Hashimoto's disease: symptoms, tests and how it is managed

Hashimoto's disease is a common cause of an underactive thyroid. Many people have no symptoms at first, and the condition can be managed with regular medical care. This article explains what the NIDDK and NHS say. It is general education and not a diagnosis.

What is Hashimoto's disease?

The NIDDK describes Hashimoto's disease as an autoimmune disorder in which the immune system attacks the thyroid, so the gland cannot make enough hormone. It usually causes hypothyroidism and rarely causes hyperthyroidism. It is also called Hashimoto's thyroiditis, chronic lymphocytic thyroiditis or autoimmune thyroiditis. The NHS says it is the main cause of an underactive thyroid in the UK, is most common in women and usually starts between ages 30 and 50.

Symptoms

Many people have none at first, according to the NIDDK. As the disease progresses, common hypothyroidism symptoms include:

• Fatigue and weight gain
• Trouble tolerating cold
• Joint and muscle pain
• Constipation
• Dry skin and thinning hair
• Heavy or irregular periods, or fertility problems
• A slowed heart rate

The thyroid may enlarge into a goitre, which can cause a feeling of fullness in the throat but is usually painless. After years or decades, the gland may shrink and the goitre may disappear, the NIDDK says.

Causes and risk factors

Researchers do not know exactly why Hashimoto's develops. The NIDDK says genes and viruses such as hepatitis C may play a role, and a family history of thyroid disease is common. Women are 4 to 10 times more likely than men to develop it, most often between ages 30 and 50. Other autoimmune conditions, including celiac disease, lupus, rheumatoid arthritis, Sjögren's syndrome and type 1 diabetes, raise the risk.

How is it diagnosed?

The NIDDK says doctors use a medical history, a physical exam including a check of the neck for a goitre, and blood tests for thyroid hormones (T4 and T3), TSH and thyroid peroxidase antibodies. If antibodies are absent but Hashimoto's is still suspected, an ultrasound of the thyroid may be ordered. An ultrasound can also rule out other causes, such as nodules.

Treatment

The NIDDK says treatment depends on whether hypothyroidism is present. Without it, doctors may simply monitor symptoms and hormone levels. When hypothyroidism is present, the recommended treatment is a synthetic thyroid hormone medicine. The NIDDK says blood tests are done 6 to 8 weeks after starting and after each dose change, then about every 6 months, then yearly once stable. It warns never to change the dose without your doctor, since too much can cause an irregular heartbeat or thinning bones. Some foods and supplements can affect how the medicine is absorbed, so ask your doctor or pharmacist.

Complications if untreated

The NIDDK says untreated hypothyroidism can lead to high cholesterol, heart disease and heart failure, high blood pressure, and, rarely, myxedema, a life-threatening condition in which body functions slow dangerously.

Iodine and diet

The NIDDK says people with Hashimoto's may be sensitive to iodine. Large amounts from seaweed such as kelp or dulse, iodine supplements, some iodine-rich medicines or certain cough syrups may cause or worsen hypothyroidism. It says vitamin D and selenium are being studied, but no specific guidance exists yet. Please check with your doctor before taking any supplement.

Pregnancy

The NIDDK says untreated hypothyroidism can cause pregnancy problems. Pregnant people need enough iodine, but too much can cause a goitre in the baby, so doctors should advise on iodine needs. The NHS says to tell your GP if you are pregnant or planning to be, since your dose will probably need adjusting.

When to see a doctor

See a doctor if you notice symptoms such as tiredness, feeling cold, weight gain, dry skin or a swelling in the neck. If you have another autoimmune condition, mention it. Contact your doctor right away if you become pregnant.

Seek emergency help for trouble breathing, a wheezing noise when breathing, extreme drowsiness, confusion or very slow breathing. In an emergency, call your local emergency number (112 in India, 911 in the United States).

This article is for education only and does not replace advice from your own doctor.