Thyroid gland makes thyroid hormone, thyroxine which affects a person’s physical energy, their weight and their mood. It is located in the front portion of the neck. Thyroid gland takes iodine supplied by the diet and synthesizes thyroid hormone (1).

Among the energy regulating hormones thyroid hormone is the most important hormone. Thyroid hormone can increase the rate of metabolism and plays an important role in growth process.

Thyroid hormone thyroxine

Thyroid hormone is made from iodide and tyrosine, an amino acid. Thyroid hormone thyroxine is also called T₄ as it contains four iodine atoms. The active form of T₄ is T₃ which is also known as triiodothyronine and it formed by removal of one iodine atom from T₄ (2).

Thyroid stimulating hormone

The quantity of thyroxine secreted by the thyroid gland is regulated by thyroid stimulating hormone (TSH). TSH is secreted by pituitary gland which is present at the base of the brain. The amount of TSH pituitary gland releases into the blood stream depends on the amount of T₄. If there is less thyroxine being secreted by the thyroid gland then the TSH secreted will be more (2).

Hyperthyroidism

The functional disorders of thyroid are related to the gland producing too little thyroid hormone (hypothyroidism) or too much thyroid hormone (hyperthyroidism). Hyperthyroidism is a condition in which excess thyroid hormone is synthesized and secreted by the thyroid gland (3).

Hyperthyroidism can also be described as excessive concentration of thyroid hormones in tissues because thyroid synthesizes increased amounts of thyroid hormones, excessive release of already formed thyroid hormones or may be because of an endogenous or exogenous extrathyroidal source (4).

Symptoms reported by people who have hyperthyroidism

It is not necessary that everyone who has hyperthyroidism will have the same symptoms. Common symptoms seen in people who are afflicted with hyperthyroidism (3, 4, 5) are listed below

• Palpitations
• Tachycardia, increased heart beat
• Fatigue and weakness
• Tremor, trembling of hands
• Anxiety
• Disturbed sleep
• Weight loss but appetite is the same or may actually increase
• Heat intolerance
• Hyperpigmentation (especially face and neck)
• Sweating
• Polydipsia, increased thirst

Diagnosis

When a doctor suspects hyperthyroidism a blood test will be ordered. Serum thyroid stimulating hormone (TSH) will be measured as it has the highest sensitivity and specificity for diagnosing thyroid problems (3).

When the TSH levels are low it indicates an overactive thyroid gland producing excess of thyroid hormone. Low TSH levels occasionally indicate a problem with pituitary gland and it may result in secondary hypothyroidism (2). If the serum TSH is low subsequently further tests in which measure serum T₃ and T₄ are carried out to see if there is subclinical hyperthyroidism or overt hyperthyroidism (3).

Treatment for hyperthyroidism

Treatment of hyperthyroidism may involve antithyroid drugs, radioactive iodine ablation, and surgery. Antithyroid drug therapy is a conservative approach and the most commonly used form of treatment. But the relapse rate is high. The other two options are more definitive but they need lifelong therapy for hypothyroidism that follows those treatments.

The best treatment would be suggested by the doctor depending on several factors which are specific to the individual. It is suggested to follow the health providers directions to overcome the problem of hyperthyroidism.

References

1. Centers for Disease Control and prevention (2014). HTDS Guide – About Thyroid Disease: Section Summary.https://www.cdc.gov/nceh/radiation/hanford/htdsweb/guide/thyroid.htm
2. American Thyroid Association (2014).Thyroid Function Tests.https://www.thyroid.org/thyroid-function-tests/
3. De Leo, S., Lee, S. Y. and Braverman, L. E. (2016) Hyperthyroidism, Lancet (London, England). Vol. 388(10047).https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5014602/
4. Kravets, I. (2016) Hyperthyroidism: Diagnosis and Treatment, American Family Physician. Vol. 93(5).https://www.aafp.org/afp/2016/0301/p363.html#sec-3
5. Mayo Clinic (2018). Hyperthyroidism (overactive thyroid). https://www.mayoclinic.org/diseases-conditions/hyperthyroidism/symptoms-causes/syc-20373659