Hypothyroidism

- disorders of the thyroid gland

Author: Bano Imam Afange

KEMSA Hypothyroidism

Metabolism and the thyroid

So, the thyroid gland is responsible for the metabolism of the body. By metabolism, I mean the reactions happening in our body to form what we call energy. Energy is what keeps organisms in activity in order to live. The energy is also used to build, repair and defend the cells within the body. The thyroid gland does it by secreting two hormones, Triiodothyrinine (T3) and Thyroxine (T4), in cooperation with the hypophysis - a gland located at the base of our brain. Increased levels of the hormones T3 and T4 causes increase in metabolism, while lower levels will cause a decrease.

KEMSA Hypothyroidism

Hypothyroidism

When a person has hypothyroidism, they will have decreased metabolism due to lower levels of
the hormones T3 and T4. The causes of this condition can be categorized to

  • Autoimmune destruction of the thyroid gland (Hashimoto)
  • Surgery on the gland
  • Radioiodine exposition (medically or environmental)
  • Viral infection
  • Certain medications such as amiodarone, lithium, interferon-alpha and interleukin-2
  • Treatment of cancer in the neck area with radiation
  • Too little iodine in the diet
  • Secondary due to the hypophysis gland

The autoimmue cause of hypothyroidism is a condition called Hashimoto, and is due to antibodies against certain proteins involved in the formation of the thyroid hormones. These antibodies attack thyroid peroxidase (TPO) and thyroglobulin (TG), thereby destroying the gland and its function. Although not so common, subacute thyroiditis can causes both hyperthyroidism and hypothyroidism. There is not much known about this disease, but evidence suggest upper respiratory tract infection due to a viral etiology. There are four types of subacute thyroiditis:

  • Subacute granulomatous thyroiditis (De Quervain thyroiditis)
  • Subacute lymphocytic thyroiditis
  • Postpartum thyroiditis
  • Palpation thyroiditis
KEMSA Hypothyroidism

The risk of getting hypothyroidism increases with

  •  Race (being white or Asian)
  • Increasing age
  • Autoimmune disorders
  • bipolar disorder
  • Down´s syndrome
  • Turner syndroms

The many symptoms are caused by the decrease in metabolism, which slows down many reactions in the body. The following is a list of common symptoms

  •  feeling more tired and sleepy
  • depression
  • a decrease in concentration
  • drier skin
  • sensitivity to cold tempratures
  • constipation
  • increase in weight
  • change in menstrual cycle
  • fatigue
  • slower heart rate

The Diagnosis

 

Your doctor will run a few tests to find out if you have hypothyroidism, which include

  • blood test for the hormones Thyroid stimulating hormone (TSH), T3 and T4, in which TSH levels
    will be increased, T3 normal and T4 decreased
  • Ultrasound vision the thyroid gland
  • Thyroid scintigrpahy to check the activity of the gland
  • ECG

The Treatment

 

Patients with hypothyroidism receive a synthetic thyroxine hormone which increases the levels of T4, and restores the metabolism back to normal. The patient will keep this treatment throughout his/her life. Usually the patient are started (especially the elderly) on small doses of the medication due to complications such as heart disese. However, higher levels of the medication can be needed in pregnancy, further destruction of the thyroid gland and due to interactions with other medications.

Sources

Hans Kornberg (2017, September 15). Metabolism. Retrieved from https://www.britannica.com/
science/metabolism

Bridged Brady, MD, FACS (2017, July 4). Thyroid Gland, how it functions, symptoms of
hyperthyroidism and hypothyroidism. Retrieved from

https://www.endocrineweb.com/conditions/
thyroid-nodules/thyroid-gland-controls-bodys-metabolism-how-it-works-symptoms-hyperthyroi

Laura J. Martin, MD (2017, August 13). Hypothyroidism (Underactive thyroid). Retrieved from
https://www.webmd.com/women/hypothyroidism-underactive-thyroid-symptoms-causestreatments#
3

n.d. (2016, December 15). Subacute thyroiditis. Retrieved from https://en.wikipedia.org/wiki/
Subacute_thyroiditis

http://www.meded.co.za/Category/2244

https://www.thyrogen.com/patients/About-Thyroid-Cancer/Your-Thyroid.aspx

https://www.verywellhealth.com/how-to-tell-if-you-are-hypothyroid-3231726