The most common conditions of the thyroid gland

Endocrinology is a medical specialty that deals with the diagnosis and treatment of hormonal disorders. The most common reason for an endocrinological consultation is diseases.

About the thyroid gland

The thyroid gland is the largest endocrine gland in the human body. It produces 2 hormones: T4 and T3, which have varied and important effects on all body’s systems: metabolism, cardio-vascular system, central nervous system, digestive system, respiratory system, etc. In Romania, according to statistical data from the National Institute of Public Health, the incidence (new cases) of thyroid diseases tripled between 2010 and 2016. This increase in the incidence can be explained also by the improvement of the patients’ access to the specialized medical services but also of the diagnostic tests.

Hypothyroidism

  • It represents an insufficient production of thyroid hormones. The most common cause of hypothyroidism is the iodine deficiency that is encountered in certain areas of Romania such as the sub-Carpathians and Moldova. In areas with sufficient iodine intake, the most common cause of hypothyroidism is chronic autoimmune Hashimoto’s thyroiditis whose insufficiently known causes involve genetic and environmental factors. About 1% of hypothyroidism cases are represented by a pituitary gland adenoma and in this case hypothyroidism is secondary.
  • Symptoms of thyroid hormone deficiency include: dry skin, changes in voice, excessive fatigue, weight gain, sleep disorders, muscle cramps, constipation, cold intolerance, menstrual cycle disorders, depression, psychosis, memory loss , but also decreased sodium level, heart failure, decreased heart rate, EKG changes, fluid around the heart and abdominal cavity.
  • The screening test for hypothyroidism and thyroid disease in general is TSH. Without treatment, hypothyroidism leads to heart and respiratory failure, coma and death.

Hyperthyroidism

  • It is characterized by an excess of thyroid hormones. Thyrotoxicosis is the term used for overactive thyroid hormones regardless of the cause. The prevalence (total number of cases) of hyperthyroidism is variable in the general population, being reported between 0.6% and 16%.
  • The most common causes of hyperthyroidism are Graves-Basedow , toxic adenoma (a node that produces excessive amounts of thyroid hormones), or multinodular toxic goiter the latter being more common in older patients and in areas with iodine deficiency. Hyperthyroidism can also be iatrogenic, caused by excessive doses of Levothyroxine, which is used for the treatment of hypothyroidism. Symptoms are multiple: asthenia, excessive sweating, weight loss, insomnia, hot intolerance, agitation, anxiety, psychosis, palpitations, difficulty in breathing, accelerated bowel movement, menstrual cycle disorders.
  • Hyperthyroidism may be the cause or an aggravating factor for some heart rhythm disorders, the most important of which is atrial fibrillation. If not treated properly, hyperthyroidism can lead to heart failure and heart rhythm disorders, both of which can be fatal.
  • Proper diagnosis and treatment are essential to reduce the risk of developing and worsening heart disease.

Both hypothyroidism and hyperthyroidism can have devastating effects on the health of the pregnant woman as well as the fetus. Thyroid hormones are essential for the normal development of the brain both in the womb and after birth. Untreated neonatal hypothyroidism leads to decreased IQ and is the cause for congenital cretinism. This is why newborns are screened for thyroid disease in the first days after birth.
Thyroid nodules

  • It is a common medical problem. The prevalence (total number of cases) is about 10%, but up to 68% percentages are reported in the literature.
  • Thyroid nodules, like most thyroid disorders, are more common in women and the elderly. Most nodules, 80-85%, are benign; the rest are malignant.
  • There are several types of thyroid cancer most commonly being the papillary type.
  • Thyroid nodules can be screened for clinical examination but are most commonly diagnosed with thyroid ultrasound . Not all nodules require puncture-biopsy. The diagnosis of benignity or malignancy is based on biopsy. There are 2 known risk factors for thyroid cancer: positive family history and exposure to ionizing radiation, especially in childhood.

References:

  1. Williams Textbook of Endocrinology 13th Edition, 2016
  2. American thyroid association guidelines for hypothyroidism,2014
  3. ATA guidelines for hyperthyroidism, 2016
  4. ATA guidelines for adult patients with thyroid nodules and differentiated thyroid cancer, 2016

Article made by Dr. Cristina Bloț, specialist in endocrinology

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