Hypothyroidism
- disorders of the thyroid gland
Author: Bano Imam Afange

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.

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

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