What is thyroiditis?
Thyroiditis is an inflammation of the thyroid gland. There are three main types of thyroiditis:
- Viral or sub-acute thyroiditis
- Postpartum thyroiditis
- Autoimmune thyroiditis
The first two of these are temporary and the thyroid usually but not always returns to normal. The third type can lead to permanent thyroid damage.
Viral or sub-acute thyroiditis
What is viral or sub-acute thyroiditis?
This is believed to be caused by a viral infection of the gland, usually associated with ‘flu-like’ symptoms. No single virus has been identified as the cause. It seems likely that several different viruses may be responsible. It is more common in women than men, most often affecting those aged 20-50.
What are the symptoms of viral or sub-acute thyroiditis?
The main feature is an enlarged thyroid gland that also feels painful or tender. You may have a sore throat, flu-like symptoms and/or fever. There is a phase of over-activity (hyperthyroidism) when you may have symptoms such as nervousness, tremor, palpitations, insomnia and feel warmer than usual, sometimes followed by a phase of under-activity (hypothyroidism) when you may experience the opposite symptoms, such as, slowness, fatigue and feeling colder than usual.
How is viral or sub-acute thyroiditis diagnosed?
By a physical examination and blood tests. Your doctor may also arrange for a radioisotope iodine uptake scan to rule out other causes of thyroid over-activity. If the uptake is low this confirms the diagnosis.
What is the treatment for viral or sub-acute thyroiditis?
In some patients, sub-acute thyroiditis resolves rapidly without treatment, or with the help of anti-inflammatory drugs. If, however, you have persistent pain and other symptoms, a short course of steroids may be needed. This is a highly effective treatment. Because the steroids are normally given for only one or two months, at a gradually reducing dosage, any side effects such as weight gain are minimal.
What is the outcome?
People usually recover completely in two to five months although in about five percent of cases there may be permanent under-activity. Should this happen you will be prescribed levothyroxine (synthetic thyroxine) tablets to replace the missing thyroid hormone.
What is postpartum thyroiditis?
This is a form of usually temporary thyroiditis that occurs after pregnancy especially in women with thyroid autoantibodies. It usually shows up in the first six months after giving birth.
What are the symptoms of postpartum thyroiditis?
Your thyroid may be a little swollen, but it is almost never painful. As with sub-acute thyroiditis it usually starts with symptoms of an over-active thyroid (hyperthyroidism) that may resolve by itself, or progress to symptoms of an under-active thyroid (hypothyroidism).
How is postpartum thyroiditis diagnosed?
By a physical examination and by blood tests for thyroid hormones and for thyroid autoantibodies. It is important to distinguish hyperthyroidism due to thyroiditis from Graves’ disease and an antibody test can help with this. A low uptake on the radioisotope uptake scan will help to confirm the diagnosis and can be performed safely with the minimum of interruption to breast-feeding.
What is the treatment for postpartum thyroiditis?
In mild cases there may be no need for treatment, as it may clear up quickly. If the hyperthyroid symptoms are troublesome, you may be prescribed a beta blocker drug to relieve them. If on the other hand the hypothyroid symptoms are a problem, you will need to take levothyroxine tablets. Neither treatment interferes with breast-feeding.
What is the outcome?
Most women have a complete recovery. If you are taking levothyroxine you can usually stop taking these tablets after six to 12 months. If, however, blood tests reveal abnormalities more than a year after the birth, these changes are not likely to resolve of their own accord and you will need further treatment.
Postpartum thyroiditis often returns after subsequent pregnancies, so it is important to have your thyroid tested after each birth, usually after two to three months. Because postpartum thyroiditis increases the risk of permanent thyroid disease in the future, it is advisable to have regular blood tests once a year to check thyroid hormone levels.
What is autoimmune thyroiditis?
This is a self-destructive process in which the body’s immune system attacks the thyroid cells as though they were foreign cells. Mild thyroiditis may occur in up to 20% of otherwise healthy women (men have a four- to ten-fold lower frequency of thyroiditis). The autoimmune process progresses to cause ill-health in only a small proportion of these people (about 10% of those with thyroiditis). The most common form of autoimmune thyroiditis is known as ‘Hashimoto’s thyroiditis’.
What are the symptoms of autoimmune thyroiditis?
Typical features are developing thyroid failure (hypothyroidism) and, sometimes, painless thyroid enlargement (goitre).
How is autoimmune thyroiditis diagnosed?
This is done by measuring antibody levels. If present, a blood test for thyroid hormones can determine the exact extent of damage. Sometimes typical features can be seen on ultrasound of the thyroid too. Blood tests may also predict if thyroid failure is likely to occur, in which case follow-up testing or treatment is usually advised.
Autoimmune thyroiditis tends to run in families and if there is a strong family history, screening of individual members for thyroid antibodies may be carried out.
What is the treatment for autoimmune thyroiditis?
If your thyroid has been damaged, you will need to take levothyroxine tablets to replace your thyroid hormones. (See: Your Guide to Hypothyroidism.)
Certain drugs may cause thyroiditis, including amiodarone, lithium, sunitinib, axitinib and interferons. In many cases the thyroiditis resolves without treatment. With other drugs such as amiodarone, steroid therapy may be necessary.
Some important points….
- Thyroiditis is not always permanent. It depends on what type you have
- A thorough evaluation by an endocrinologist will determine the type of thyroiditis. This may save you unnecessary treatment as many types require no treatment
- If you have had postpartum thyroiditis after one pregnancy, you should be tested after any further pregnancies
- Check with your doctor whether your prescription is exempt from charges
It is well recognised that thyroid problems often run in families and if family members are unwell they should be encouraged to discuss with their own GP whether thyroid testing is warranted.
If you have questions or concerns about your thyroid disorder, you should talk to your doctor or specialist as they will be best placed to advise you. You may also contact the British Thyroid Foundation for further information and support, or if you have any comments about the information contained in this leaflet.
The British Thyroid Foundation
The British Thyroid Foundation is a registered charity: England and Wales No 1006391, Scotland SC046037
The British Thyroid Association - medical professionals encouraging the highest standards in patient care and research
The British Association of Endocrine and Thyroid Surgeons - the representative body of British surgeons who have a specialist interest in surgery of the endocrine glands (thyroid, parathyroid and adrenal)
First issued: 2008
Revised: 2011, 2015
Our literature is reviewed every two years and revised if necessary.
© 2015 BRITISH THYROID FOUNDATION