The thyroid gland consists of two lobes connected by a thin bridge of tissue called the thyroid isthmus. It somewhat resembles a large butterfly facing downward towards the chest. It usually lies below and anterior to the larynx.
The thyroid gland helps to maintain the optimum level of metabolism in the body and also plays critical role in brain development of babies. It produces the hormones T3- triiodothyronine, T4-thyroxine and calcitonin. It is not essential for life but both its absence and over activity leads to different diseases.
Thyroid diseases can be broadly divided into the following categories (However, it should be noted that the following conditions may overlap with each other):
- Hyperthyroidism- Diseases associated with excessive release of thyroid hormone
- Hypothyroidism – Diseases associated with thyroid hormone deficiency
- Mass lesions of the thyroid gland – Goiter, thyroid cancer.
- Inflammation of the thyroid gland – thyroiditis.
It is also known as thyrotoxicosis. Here, excessive production of T3 and T4 leads to a hypermetabolic state with an increased basal metabolic rate from +10 to +100. A hyperthyroid person is jumpy, restless, may consume a lot of food without gaining weight and usually actually suffers from weight loss, despite the increased appetite. The skin is soft, warm and flushed due to increased blood flow. Sweating is also increased. Palpitation is one of the earliest and most prominent features of hyperthyroidism. Some thyrotoxic individuals may eventually develop heart failure called hyperthyroid cardiomyopathy. This means that when you extend your fingers, a slight tremor can be seen in the hands. In 60-80% of the cases, protrusion of the eyeballs occurs. This is called exophthalmos or thyroid eye disease. The bones of these individuals are weak. There is also an increased risk of fracture in individuals with long-term untreated hyperthyroidism.
Some common causes of hyperthyroidism are:
1. Grave’s disease (most common – 60-80%)
2. Toxic multinodular goiter
3. Solitary Toxic adenoma
Hypothyroidism is actually the opposite of hyperthyroidism. With hypothyroidism, inadequate production of thyroid hormones tends to make a person feel drowsy and sluggish, overweight even though their appetite is decreased and, in general, leads to chronic fatigue. The person also suffers from poor memory and mental sluggishness which may mimic depression. It is a fairly common condition and its prevalence increases with age.
If hypothyroidism develops in an older child or adult, it is called myxedema. A fun fact about myxedema is that it is the only disease that can be diagnosed over the telephone, because the voice of these individuals is husky and slow. The basal metabolic rate may fall to about 40%. The skin is dry, yellowish and cold.
If hypothyroidism develops from birth, or before, then it is called cretinism. Worldwide, congenital hypothyroidism is one of the most common causes of preventable mental retardation and it is most often caused by endemic iodine deficiency in the diet. Children who suffer from cretinism are called cretins. The term cretin came from the French chretien, which means “Christ like” and was applied to these unfortunate children because they were considered too mentally retarded to commit any sin. These children are dwarfed and have a protruding tongue. If treatment is started at birth then normal physical growth can be achieved and mental retardation can be usually avoided.
Some causes of hypothyroidism:
- Maternal iodine deficiency
b. Fetal thyroid dysgenesis
c. Inborn errors of thyroid hormone synthesis
- Spontaneous atrophic
- Post-surgery and post- irradiation
Enlargement of the thyroid gland is called a goiter. The most common cause of goiters is a lack of iodine in the diet. That is why most commercial table salt is iodized. Goiters can be briefly divided into:
- Diffuse goiter
Here the entire thyroid gland is enlarged without any nodularity. This type of goiter is divided into two types: endemic goiter and sporadic goiter.
An endemic goiter occurs in areas where the soil, water and food contain low levels of iodine. When more than 10% population in a given region suffers from goiter, it is called endemic goiter. It can also be caused by eating certain food which contain substances – called goitrogens – that interfere with thyroid hormone synthesis. Goitrogens are present in vegetables such as cabbage, cauliflower, Brussels sprouts, turnips and cassava.
Sporadic goiter is less common than endemic goiter. It occurs more commonly in females usually during puberty or young adult life.
- Multinodular goiter
Irregular enlargement of the thyroid gland is called multinodular goiter. These goiters are derived from chronic diffuse goiters and as such, they have both endemic and sporadic components.
Usual presentation of thyroid cancer is a single or solitary thyroid nodule. Fortunately, the majority of the solitary nodules are either non-cancerous or benign. There are certain clinical features which determine the nature of a thyroid nodule:
- Solitary nodules are more likely to be cancerous than multiple nodules. Even though only about 1% of solitary nodules are malignant, it still represents about 15,000 new cases of thyroid cancer per year in the U.S.
- Young patients are more likely to develop cancerous nodules than older patients.
- Male patients are more likely to have cancerous nodules than females.
- Nodules that take up radioactive iodine (hot nodules) are usually benign.
Thyroid cancer can be classified as:
- Papillary carcinoma – most common
- Follicular carcinoma
- Anaplastic carcinoma
- Medullary carcinoma
Inflammation of the thyroid gland is called thyroiditis. A variety of diseases can cause thyroiditis. These diseases are:
- Infections thyroiditis
- Hashimoto’s thyroiditis
- Subacute granulomatous thyroiditis / De Quervain thyroiditis
- Subacute lymphocytic thyroiditis / Painless thyroiditis
- Fiborus thyroiditis / Reidel thyroiditis
With a plethora of diseases linked to thyroid function, it is important to have a strong snapshot of your thyroid health. The best way to avoid thyroid disease is education and prevention. So come into Pinnacle Integrative Health to receive a thorough thyroid exam, your body will thank you long-term.