Hyperthyroidism occurs when an individual’s thyroid gland is overactive and produces excessive thyroid hormones.
What is a thyroid?
The thyroid gland is a butterfly-shaped gland found in the throat, sometimes likened to a bow-tie. It produces the thyroid hormones, triiodothyronine (T3) and thyroxine (T4), which have key roles in metabolism, growth and development.
Signs of hyperthyroidism may include:
- Goitre – a noticeable swelling of the thyroid gland.
- Palpitations – increased or irregular heart rate
- Skin changes – warm or moist skin, urticaria (hives), redness on the palms or hair loss (alopecia)
- Tremor – shaking or trembling of a part of the body
- Twitching of the face and/or limbs
- Mood swings – anxiety, irritability, nervousness and hyperactivity
- Weight loss
- Regular loose stools or frequent diarrhoea.
Recognising these symptoms will help you know when to refer suspected hyperthyroidism.
An example of a goitre, a swelling of the neck resulting from enlargement of the thyroid gland
Causes of hyperthyroidism
There are several causes of hyperthyroidism, for example:
Graves’ disease – the most common cause of hyperthyroidism (see box 1)
thyroid nodules – these are non-cancerous lumps that develop on the thyroid gland and account for one in 20 cases of hyperthyroidism
medication-induced – amiodarone, an anti-arrhythmia medicine, contains iodine – a precursor to hormones T3 and T4. It is known to cause amiodarone-induced hyperthyroidism
Iodine supplements – because of iodine’s role in the production of the thyroid hormones, supplements may raise hormone levels. In addition, those who have nodules on their thyroid gland and are taking supplements may get iodine-induced hyperthyroidism – sometimes called Jod-Basedow phenomenon
Cancer – this is the rarest cause of hyperthyroidism. Typical symptoms include a sore throat, dysphagia (difficulties swallowing), and a hoarse voice that doesn’t get better after a few weeks.
Box 1: Graves’ Disease
This disease is an autoimmune condition in which the body’s immune system sees the thyroid tissue as toxic – resulting in an overproduction of thyroid hormones.
It is most common in women between the ages of 20 and 40 – although it affects both sexes and occurs at any age. The disease can run in families, so it is important to ask a patient about their family history if hyperthyroidism is suspected. In addition, smokers are at an increased risk of developing Graves’ disease, and so a medicines use review is an opportunity to promote smoking cessation.
Managing the condition
Treatment will usually be initiated under the supervision of an endocrinologist, who will assess the patient’s symptoms, conduct blood tests, and confirm the condition.
Treatment options include:
Thioamides – these common drugs include carbimazole and propylthiouracil. These treatments work by reducing the amount of thyroid hormones the gland can produce. It may take some time – up to eight weeks – until these hormones are returned to an acceptable level, at which point the doctor may alter the patient’s dosage. These drugs have specific warnings (see below).
Radioiodine treatment – this targeted therapy involves giving a patient a liquid or capsule of radioactive iodine, with the intention of shrinking the thyroid gland and reducing the amount of hormones produced. The radioactive iodine travels to the thyroid and is converted to T3 and T4. As the radioiodine moves to the thyroid cells, it spares healthy tissue. A course of thioamides may be given before radioiodine treatment, to speed up the relief of symptoms.
Beta-blockers – these can relieve some of the symptoms of hyperthyroidism, for example, palpitations, tremor and hyperactivity. However, they may cause fatigue, nausea and sleep disturbances, and should be avoided in asthmatic patients because of the risk of bronchospasm.
Surgery – a partial or full removal of the thyroid gland, known as a thyroidectomy, may be required if a person experiences recurrent cases of hyperthyroidism, or they cannot be treated by other means. Surgery is a permanent cure, however, if the entire thyroid is completely removed the patient will need to take thyroid medication – namely levothyroxine – for the rest of their life.
Anyone starting on these treatments for hyperthyroidism should be made aware there may be some side effects. It is important that you can recognise these side effects and are able to empower patients to look out for them.
One in 20 patients taking thioamides will experience itching of the skin and joint pain. This will normally wear off after a few weeks.
Patients on carbimazole and propylthiouracil should be monitored for the reduction of white blood cells, specifically neutropenia (the reduction of neutrophils) and agranularcytosis (the rapid reduction in white blood cells). Agranularcytosis is a rare side effect that affects one in 500 patients and can cause the following symptoms:
- Bleeding mouth or gums
- Shortness of breath
- Persistent cough
- Sore throat
- Mouth ulcers
- Facial flushing
Due a lowered immune system, the infection can spread quickly and causes sepsis, which may cause an increased heartbeat and breathing rate. A patient presenting with any of the above symptoms while taking thioamides should seek immediate GP advice or call NHS 111.
Lifestyle and self-care advice
When talking to patients undergoing treatment for hyperthyroidism, it is important to discuss their lifestyle and how to support themselves.
Eye care advice is important for anyone with hyperthyroidism. Eye lid retraction or lag may be a sign of thyrotoxicosis, and people with Graves’ disease may complain of:
- pressure behind the eyes
- double vision
- excess tear production
You should refer people with these symptoms to their GP, as they may need to see an ophthalmologist for further investigation.
You should also discuss a normal, balanced diet with the patient. There is no specific diet to follow, so a consultation is an opportunity to reinforce the benefits of eating plenty of fruit and vegetables, reducing sugar and salt intake, and avoiding iodine-rich foods or supplements (see box 2).
Box 2: Dietary advice
Diet can affect iodine levels and the absorption of thyroxine medication.
Any patient who is diagnosed with hyperthyroidism and smokes will benefit from quitting – especially as smoking contributes to eye-related complications.
How to help the patient control their condition
When discussing hyperthyroidism during an MUR, it is useful to check how far into their treatment the patient is, when their last blood test was and if they know when their next test is scheduled. This will help ensure they are monitored effectively.
Patients who start taking thioamides (such as carbimazole and propylthiouracil) will usually have blood tests every two to six months until their thyroid hormone levels are stable, and then every six to 12 months if they are taking treatment long-term.
Patients who have had radioactive iodine treatments or undergone surgery will normally be reviewed regularly, to begin with, and then have annual reviews.
What else should you look out for?
Unexplained mood changes are a symptom of hyperthyroidism and patients who experience these should be encouraged to discuss it with their GP or specialist. It may be helpful for patients to ask close family members or friends to tell them if they notice changes in their mood.
You can also suggest that patients keep a mood diary – you could recommend the NHS Moodometer app. This will help patients record how they are feeling, gauge factors which are influencing their mood, and prompt them to discuss any major changes with their doctor.
NHS Moodometer app
Further help and information
There is a hereditary link seen in hyperthyroidism. You could mention to patients that close family members should be made aware of the signs and symptoms of this condition, and seek medical advice or thyroid testing if necessary.
CKS guidance on hyperthyroidism