The Basics of Thyrotoxicosis

Of the many thyroid disorders researched by scientists and health professionals through the years, hyperthyroidism is one of the more commonly occurring illnesses and one that has baffled and at the same time amazed researchers. One reason is that the symptoms mimic those from other common diseases making it difficult for the disease to be diagnosed. Another astonishing detail is how it is very similar, but also quite different from another disease called Thyrotoxicosis.

What is Thyrotoxicosis?

Thyrotoxicosis is the clinical term used to describe the circulation of excess thyroid hormones circulating in the body. Some research papers and journals use the term interchangeably with hyperthyroidism as they are both characterized to some extent by the “hyperfunctioning” of the thyroid gland.

The main difference, according to De Leo in their 2016 research shared by the US National Library of Medicine[1], is that thyrotoxicosis describes the excess in thyroid hormone with or without hyperthyroidism.

Having this disease means having low levels of Thyroid Stimulating Hormone (TSH) in the bloodstream. This happens when the pituitary gland thinks the level of thyroid hormone in the body is sufficient.

The most severe form of Thyrotoxicosis is called Thyroid Storm[2]. This is characterized by the dangerously high levels of blood pressure, body temperature, and heart rate of an individual with Thyrotoxicosis that has been left untreated.

Causes of Thyrotoxicosis

Virginia Mason Medical Center[3] has labeled hyperthyroidism not as an equivalent to thyrotoxicosis, but the leading cause of it since the disease is brought about by the presence of too much thyroid hormone in the thyroid gland.

Graves’ disease, the most common cause of hyperthyroidism, is also a cause of Thyrotoxicosis. Another probable cause for thyrotoxicosis would be Thyroiditis, as the inflammation of the gland triggers an excess of thyroid hormones to flow through the body.

Taking thyroid medication is an often overlooked cause of the disease as it is primarily seen as a cure for other pre-existing thyroid disorders. However, taking thyroid medication in excess can bring about too much thyroid hormone in the bloodstream even when the thyroid gland in itself is not overactive.

Symptoms of Thyrotoxicosis

Since thyrotoxicosis is an effect of too much thyroid present in the bloodstream, it causes an increase in the metabolic rate. The Society of Endocrinology[4] explains that symptoms of thyrotoxicosis may include, but is not limited to, diarrhea, tremors most notably in the hands, increased hear rate, and other similar symptoms of hyperthyroidism.

Symptoms of Graves’ disease such as bulging of the eyes (thyroid eye disease) and swelling of the fingertips are also considered as symptoms of Thyrotoxicosis.

Possible Treatment for Thyrotoxicosis

Treatment to this disorder, like in most thyroid diseases, depends on the age, severity, and other conditions a patient already has. If left untreated, thyrotoxicosis can lead to complications such as osteoporosis and heart rhythm disturbances. Possible treatments range from taking medications to Radioactive Iodine Therapy to surgery, as described by Dr. Jackie Gilbert of King’s College in London in her paper[5].

Thyrotoxicosis due to Graves’ disease may be treated with Radioactive Iodine Therapy. Care must be observed in this treatment as larger doses may result to hypothyroidism but it is otherwise a go-to remedy.

Surgery is advisable for those with more severe manifestations of thyrotoxicosis and if these patients have not responded well to other treatments. Patients must be checked for a normal working thyroid pre-surgery to reduce the risk of a thyroid storm.


[1] Leo S. D., Lee S. Y., Braverman L. E. (2016 March 30). Hyperthyroidism. Retrieved from

[2] Doheny K. (2018 January 16). Thyroid Storm: What to Know. Retrieved from

[3] Virginia Mason Medical Center. Thyrotoxicosis. Retrieved from:

[4] Society of Endocrinology. (Updated 2018 March). Thyrotoxicosis. Retrieved from

[5] Gilbert J. (2017).  Thyrotoxicosis – investigation and management. Royal College of Physicians. Retrieved from

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