When a person's thyroid gland does not produce enough thyroid hormone, they are said to have an underactive thyroid or a condition known as hypothyroidism.
Though it is relatively common, some experts believe the condition may be under-diagnosed, particularly among men. It is important to know the symptoms and get hormone levels measured if a person suspects a thyroid problem. If left untreated, hypothyroidism can result in numerous complications in the long-term:
1. Heart disease
Studies have linked hypothyroidism to various complications such as irregular heart rhythm, increased levels of LDL cholesterol, and the build-up of fluid around the heart i.e. pericardial effusion.
"Hypothyroidism can result in decreased cardiac output, increased systemic vascular resistance, decreased arterial compliance, and atherosclerosis," stated a review from 2017.
This condition results in an enlarged thyroid gland, which is located at the base of the neck. This results in an abnormal swelling in that area, which can also cause breathing and swallowing difficulties. The swelling usually occurs when the thyroid is damaged by a deficiency or disease such as hypothyroidism, iodine deficiency, thyroid cancer, or Graves' disease.
According to UCLA Health, risk factors for goiter include female sex, age over 40 years, inadequate dietary intake of iodine, residence in an endemic area, and a family history.
3. Infertility and birth defects
"Low levels of thyroid hormone can interfere with the release of an egg from your ovary (ovulation), which impairs fertility," said Dr. Jani R. Jensen, a fertility specialist from the Mayo Clinic.
And infertility is not the only complication a reproductive-age woman may face. Thyroxine is important for the developing brain, especially during the first trimester of pregnancy. As a result, maternal hypothyroidism has been linked to a higher risk of birth defects, intellectual and developmental problems.
4. Mental health risks
The link between depression and hypothyroidism has remained poorly understood, although many have suggested the former to be a possible symptom of the latter.
"Mild, non-specific neuro-cognitive symptoms may be seen in subclinical hypothyroidism," said Dr. James Hennessey, an associate professor of medicine at Harvard Medical School. "Individuals with such symptoms deserve to have their thyroid function tested—and if they are clearly subclinical hypothyroid, levothyroxine therapy should be considered."
5. Problems during puberty
Children and adolescents with an underactive thyroid gland may face a number of problems such as delayed puberty, poor mental development, impaired school performance, irregular menstrual periods etc.
The standard treatment is levothyroxine, according to Dr. Andrew J. Bauer, medical director of The Thyroid Center at Children’s Hospital of Philadelphia. The synthetic replacement hormone helps by compensating for the thyroid gland, which is not producing hormones in adequate quantities. Dr. Bauer added levothyroxine may leave young patients with a lot more energy and mental sharpness, improving their academic performance as well as their physical activity levels.
6. Nerve damage
Peripheral neuropathy is often caused by diabetes but might also be triggered by hypothyroidism in uncommon cases. This disorder causes damage to the peripheral nerves, which are the nerves that connect the brain, spinal cord, and the rest of the body.
Although the link is still unclear, hypothyroidism can "cause fluid retention resulting in swollen tissues that exert pressure on peripheral nerves," according to Dr. Todd Nippoldt, a board-certified specialist in internal medicine and endocrinology and metabolism from the Mayo Clinic.