Ask the Doctor: ‘I’ve been experiencing heart palpitations lately, along with a sudden loss of weight and changes in my cycle. Could these be symptoms of hyperthyroidism?’

“I’ve been experiencing heart palpitations lately, along with a sudden loss of weight and changes in my cycle. Could these be symptoms of hyperthyroidism?”

Answer from Dr Carla Moran FRCPI PhD Consultant Endocrinologist at the Beacon Hospital

Yes, these symptoms may well be due to hyperthyroidism, a condition where the thyroid gland produces too much thyroid hormone. The thyroid gland is a butterfly shaped gland that sits in the front of our neck. Its role is to produce thyroid hormone, which circulates around the blood stream and has an effect on almost every part of our body, including our
muscles, heart, brain, liver and bones.

Thyroid diseases are very common, especially in women. The most common problem is thyroid gland under-activity, also called “hypothyroidism”, or an “under-active” thyroid gland. This happens because the gland is making too low a level of thyroid hormone. Thyroid gland overactivity, also termed “hyperthyroidism” or “thyrotoxicosis” is also quite common, especially in women. We are more than 8 times more likely to develop it than men! We diagnose thyroid problems using blood tests, which your GP can perform.

Symptoms of hyperthyroidism include anxiety, irritability, awareness of our heartbeat (it is often fast or forceful), warmth, sweats, poor sleep, fatigue, restlessness, weight loss, weakness, tremor, more frequent bowel motions, altered menstrual cycle, neck swelling.

Hyperthyroidism can happen due to various reasons, but the most common causes include Graves’ disease, thyroiditis and thyroid nodules. Graves’ disease is named after the Irish doctor who described it over 150 years ago. It happens because the body makes a tiny protein, called an antibody, that instructs the thyroid gland to continually produce excessive amounts of thyroid hormone. It is more likely to occur in people whose relatives have thyroid disease and can be related to pregnancy and childbirth. Thyroiditis occurs due to irritation of the thyroid gland; the gland releases stored hormone and then usually recovers by itself. This can happen after pregnancy, a viral illness (including COVID) or an autoimmune disease. Thyroid nodules are lumps within the gland that produce too much thyroid hormone.

The key to treating hyperthyroidism is to understand the cause. Graves’ disease is managed with tablet medication, usually for an 18-month course. After this, 1 in 2 people never experience Graves’ disease again. If it returns later, treatment with tablets is required again and we consider other treatments, such as surgery to remove the gland or a special type of
treatment called “radioiodine”. Thyroiditis usually settles by itself, but sometimes medications are needed for a short time for the neck is painful, and we usually monitor the hormone levels to ensure they completely normalise. Nodules are treated with tablets too, but they never go away, so we often recommend other treatments, such as surgery or radioiodine. Radioiodine is a (usually) once off tablet treatment that delivers radiation activity to the thyroid gland and stops the overactivity.

Symptoms of thyroid disease resolve once people receive effective treatment, and it does not affect any other hormones in any way. If you are concerned about thyroid disease, the first port of call is your GP.

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