Hashimoto's disease, also known as Hashimoto's thyroiditis, is an autoimmune disease that affects the functioning of your thyroid.
Because it shares many symptoms with other thyroid conditions, Hashimoto's disease can be difficult to detect early. Once the disease is suspected, doctors often rely on blood tests to confirm their diagnosis.
Can you have Hashimoto's disease with normal thyroid levels? In this article, we'll answer that question and explain in greater detail what Hashimoto's disease is and how to know whether you have it.
Hashimoto's disease is an autoimmune disorder. Autoimmune disorders occur when your body's immune system mistakes parts of your body for a threat to your health and attacks them.
Autoimmune disorder can impact almost every part of the body. In the case of Hashimoto's disease, the thyroid becomes the target of the immune system's attack. As your immune system attacks your thyroid, its function begins to decline.
In the early stages of the disease, the results on thyroid output can be unpredictable, but as the condition of the thyroid worsens, it will be unable to produce enough thyroid hormones to meet the body's needs. This is a condition known as underactive thyroid or hypothyroidism.
It's important to note the distinction between Hashimoto's disease and hypothyroidism. While Hashimoto's disease can result in hypothyroidism once the thyroid becomes too damaged, it's not the only cause of hypothyroidism.
An underactive thyroid can have different causes,¹ so low thyroid output alone isn't enough to diagnose Hashimoto's disease.
Hashimoto's disease itself doesn't have any symptoms that are unique to it. Instead, the condition is detected by its effect on the thyroid.
We've talked about how Hashimoto's disease degrades the function of the thyroid and reduces its output, so the symptoms of hypothyroidism could be a reason to evaluate your chances of having Hashimoto's.
However, in the early phases of the disease, the attacks on your thyroid have not yet degraded its performance. Instead, the gland can erratically behave as it finds itself under attack.
During these early phases, the gland may produce too much hormonal output. This means that symptoms of overactive thyroid or hyperthyroidism can also be an early sign of Hashimoto's.
If you suspect you have Hashimoto's disease, below is a list of the symptoms you should look out for:
Goiter is the medical term for enlargement of the thyroid. Goiters are usually the result of a thyroid that isn't functioning properly. Hashimoto's disease is one of the many conditions that may prevent your thyroid from working correctly. If you have an enlarged thyroid, your doctor will be able to help you find the reasons.
Goiters aren't always easily visible, but there's a home check you can perform to see if there's any unusual growth on your thyroid. We'll discuss this test in greater detail later.
Hyperthyroidism is when your thyroid gland produces more thyroid hormones than your body needs. As your thyroid comes under attack from your immune system due to Hashimoto's disease, it can become overactive.
The symptoms of an overactive thyroid then become potential symptoms of Hashimoto's disease. Common indications of hyperthyroidism include:
Unexpected weight loss
Higher than usual appetite
Rapid or irregular heartbeat
Being unusually bothered by the heat or sweating more than usual
Weakness or shaky hands
More frequent bowel movements
Nervousness or irritability
Whether it's because of the initial attack on it, or the continued degradation of its function by Hashimoto's, the thyroid can also produce too little hormonal output for the body due to the disease. When this happens, Hashimoto's disease will cause the body to present symptoms of hypothyroidism.
Underactive thyroid presents itself differently from person to person, but a common set of symptoms of the condition include:
Unexpected weight gain
Slowed heart rate
Increased sensitivity to cold weather
Pain in the joints or muscles
Irregular menstrual periods
In extreme cases, the thyroid produces so little output that it becomes dangerous.
Although rare, extreme cases of hypothyroidism can be life-threatening and cause a condition known as myxedema coma.
People who suffer from myxedema coma aren't usually unconscious, but they experience extreme lethargy and low body temperature that is considered a medical emergency.
Because the symptoms of Hashimoto's disease are the same as those of many other thyroid conditions, it can be difficult to know without medical advice whether the disease is the cause of the symptoms.
If you're experiencing any of the symptoms of poor thyroid function, a doctor can narrow things down for you.
However, there are some things you can do at home that may help point the doctor in one direction or another.
If your doctor suspects Hashimoto's to be the reason for your thyroid problems, they will likely ask you some questions to determine how at-risk you are for the disease.
Hashimoto's disease can be hereditary, so if you have a family history of it, the chances of it causing your thyroid problems are higher. Several genes² have been shown to increase a person's susceptibility to the disease.
Being a woman
Women are significantly³ more likely than men to develop Hashimoto's disease. This is especially true between the ages of 40 and 60.
Consuming excessive iodine
Consumption of iodine is known to increase the chances of developing the condition. If you think you may have developed Hashimoto's disease, check your diet for food high in iodine.
