Hashimoto’s Thyroiditis And How It's Diagnosed

Hashimoto's thyroiditis is a condition that goes by many names. You may also see it referred to as:

• Hashimoto's disease

• Hashimoto's syndrome

• Chronic thyroiditis

The disease is an autoimmune illness that targets the thyroid gland, an important hormone producer for normal bodily function.

As the first step to getting a diagnosis is understanding when you may have it and telling a doctor about any concerns, we'll first go over the risk factors and symptoms of the disease. We'll then look at the tests your doctor will likely perform to confirm that you have the condition.

What is Hashimoto's thyroiditis?

Hashimoto's thyroiditis is an autoimmune disease. This means that your immune system, which normally fights off illness, begins to attack your body. Autoimmune diseases can affect nearly any part of the body.

As the name implies, Hashimoto's thyroiditis is an autoimmune condition that causes your body's immune system to attack your thyroid.

Potential complications

The end result of your immune system attacking your thyroid is that the gland no longer produces as much of its vital hormones as a healthy gland would. This is a condition known as ‘hypothyroidism’ and is a common result of Hashimoto's thyroiditis.

Aside from a number of symptoms which we'll discuss later, the big risk of complications from hypothyroidism is myxedema coma, which results when hypothyroidism gets so bad, the body's functions slow down to life-threatening levels.¹

Risk factors

It isn't known exactly what causes Hashimoto's disease, but we do have some reliable data on the type of people who are most likely to develop the condition.

Familiarizing yourself with the risk factors will help you gauge the likelihood that you may have the condition should you develop some of the symptoms.² This is particularly useful, as none of the symptoms are unique to this particular illness.

Having a genetic predisposition to the disease

There are a number of genetic factors that can increase the chances of a person developing Hashimoto's disease. The easiest to track is heredity. If someone in your family has had the disease, you are at an increased risk of getting it.

There are less obvious genetic predispositions. Several genes have been shown to increase one's susceptibility to Hashimoto's thyroiditis, including human leukocyte antigen (HLA), protein tyrosine phosphatase nonreceptor-type 22 (PTPN22), and more.²

Being a female

Women are more likely than men to develop Hashimoto's thyroiditis, especially during middle age. This is believed to be at least partly due to the fact that women have two X chromosomes, and the X chromosome contains several genes that are important for proper immune function.²

The additional X chromosome in women increases the chance for genetic abnormalities that might lead to Hashimoto's. At least one study has also shown a link between estrogen levels and proper thyroid function.³

Excessive iodine levels

Individuals with excessive iodine intake are more likely to experience Hashimoto's syndrome. Iodine intake appears to have a strong connection to thyroid function, so this works the other way as well.

One study showed that subjects with iodine deficiency were less likely than those with sufficient iodine intake to develop the condition.²

Exposure to radiation

Another environmental factor that increases the risk of Hashimoto's disease is exposure to radiation.⁴ This risk can come from catastrophic events such as nuclear fallout, but also more mundane sources of radiation, such as that used in medical devices.

Having other autoimmune diseases

Having another autoimmune disease can increase the risk of Hashimoto's, and vice versa. The most common autoimmune disease that exists alongside Hashimoto's is rheumatoid arthritis.⁵

Bacterial or viral infections

Certain other medical conditions are known to increase the chances of a person developing Hashimoto's thyroiditis. These include viral infections such as hepatitis C,² and certain bacterial infections such as helicobacter pylori.⁶

Symptoms

Hashimoto's syndrome doesn't have any symptoms that are unique to it. Instead, it makes itself known through its effect on the thyroid.

As mentioned above, the end result of the immune system's attack on the thyroid is to decrease its output and cause hypothyroidism.

However, in the early stages of the disease, it could have the opposite effect and cause an increase in thyroid activity (hyperthyroidism).

Therefore, symptoms of both extremes could indicate the presence of Hashimoto's, especially if you fall under one of the risk factors mentioned earlier.

