Roughly 1 in 100 Americans aged 12 and older has hyperthyroidism, according to the National Institute of Diabetes and Digestive and Kidney Diseases. Cleveland Clinic puts the US figure at about 1.3%.
The condition speeds up the metabolism. Its early signs look so much like anxiety, perimenopause or plain overwork that many people carry them for months before asking for a blood test.
The NIDDK notes that hyperthyroidism cannot be diagnosed from symptoms alone, because many overlap with other conditions. Still, a familiar cluster of warning signs tends to bring patients in.
The eight signs to watch for
1. Racing or pounding heart. Cleveland Clinic lists rapid heart rate and heart palpitations at the top of its symptom catalog. The NIDDK describes it as a rapid or irregular heartbeat.
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2. Weight loss with a normal or bigger appetite. Losing pounds you did not try to lose, even while eating more, is a classic sign flagged by the NIDDK.
3. Heat intolerance and sweating. The thyroid helps regulate body temperature. The NIDDK lists sweating or trouble tolerating heat, and Cleveland Clinic describes increased sweating and sensitivity to warm temperatures.
4. Anxiety, nervousness or irritability. The NIDDK lists nervousness, irritability, trouble sleeping and fatigue. This overlap is why the condition is so often written off as stress.
5. Hand tremors. The NIDDK includes shaky hands and muscle weakness. Cleveland Clinic phrases it as shakiness, like hand tremors.
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6. Hair thinning or brittle hair. Cleveland Clinic lists hair loss or brittle hair among typical symptoms.
7. Frequent bowel movements. The NIDDK lists frequent bowel movements, and Cleveland Clinic describes diarrhea or more frequent bathroom trips.
8. Lighter or missed periods. Cleveland Clinic notes menstrual period changes, like lighter or missed periods.
Two other signs sit outside the top eight. An enlarged neck, called a goiter, can develop, and in Graves' disease, bulging eyes and vision changes can occur.
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Why older adults get missed
The picture can look very different past 60. An Endotext chapter on hyperthyroidism in aging notes that older patients often present with "apathetic" hyperthyroidism, where the classic tremor and hyperactivity are absent. Cardiovascular symptoms, fatigue, weight loss, apathy or cognitive decline dominate instead.
The NIDDK adds that in older adults, hyperthyroidism is sometimes mistaken for depression or dementia.
The heart is the biggest concern. The same Endotext review states that atrial fibrillation complicates hyperthyroidism in about 15% of cases, at least three times more common than in people with normal thyroid function, and the incidence rises with age.
When to ask for a TSH test
The simplest first step is a blood test. According to the NIDDK's guide to thyroid tests, a low TSH usually means hyperthyroidism, because the pituitary eases off when the thyroid is already making too much hormone. TSH is the marker clinicians check first, and if it is abnormal, further testing follows.
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If you have several of the signs above at once, especially a racing heart, unexplained weight loss or a new tremor that has lasted more than a few weeks, ask your doctor whether a TSH test is warranted rather than waiting for the symptoms to pass on their own.
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This article is made and published by Jesper Bengtson, who may have used AI in the preparation.