Your doctor will perform a physical exam to see if your thyroid is enlarged. You can screen for this at home using a simple procedure that only requires a handheld mirror and a glass of water.
Here’s how to do the neck check at home:
Hold the mirror with one hand to give yourself a clear view of the area between your collarbone and your voicebox. The thyroid is located between those two locations.
While keeping the mirror pointed where you need it to be, tilt your head back.
Take a drink of water and swallow it, paying attention to your neck in the mirror as you do.
While swallowing, look for any bulges or protrusions in the thyroid area. The thyroid is below Adam's apple, closer to the collar bone.
Contact your doctor if you see any bulges or protrusions in the mirror.
When you go to the doctor with suspicion of Hashimoto's disease, they will start by performing some of the tests we've already discussed.
They'll ask you about your risk factors for Hashimoto's and other possible causes of your thyroid problems. They'll then perform a physical exam to check for the presence of a goiter on your neck.
If your doctor suspects you to have Hashimoto's disease, they’ll order a blood test to help confirm the diagnosis. Your doctor will be most interested in checking your thyroid-related levels and antibodies, including:
There are two major hormones produced by the thyroid — T3 and T4. When these hormones are too high or too low, you begin to see the symptoms we discussed earlier. Your doctor will look at these levels to see if you have hyperthyroidism or hypothyroidism.
As Hashimoto's progresses without treatment, hypothyroidism will likely set in, and your thyroid hormone levels will be low.
Thyroid-stimulating hormone (TSH)
Having thyroid hormone levels come back to normal doesn't necessarily mean there isn't a problem. The human body is very good at adapting itself when issues occur.
If the immune system attacks the thyroid by Hashimoto's disease or simply isn't producing enough thyroid hormones, the body will compensate by asking the thyroid to make more or less of them to restore normal levels.
Your body controls the amount of hormones produced by the thyroid using another hormone produced by the pituitary gland called TSH.
If the thyroid hormone levels are normal, but TSH is elevated, it could signify that the body is compensating for a poorly functioning thyroid.
Thyroid peroxidase (TPO) antibodies
It's possible to have Hashimoto's disease but not yet have a severe enough case that your thyroid function has been impacted. In these cases, you can have Hashimoto's disease with normal TSH.
If your TSH levels aren't normal, there are also possible other causes.
Testing for TPO antibodies can help your doctor confirm a Hashimoto's disease diagnosis. These antibodies attack the TPO enzymes in your thyroid. When you have Hashimoto's thyroiditis, your TPO antibodies will be elevated. This is because the disease causes your immune system to produce more of them in its attack on your thyroid.
In cases where Hashimoto's disease is present but has not yet affected your thyroid hormone output, your doctor will likely choose to simply monitor the situation rather than put you on a treatment plan.
If your thyroid levels have been affected, however, the condition is treatable through several methods, including:
The primary treatment for Hashimoto's disease involves putting you on hormone replacement therapy to substitute for the lack of hormones produced by the thyroid gland.
Levothyroxine is a medicine that's identical to the thyroxine produced naturally by your thyroid. It comes in a simple pill form that you'll regularly take as prescribed by the doctor. The medicine also comes in a liquid or soft-gel form for those who have trouble taking pills.
Regular blood tests
After a diagnosis of Hashimoto's disease, you'll need to go in for regular blood tests to check the level of your thyroid hormones.
These tests serve two purposes. When you are first prescribed hormone replacement therapy, your doctor must get the dosage right. During this time, more frequent blood tests will be taken to adjust the dosage of the medicine properly.
Once the dosage is correct, the blood tests will become less frequent and will ensure that conditions haven't changed to the point that a modification of the dosage has become necessary.
Some changes to your diet may be necessary when you have Hashimoto's disease. Certain foods, such as grapefruit, soy, espresso, and multivitamins, can make it harder for your body to process levothyroxine.
Because of the connection between iodine and Hashimoto's disease, your doctor is also likely to recommend that you stay away from foods high in iodine.
Clinical trials are a form of medical research that relies on volunteers, and it helps find new ways to screen for, diagnose, and treat medical conditions, including Hashimoto’s disease.
With Hashimoto's disease, antibodies attack the enzymes in your thyroid and weaken it, causing it to produce fewer of its hormones. By monitoring for signs of abnormal thyroid function, you can detect thyroid-related conditions such as Hashimoto's disease early and minimize their effects on your body.
Hypothyroidism (Underactive thyroid) | (NIDDK) National Institute of Diabetes and Digestive and Kidney Diseases
Hashimoto's syndrome | (GARD) Genetic and Rare Diseases Information Center
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