Hypothyroidism can be divided into three disorders:
Type 1 Hypothyroidism, whereby the thyroid gland does not produce enough thyroid hormone. It is easily detected by a thyroid panel blood test. This type of hypothyroidism only affects five percent of the population.
Type 2 Hypothyroidism occurs at the cellular level. While the thyroid gland produces sufficient amounts of hormone, the body’s cells are unable to utilize the hormone properly. It can be caused by thyroid receptors on the cells or in the cells being damaged and thereby not available for the thyroid hormone to bind to. This receptor problem can be inherited or can be caused by toxins in our environment. Very frequently, interaction of thyroid hormone and its target cell can be interrupted because of iodine deficiency. It’s the most common cause of hypothyroidism in the United States, affecting upwards of forty percent of Americans, primarily middle-aged women, but also men and women of any age, and children.
Type 3 Hypothyroidism, more commonly known as Hashimoto’s thyroiditis, is a condition in which your immune system attacks your thyroid. The resulting inflammation often leads to an underactive thyroid gland. Symptoms include weight gain, depression, mania, sensitivity to heat and cold, paresthesia, chronic fatigue, panic, bradycardia, hypoglycemia, constipation, migraines, muscle weakness, joint stiffness, menorrhagia, cramps, memory loss, vision problems, infertility, and hair loss. The laboratory work-up is the same as Type 1 and Type 2, but in addition, autoantibodies may be present against thyroid peroxidase and thyroglobulin. These are two important enzymes needed to convert the inactive T4 pro-hormone to the active T3 active hormone.
The other interesting nuance is that ninety percent of patients with Hashimoto’s disease have gluten intolerance. Knowledge of this aids in therapy by replacing the deficient hormones as well as placing the patient on a gluten-free diet.