Hyperthyroidism (overactive thyroid): symptoms, causes, treatment
Hyperthyroidism happens when the thyroid makes more hormone than the body needs, speeding up many functions. This guide covers symptoms, causes, tests and general treatment options.
Scientist and Chief Medical OfficerDr. Ambed Mishra, PharmD, PhDEducational information only, not medical advice. Always ask a qualified doctor about your own health. In an emergency call 112 (India) or 911 (US). Read the full disclaimer.
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When the thyroid gland makes more hormone than the body needs, many body functions speed up. This is called hyperthyroidism, or an overactive thyroid. It can usually be treated once the cause is found. This article explains the basics based on the NIDDK and NHS. It is general education, not personal advice.
What is hyperthyroidism?
The NIDDK defines hyperthyroidism as the thyroid gland making more hormone than the body needs. The NHS describes the common symptoms and notes that an endocrinologist, a hormone specialist, usually helps choose treatment.
Symptoms
The NIDDK lists:
- Weight loss despite a bigger appetite
- A fast or irregular heartbeat
- Nervousness, irritability, trouble sleeping and fatigue
- Shaky hands and muscle weakness
- Sweating or trouble coping with heat
- Frequent bowel movements
- An enlarged thyroid, called a goitre
The NHS adds anxiety, mood swings and neck swelling. The NIDDK says that in older adults, symptoms may look different, such as appetite loss or withdrawal, and can be mistaken for depression or dementia.
Causes
The NIDDK lists these causes:
- Graves' disease, the most common cause, which is an autoimmune disorder
- Overactive thyroid nodules, which are usually non-cancerous and more common in older adults
- Thyroiditis, which releases stored hormone
- Too much iodine
- Too much thyroid hormone medicine
- A rare, non-cancerous pituitary tumour
The NHS says Graves' disease accounts for about 4 in 5 cases, and names thyroid nodules and certain medicines as other causes.
Who is more at risk?
The NIDDK says hyperthyroidism is more common in women and people over 60. Risk is higher with a family history of thyroid disease, pernicious anaemia, type 1 or type 2 diabetes, primary adrenal insufficiency, high iodine intake, such as from kelp or iodine-containing medicines, nicotine use, and pregnancy within the past 6 months.
How is it diagnosed?
Doctors take a medical history, examine you and order thyroid blood tests and imaging, according to the NIDDK. Symptoms alone cannot confirm hyperthyroidism, because many conditions share them. The NHS says a blood test checks how well the thyroid is working, and further tests help find the cause.
Treatment options
The treatment depends on the cause, how severe it is, your age, pregnancy and other conditions, according to the NIDDK. A doctor decides which suits you. The NIDDK describes:
- Medicines: beta-blockers can ease symptoms such as tremor and rapid heartbeat but do not reduce hormone production. Antithyroid medicines reduce hormone production.
- Radioiodine therapy: destroys hormone-producing thyroid cells. It is not used during pregnancy or breastfeeding, and most people eventually develop hypothyroidism, which is managed with daily medicine.
- Surgery: used less often, for large goitres or for pregnant people who cannot take antithyroid medicine. Removing the whole thyroid means lifelong hormone replacement.
- Radiofrequency ablation: an emerging option for thyroid nodules that is not widely available yet.
Possible complications
If untreated, the NIDDK says hyperthyroidism can cause an irregular heartbeat that may lead to blood clots, stroke or heart failure, an eye condition called Graves' eye disease, thinning bones and muscle problems, and menstrual and fertility problems. The NHS warns of thyroid storm, a sudden and life-threatening flare-up of symptoms. The NHS also links poorly controlled or untreated overactive thyroid in pregnancy to pre-eclampsia, premature birth and miscarriage.
Medicine safety
The NIDDK advises calling your doctor right away if you are taking an antithyroid medicine and develop fatigue or weakness, dull abdominal pain, loss of appetite, skin rash, itching or easy bruising, yellowing of the skin or eyes, a constant sore throat, or fever or chills. Do not stop or change prescribed treatment without talking to your doctor.
When to see a doctor
See a doctor if you have symptoms, so that a blood test can be arranged. Ask about it if an older relative seems withdrawn or has a fast heartbeat, since symptoms can look different with age.
A sudden, severe worsening of symptoms, a very fast or irregular heartbeat, chest pain or confusion is an emergency. 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.
Common questions
What are the symptoms of an overactive thyroid?
The NIDDK lists weight loss despite a bigger appetite, a fast or irregular heartbeat, nervousness, sweating, shaky hands, frequent bowel movements and a goitre.
What causes hyperthyroidism?
The NIDDK says the most common cause is Graves' disease. Other causes include overactive nodules, thyroiditis, too much iodine and too much thyroid hormone medicine.
How is hyperthyroidism treated?
The NIDDK describes medicines, radioiodine therapy and surgery, depending on cause, severity, age and pregnancy. A doctor decides.
Can hyperthyroidism look different in older adults?
Yes. The NIDDK says older adults may have appetite loss or withdrawal, which can be mistaken for depression or dementia.
Important: please read
- Educational information only. This article is general health education. It is not medical advice, diagnosis or treatment. Reading it does not create a doctor–patient relationship with MyDoctor or with anyone else.
- Ask a qualified doctor. Always talk to a qualified, registered doctor about your own health. In India, that means a doctor registered with the National Medical Commission (NMC) or a State Medical Council. In the United States, a licensed physician. Elsewhere, a doctor licensed where you live.
- Never ignore or delay professional advice because of something you read here. Do not start, stop or change any medicine or treatment without your doctor.
- Emergencies: call 112 in India, 911 in the United States, or your local emergency number. Do not wait for an online answer.
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- About the sources. This article summarises, in our own words, information from the public health bodies named under Sources. Health knowledge changes, and this summary may not reflect the latest research or your personal situation.
- Liability. To the extent permitted by law, MyDoctor (MODERNUS HEALTH TECHNOLOGIES PRIVATE LIMITED) accepts no liability for any decision made on the basis of this content.
Sources
- NIDDK (NIH). Hyperthyroidism (Overactive Thyroid) www.niddk.nih.gov
- NHS. Overactive thyroid (hyperthyroidism) www.nhs.uk
- NIH MedlinePlus. Thyroid Diseases medlineplus.gov
Dr. Ambed Mishra, PharmD, PhD
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Dr. Ambed Mishra is a clinical (patient care) scientist, author and former professor. He is Group CEO and Chief Medical Officer of MODERN US HEALTH (MODERN US GROUP), Austin, Texas, the group behind MyDoctor, and a senior consultant who teaches and trains MD/DO physicians, PharmD and PhD professionals, nurses and other healthcare professionals in patient care in the United States and India.
More about Dr. Ambed Mishra
- More than ten years of full-time leadership in United States healthcare, building patient care services that improve medication adherence and bring doctors, pharmacists and nurses together around each patient.
- Leads the MD and engineering teams behind MyDoctor: clinic and hospital management software, electronic health records and telehealth for hospitals and physician groups in the United States and India.
- Former Assistant Professor and Clinical Preceptor at Rajiv Gandhi University of Health Sciences, Bangalore, and senior researcher with hospitals, universities and patient care groups in India and the United States.
- More than 30 published research and review articles and case reports, and more than 15 international conference presentations in India, Australia, Canada, the United States, Spain and other countries.
- Chief Medical Officer and Global Program Head of a nonprofit mission that helps cover hospital and doctor visit bills for patients in need in India, Nepal, the United States and other countries.
The author's office answers questions about articles, research, speaking and collaboration. It cannot give personal medical advice.