Hyperthyroidism: What Are Its Risks, Causes and Stages?

Within the human body is a multitude of glands with an exponential number of purposes. They are divided into two categories called the endocrine and exocrine glands.

Endocrine glands are responsible for the disbursement of hormones, and among these is the thyroid gland. Along with metabolism, this specialized butterfly-shaped gland affects growth and development.

When it malfunctions, people experience dysregulation of thyroid hormones, leading to problems with digestion, nutrient absorption, emotions, temperature, sexual health and more.

What is hyperthyroidism?

The two primary hormones produced by the thyroid gland are triiodothyronine (T-3) and thyroxine (T-4). To maintain homeostasis, the thyroid gland releases specific amounts of these hormones into the bloodstream. Sometimes, however, it produces an incorrect output, resulting in either hypothyroidism or hyperthyroidism.

"Hyperthyroidism is a common issue where the thyroid operates in overdrive and overproduces the thyroid hormone," said Mandy Armitage, M.D., the Westfield, Indiana-based medical director of editorial services for GoodRx. "These hormones regulate many important bodily functions, so an imbalance can have a big impact on daily life."

Hyperthyroidism can lead to a set of signs and symptoms known as thyrotoxicosis, according to Sarah Musleh, M.D., an endocrinologist and co-founder of Anzara Health in Miami. Though both are attributed to elevated hormone levels, they are not synonymous. Hyperthyroidism is a direct result of the thyroid itself having issues with hormone production and secretion, while thyrotoxicosis refers to elevated levels in general, regardless of the cause.

Risks and causes of hyperthyroidism

The most common cause of hyperthyroidism is Graves' disease, according to Armitage. It is an autoimmune condition that causes the thyroid to attack itself, triggering it to swell and release hormones. Thyroiditis—inflammation of the thyroid gland—is another frequent perpetrator and leads to hormone leakage in the bloodstream.

Hyperthyroidism can be caused by overactive thyroid nodules, which appear as lumps on the throat. Other causes of hyperthyroidism are rare and include an excess of thyroid hormone medication, diets high in iodine and benign tumors.

Gender is one of the primary risk factors for hyperthyroidism, according to Armitage and Musleh, as women are much more likely to be affected. Older women in particular are at risk for both hyperthyroidism that originates in the nodules and the condition in general.

Genetics is a factor, too, as people who have dispositions for hyperthyroidism or Graves' disease experience it at a greater frequency.

Autoimmune disease causes are more common in young women, and smoking increases the chances of disease development, Musleh said. A history of certain chronic illnesses such as diabetes and anemia is an additional risk factor.

Though uncommon, recently pregnant women can develop postpartum thyroiditis, but it usually resolves on its own.

What are the stages of hyperthyroidism?

There is a large variance in the advancement of hyperthyroidism.

"The way hyperthyroidism develops will depend on the cause of the inappropriately elevated level of thyroid hormone level in the body," Musleh said.

Blood tests that analyze T-3, T-4 and thyroid-stimulating hormone (TSH) levels are very revealing when determining both stage and type. For instance, a combination of high T-3 and T-4 with normal TSH levels may be indicative of early Graves' disease, while elevations in all three could be caused by TSH-induced hyperthyroidism.

In hyperthyroidism's early stages, symptoms may be mild or mistakenly attributed to other ailments. Frequent complaints are irregularities in weight, temperature, energy levels and heart rate. As hyperthyroidism progresses, its presentation increases in severity and further complications with other body systems occur.

Facts, stats, studies and history of hyperthyroidism

Thyroid problems were noted as early as 2697 B.C.E. in China, despite the English term "thyroid" itself not being established until 1656. "Hyperthyroidism" took longer to be recognized, being coined in 1907 by surgeon Charles H. Mayo, who studied exophthalmic goiter, aka Graves' disease.

Iodine treatment was recommended beginning in 1911, but iodine therapy wasn't largely endorsed until the 1930s.

Hyperthyroidism management is possible, but it is often lifelong, and its exact causes are not always easy to discern. Symptomatology may be equally ambiguous, and out of approximately 20 million Americans who have thyroid diseases, up to 60 percent don't know it. This is in part due to the condition mimicking other problems, such as those related to mental, sexual or gastrointestinal health.

In infrequent cases, hyperthyroidism is persistent and may suggest serious conditions, such as thyroid cancer.

Over the last 40 years, the American Thyroid Association has been paramount in the improvement of the understanding, diagnosing and treating of hyperthyroidism and Graves' disease. It has funded extensive research to develop thorough and early screening tools, along with efforts to identify the function of thyroid hormones, brain development and genetics in thyroid issues.

Researchers continue to develop treatments for thyroid disease complications. One of the latest is the newly approved medication teprotumumab (brand name Tepezza), which is used to prevent and treat thyroid eye disease (TED).

Myths, misconceptions and incidence of hyperthyroidism in cats and dogs

Despite its prevalence, many fallacies about thyroid diseases exist, several of which are related to treatment. Not every case necessitates treatment from an endocrinologist, but taking over-the-counter (OTC) medications independently is not advisable for alleviating ailments.

Medication and treatment adherence is important, even if the symptoms have dissipated, and this process isn't immediate—it often takes months. Some people will be medicated indefinitely, but depending on the cause, a doctor may be able to wean patients off medications.

Humans aren't the only species that can be affected. Cats and dogs are at risk, too, but cats are much more likely to develop the disease. Feline hyperthyroidism may progress slowly, and the most common symptoms are weight loss and increased thirst, appetite and urination.

As the condition worsens, cardiovascular, digestive and further urinary complications arise, and canines often experience the same afflictions. Animals with hyperthyroidism should undergo a thorough examination by a vet and, if the condition is detected, treatment options are nearly identical to those for humans.