Our last newsletter covered the role of the thyroid and hypothyroidism. Today’s newsletter is going on to talk about the opposite, what happens when the thyroid gland produces too much hormone?

What is hyperthyroidism?

This is a condition occurring when there is a production and secretion of excessive amounts of thyroid hormone in the body.

What are the symptoms?

In hyperthyroidism there is an increased metabolism of all the body systems. This leads to symptoms such as:

• Nervousness, irritability and anxiety 😥 

• Mood swings

• Sensitivity to heat or persistent sweating 🥵 

• Difficulty sleeping 😴 

• Swelling in the neck due to an enlarged thyroid gland (goitre)

• Irregular and/or unusually fast heart rate ❤️

• Twitching or trembling

• Persistent tiredness and weakness

Treatment options

There are 3 types of treatment option:

1. Anti-thyroid drugs

2. Radioactive iodine

3. Surgery (partial thyroidectomy)

Anti-thyroid drugs

These are drugs which prevent synthesis of thyroid hormones.

Carbimazole

This is the most commonly used anti-thyroid drug. Initial dose is 15-40 mg daily and is progressively reduced to a maintenance dose of 5-15 mg daily.

As this medicine prevents synthesis of thyroid hormone, a patient must be given levothyroxine as well to replace thyroid hormone.

Before therapy commences, a full blood count (FBC) and liver function tests (LFT) must be carried out.

Side effects of carbimazole treatment include neutropenia (very low levels of neutrophils) and agranulocytosis. Carbimazole suppresses bone marrow where white blood cells (WBCs) are produced. A patient given this medicine should therefore report signs and symptoms of infection, especially a sore throat. A WBC count should be taken if there is clinical evidence of infection. Treatment should be stopped promptly if there is any clinical or lab evidence of neutropenia.

The usual treatment length for carbimazole is 12-18 months; however, some people may relapse and have issues again so they may need to go back on carbimazole treatment.

Propylthiouracil

This is an anti-thyroid drug used when a patient is sensitive to carbimazole. The initial dose is 200-400mg daily then reduced to a maintenance dose of 50-150mg daily.

Beta-blockers

These medicines don’t treat the underlying disease but rather rapidly relieve the symptoms such as palpitations, anxiety, sweating and tremor. They are used as an adjunct to radioactive iodine and carbimazole in the first few weeks of treatment. Propranolol is commonly used at a dose of 10-40 mg 3-4 times daily.

Monitoring anti-thyroid drugs

• Measure TSH, FT4 and FT3 every 6 weeks until TSH is within the reference range, then

• Measure TSH every 3 months (with cascading) until anti-thyroid drugs are stopped.

Radioactive iodine

This is a safe treatment which leads to most patients becoming hypothyroid. Although, it is contraindicated in children, pregnancy and breastfeeding 🤱.

Surgery (thyroidectomy)

This is a surgery which involves removing part of the thyroid gland to restore normal thyroid levels in the body. Patients receiving this surgery should take radioactive iodine 10-14 days before the surgery.

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