Thyroiditis is the medical term for inflammation (swelling) of the thyroid gland, which can either cause abnormally high or low levels of thyroid hormones in the blood.
The thyroid gland is a butterfly-shaped gland found in the neck. It produces hormones that are released into the bloodstream to control the body's growth and metabolism.
They affect processes such as heart rate and body temperature, and help convert food into energy to keep the body going.
There are several different types of thyroiditis. The common types are:
- Hashimoto's thyroiditis (the most common)
- de Quervain's or subacute thyroiditis
- post-partum thyroiditis (triggered after giving birth)
- silent or painless thyroiditis
- drug-induced thyroiditis
- radiation-induced thyroiditis
- acute or infectious thyroiditis
The symptoms and treatment of these conditions are briefly described below.
Hashimoto's thyroiditis is an autoimmune condition. This means your immune system mistakenly attacks your thyroid gland, causing it to gradually swell and become damaged.
As the thyroid gland is slowly destroyed over time, it is unable to produce sufficient amounts of thyroid hormone. The medical term for low levels of thyroid hormone in the blood is hypothyroidism.
This leads to symptoms of an underactive thyroid gland, which are very general and can include:
The swollen thyroid gland may also cause a lump to form in your throat, known as a goitre.
It may take months or even years for the condition to be detected, because the disease progresses very slowly.
The cause of Hashimoto's thyroiditis is not understood, but it sometimes appears to run in families, suggesting your genes may make you more likely to develop the condition.
Hashimoto's thyroiditis cannot be cured, so the low levels of thyroid hormone are usually permanent. However, the symptoms are often easily treated with the thyroid hormone replacement medication levothyroxine, which is usually taken for life.
Surgery is only rarely needed, for instance if your goitre is particularly uncomfortable or there are suspicions of cancer.
De Quervain's (subacute) thyroiditis
It's most commonly seen in females aged 20 to 50.
De Quervain's thyroiditis usually causes a fever and pain in the neck, jaw or ear. It can also cause your thyroid gland to release too much thyroid hormone into the blood (thyrotoxicosis), leading to symptoms of an overactive thyroid gland (hyperthyroidism), including:
The palpitations and shakes associated with thyrotoxicosis can be treated with a beta-blocker.
The pain caused by de Quervain's thyroiditis can often be relieved with painkillers such as aspirin, or non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen. In the cases where these medications are ineffective, corticosteroid medication may be prescribed.
De Quervain's thyroiditis settles down after a few days and is often followed by a spell of hypothyroidism lasting a few weeks or months, before the thyroid gland recovers completely.
Very occasionally, the condition may recur or the low levels of thyroid hormones caused by it can be permanent and may require long-term treatment with thyroid hormone replacement medication.
Like Hashimoto's thyroiditis, post-partum thyroiditis is an autoimmune condition, but it only happens in women who have recently given birth.
In post-partum thyroiditis, your immune system attacks your thyroid gland within around six months of giving birth, causing a temporary rise in thyroid hormone levels (thyrotoxicosis) and symptoms of an overactive thyroid gland.
Then, after a few weeks, your thyroid gland becomes depleted of thyroid hormone, leading to low levels of thyroid hormone and symptoms of an underactive thyroid gland.
However, not every woman with post-partum thyroiditis will go through both these phases.
If low thyroid hormone levels are causing severe symptoms, you may need to take thyroid hormone replacement until the condition gets better.
In most women with the condition, thyroid function returns to normal within 12 months after the baby is born, although the low thyroid hormone levels can sometimes be permanent.
Silent (painless) thyroiditis
Silent thyroiditis is very similar to post-partum thyroiditis. It is also an autoimmune condition, but is not related to giving birth and can occur in both men and women.
Like postpartum thyroiditis, there may be a phase of high thyroid hormone levels (thyrotoxicosis), causing symptoms of an overactive thyroid gland. This may then be followed by a phase of symptoms of an underactive thyroid gland, before the symptoms eventually go away within around 12 to 18 months.
If low thyroid hormone levels are causing severe symptoms, you may need to take thyroid hormone replacement until the condition gets better. In a few cases, the low thyroid levels can be permanent.
Thyroiditis can also be triggered by medications including interferon, amiodarone, lithium and a class of drugs to treat certain cancers (which include sunitinib), if these medicines damage the thyroid gland.
There may be symptoms of an overactive thyroid gland or symptoms of an underactive thyroid gland, but these are usually short-lived and may get better after you stop taking the medication causing the condition. However, you should not stop taking any medication that has been prescribed for you without first discussing it with your doctor.
Drug-induced thyroiditis can sometimes cause pain in the area around the thyroid gland. This can often be relieved with NSAIDs, although corticosteroid medication may occasionally be needed.
Radioactive iodine treatment for an overactive thyroid gland or radiotherapy for certain cancers can also damage the thyroid gland, leading to symptoms of an overactive thyroid gland or symptoms of an underactive thyroid gland.
The low levels of thyroid hormone after radioactive iodine is usually permanent, and may cause symptoms of an underactive thyroid gland that will need to be managed with lifelong thyroid hormone replacement treatment.
Acute or infectious thyroiditis
Acute or infectious thyroiditis is usually triggered by a bacterial infection. It is rare and is associated with either a weakened immune system or, in children, with a problem in the development of the thyroid.
These symptoms will usually get better when the infection is treated with antibiotics. In the meantime, thyroid pain can often be managed with NSAIDs. Children will usually require an operation to remove the abnormal part of the thyroid.