Symptoms of hyperthyroidism (overactive thyroid)

Hyperthyroidism presents differently from person to person.  Some common symptoms are listed below, though an individual likely won't experience all of them.⁷

Older patients may also experience symptoms that younger ones don't, such as lack of appetite.

• Increased appetite

• Unexplained weight loss

• Intolerance to heat or unusual sweating

• An increase in heart rate or an irregular heartbeat

• Muscle weakness or shakiness

• Increased bowel movement frequency

• Irregular growth of the thyroid gland, known as a ‘goiter’

• Nervousness or irritability

• Trouble sleeping

• Fatigue

Symptoms of hypothyroidism (underactive thyroid)

Like hyperthyroidism, the symptoms of hypothyroidism vary from person to person.¹ In many cases, the symptoms caused by an underactive thyroid are the opposite of those caused by an overactive one.

• Unexplained weight gain

• Intolerance to cold

• Decreased heart rate

• Pain in the joints or muscles

• Irregular menstrual periods

• Fertility problems

• Dry skin

• Thinning hair

• Depression

• Fatigue

How Hashimoto's thyroiditis is diagnosed

If you have any of the symptoms and suspect that you may have Hashimoto's disease, you can perform an at-home thyroid neck check that may provide additional clues. However, a doctor will be able to provide you with a more definitive diagnosis using a few simple tests.

At-home thyroid neck check

Your doctor can perform a physical exam to see if your thyroid is enlarged, but you can do a self-check at home using a mirror and a glass of water. The thyroid neck check can be completed in five simple steps.

1. Extend the mirror out with one hand so that you have a clear view of the area between your collarbone and your voicebox. This is where the thyroid is located.

2. Tilt your head back, taking care that you can still see the mirror and it's still pointing at the correct location.

3. Take a drink of water and swallow.

4. Observe your neck as you swallow. You're looking for any bulges or protrusions in the area of the thyroid. The thyroid is below Adam's apple, closer to the collar bone.

5. Contact your doctor if you see any bulges or protrusions.

Tests a doctor may perform

Testing for Hashimoto's disease is a fairly simple process. Your doctor will begin by asking about your symptoms and risk factors to narrow down the cause of your problem.

If the doctor suspects Hashimoto's thyroiditis, here's what you can expect:

Physical exam

The doctor will likely begin by performing a physical examination of your thyroid to check for a goiter. This process will be similar to the at-home check described above.

Blood tests

A physical exam alone can't diagnose Hashimoto's syndrome, because the symptoms are similar to many other conditions. To further confirm the diagnosis, doctors rely on additional testing.⁸

A number of blood tests are useful in narrowing down the cause of thyroid trouble to autoimmune issues.

• Thyroid hormones T4 (thyroxine) and T3 (triiodothyronine): These are the hormones produced by the thyroid gland. If there are too few or too many, it's an indication that the thyroid isn't functioning properly.

• Thyroid-stimulating hormone (TSH): This hormone tells your thyroid to produce its hormones. If the thyroid isn't producing what it should, this value will be abnormal as the body tries to correct the imbalance.

• Thyroid peroxidase antibodies (TPO): Thyroid peroxidase is an enzyme in your thyroid. Thyroid peroxidase antibodies attack that enzyme. Elevated levels of these are usually, but not always, a sign of Hashimoto's thyroiditis.

Ultrasound

An ultrasound of the thyroid can also help with the diagnosis. Not only will the ultrasound give the doctor a better look at the size of your thyroid, but it will help rule out other possible causes should it be confirmed that the thyroid is enlarged.

The lowdown

The thyroid regulates many areas of the body that affect your day-to-day well-being, and although rare, myxedema coma is a serious condition that can result from hypothyroidism.

Contact your doctor if you notice any of the symptoms of abnormal thyroid function. This is the first step in finding out whether you may have Hashimoto's thyroiditis or one of the other conditions that can affect thyroid output.