Two Types of Thyroid Dysfunction
Two basic abnormalities can happen to the thyroid: 1) Structural thyroid disorders ("nodules and goiter") and 2) Functional thyroid disorders ("hyper" or "hypo"). The Texas thyroid endocrine specialists have briefly reviewed these aspects of the thyroid below. Based on a patient's symptoms and blood work results a patient may have either or both problems with their thyroid.
Functional Thyroid Disorders
The pituitary gland is a teardrop shaped gland of the brain that controls all the major hormones in the body. The relationship of the thyroid to the pituitary is called the hypothalamic-pituitary-thyroid axis. This axis works in a similar way to how a home thermostat functions. The primitive brain communicates with the the pituitary via thyroid-releasing-hormone (TRH). Assuming no pituitary tumors or malfunction, the pituitary gland communicates with the thyroid gland, located in the neck, via thyroid-stimulating-hormone (TSH). TSH tells the thyroid gland, located in the neck, to produce the thyroid hormones called thyroxine (T4) and tri-iodothyronine (T3). T4 and T3 are hormones that control the rates of many processes in the body, and they communicate via the blood with the brain to stop production of TSH and TRH. Thus, there is a delicate balance between the thyroid hormones and the brain to keep the body healthy. Problems in this system can be measured with thyroid function testing and can lead to functional thyroid abnormalities such as hypothyroidism and hyperthyroidism. There are two types of consequences to functional thyroid disease: subjective symptoms and objective sequelae. The clinical expression of thyroid hormone deficiency or excess varies significantly between individuals depending on the exact cause of hypothyroidism orcause of hyperthyroidism, severity of the symptoms, and duration of the dysfunctional thyroid state. Contact us to learn more about these types of thyroid conditions.
Structural Thyroid Disorders
The thyroid gland is a butterfly-shaped gland, made up of two halves called lobes. These lobes are located on both sides of the neck. The thyroid gland wraps around the front of the trachea (windpipe) just below the Adam’s apple. Located on either side of the thyroid are other nearby organs which include the parathyroid glands, the carotid arteries, the jugular veins, and the recurrent laryngeal nerve. Behind the thyroid is the esophagus (swallowing tube). In front of the thyroid are the strap muscles of the neck and the skin on top of those muscles. The thyroid is made up of two types of cells called follicular and parafollicular cells. The follicular cells produce the thyroid hormones (T3 and T4) that affects a person’s heart rate, body temperature and energy level. Parafollicular cells make a hormone called calcitonin that has only a minor role in helping the body maintain a normal level of calcium in the blood. Abnormal growth of these cells in the thyroid can cause structural thyroid disorders such as goiter, thyroid nodules, or thyroid cancer. Most patients have no symptoms, but if symptoms do occur they are related to the enlarged thyroid impeding the function of the other nearby organs in the neck. These symptoms are called compressive symptoms. There are no blood tests to diagnose structural problems. Instead, the endocrinologists at Houston Thyroid and Endocrine would need to use imaging testing such as ultrasound to diagnose these types of thyroid problems.