common than hypothyroidism. It can also be caused by an immune system problem (such as Grave’s Disease), or it can be caused by thyroid nodules that produce too much thyroid hormone.
Symptoms of hyperthyroidism include:
- Weight loss, despite a large appetite
- Rapid heartbeat and even palpitations
- Frequent bowel movements
- Shakes, tremors
- Anxiety, feeling “wound up” and insomnia
- Muscle weakness, changes in walking gait
- Light or even absent menstrual cycles
- Brittle hair
- Excessive sweating, heat intolerance
- Blurred vision, and sometimes “bulging” eyes appearance.
The simplest test to diagnose hyperthyroidism is a blood test checking for TSH (thyroid stimulating hormone). Produced by the pituitary gland in the brain, this hormone stimulates the thyroid. In hyperthyroidism, TSH would be low, because the thyroid doesn’t need additional stimulation—it’s already over-active. We also check the T4 (thyroxine) level because it is the hormone actually produced by the thyroid.
Treatment for hyperthyroidism
- Medications that make the thyroid slow down and make less hormone. A common medication is Tapazole (methimazole), but it should not be used during the first trimester of pregnancy. PTU (propyl thiouracil) is an alternative for pregnant women.
- Radioactive iodine treatment, which is a pill that eliminates thyroid hormone production. Yes, most patients do end up having underactive thyroid after this, but as I mentioned earlier, this condition is more easily addressed and treated.
- Surgery to remove the thyroid. (Again, that will lead to underactive thyroid, but that is treatable.)
Thyroid tumors, or nodules, are very common. They can be found in about 1/3 of the population, and can be assessed by simple thyroid ultrasound. Many times, the initial discovery is made during a routine doctor’s exam. Sometimes when certain imaging tests of the neck are done (such as to look at a spinal problem), these tumors/nodules are found “by accident.”
Thyroid nodules vary in size, and generally don’t cause any problems. However, some nodules can be large and cause difficulty swallowing or even choking.
Evaluating thyroid tumors
If someone has a thyroid nodule, we want to assess three things:
- If the nodule is affecting thyroid function, causing hyperthyroidism.
- If it’s large enough to cause physical problems, such as trouble swallowing.
- Rule out possible cancer. This is usually done with a fine-needle biopsy.
If none of these are the case, we leave the nodules alone and monitor them with ultrasound. If there are problems, we address them individually, and then later, address any function issues that may arise.
While not large in actual size, the thyroid gland packs a big punch when it comes to your overall health. If you experience the symptoms listed above, make it a priority to talk to your primary care provider. He or she can provide the appropriate initial testing, and then a referral if needed.