Understanding Hyperthyroidism and Hypothyroidism
According to the World Health Organization (WHO), thyroid disorders are very common, affecting a staggering figure of roughly seven hundred and fifty million individuals worldwide. With such a high number of individuals affected by thyroid disorder, it is important to bring attention this ailment.
With this statistic in mind, lets have a look at a scenario. Mrs. Samornsri is a thirty-two-year-old female. Today she visited her primary care physician complaining of weight loss, occasional diarrhea, palpitations, and heat intolerance. She went on to explain that her symptoms have been going on for roughly 3 months. Mrs. Samornsri works as a sales executive for a large import and export company. She travels often for business but denies any pressure from her job. In fact she professes her love of her profession and the chance of being able to work with people from all over the world. She is happily married and enjoys playing badminton with her husband three times a week. While noting her medical history, her physician asks how many cups of coffee she consumes per day. This is a critical question to ask during this stage of the interview as too much caffeine can mimic some of the symptoms she is presented with, such as palpitation or restlessness. Mrs. Samornsri promptly replied that she does not drink tea or coffee and that she often eats clean foods and believes that she leads an active and healthy lifestyle. During the physical examination her physician notices that she seems a little bit restless. Her skin appears moist on examination. Her hair appears fine and thin. Mild hyper-reflexia (over responsive reflex) is observed throughout her joints upon stimulation. On chest auscultation, her heart sound appears normal without any murmur, but there is a clear indication of tachycardia (increased heart rate, over 100 beats per minute). On examination of her eyes, Mrs. Samornsri shows minimal symptoms of exophthalmos (bulging eyes) and proptosis (eyelid retraction). With the results of Mrs. Samornsri’s physical examination coupled with her chief complaint and medical history, her physician has a strong clinical suspicion that she has hyperthyroidism (specifically Graves' disease as exopthalmos and proptosis is unique to this specific type of hyperthyroidism). The physician shares his clinical suspicion with Mrs. Samornsri and orders investigative tests that include a blood draw of TSH (thyroid stimulating hormone) to assess the function of her thyroid gland. Furthermore, in addition to rescheduling her for a revisit to the office in two days to review her blood work and treatment plans, he prescribes propranolol, a type of beta-blocker, to control her palpitation and restlessness symptoms. Two days later Mrs. Samornsri returns to meet with her physician. He shares with her the blood results that confirm his suspicions that her symptoms are a result from a form of thyroid disorder termed hyperthyroidism. He goes on to explain that the thyroid gland is the metabolism regulator headquarters of our body, hence an important vital system. Basically, a hyperthyroid means an increase in thyroid hormones to the bloodstream leading to all bodily processes being speed up. This process of an elevated metabolism is evident in her symptoms such as palpitation, an increased heart rate, weight loss, diarrhea, and restlessness. In contrast, hypothyroid on the other hand, is a condition where the thyroid gland does not produce enough thyroid hormones leading to the all bodily process being slowed down. Mrs. Samornsri thanks her doctor for explaining the function of the thyroid gland and affected hormones, and how treatment and management is vital in maintaining her body homeostasis. She takes a closer look at her blood work report again and asks her doctor about the meaning of low TSH and elevated T4 on the lab report. Her doctor explains that these values confirmed the diagnosis of hyperthyroidism. T4 represents thyroid hormones while TSH (thyroid stimulating hormones) is an indication of the activity of the thyroid gland itself. In Mrs. Samornsri’s case, because of her condition of hyperthyroid, her thyroid hormones (T4) are elevated. Her thyroid gland senses this abnormality and tries to compensate by shutting down the thyroid gland in the hope of ceasing the production of thyroid hormones. This explains low TSH. Next, which type of hyperthyroidism does Mrs. Samornsri have and what are the treatment options? Could it be subacute thyroiditis? Subacute thyroiditis can be triggered by infections and usually can be treated with aspirin to relieve symptoms. This condition is unlikely in Mrs. Samornsri as she denies any recent infection or cold. Could it be silent thyroiditis? Silent thyroiditis usually resolves on its own and does not require any form of treatment. As mentioned before, her physician has strong suspicions that her type of hyperthyroidism is Graves' disease, since during the initial physical examination of Mrs. Samornsri she exhibits two distinct physical findings distinct to Graves' disease (exophthalmos – bulging eyes and proptosis – eyelid retraction). The doctor orders a radioactive iodine uptake test which will clearly differentiate the diagnosis of Graves' disease, as the result will indicate elevated uptake as opposed to a low uptake characteristic of silent thyroiditis and subacute thyroiditis. As expected Mrs. Samornsri’s results indicates elevated radioactive iodine uptake, confirming the diagnosis of Graves' disease. Treatment for Graves' disease type of hyperthyroidism as in Mrs. Samornsri's case is to simply decrease the elevated thyroid levels by hormone management. Her doctor explains the treatment plan and prescribes radioactive iodine medication for her to take orally. The idea is that radioactive iodine pills will be absorbed by her thyroid gland shrinking and eventually ablating the gland altogether. Mrs. Samornsri understands the treatment plan and expresses her excitement that steps are being taken for her to recover and to again enjoy both her family life as well as work life. One month later Mrs. Samornsri returns to the office for a check up. She is happy to report that she no longer experiences any of her symptoms from her initial office visit such as weight loss, palpitation, and diarrhea. In spite of this, she goes on to explain that now she is experiencing symptoms that are opposite to her original complaints. She has gained weight, has experienced constipation, her skin feels dry and she feels tired all the time. Her doctor reassures her that this what he had expected from the treatment of Graves' disease. He explains to her that he suspects that the radioactive iodine medication has ablated her thyroid gland in turn treating her hyperthyroid condition. In spite of this, the treatment has caused a hypothyroidism state in her as a result of the destruction of her thyroid gland leading to decreased thyroid hormone production causing her metabolism rate to decline. He promptly confirms the diagnosis with a blood test, showing her TSH levels elevated and her T4 suppressed. He explains that this lab result is due to her having low thyroid hormone which is evident by the low T4 level, while her TSH (thyroid stimulating hormone) is elevated in a physiological response as it tried to signal to the thyroid gland to produce more thyroid hormones. Her doctor reassures her and prescribes her a medicine called levothyroxine, a synthetic thyroid hormone, and asks her to return in three weeks for a follow up and blood work. His hope is that this medication will act as a substitute for her thyroid hormones and decrease her TSH level, returning her body from hypothyroidism to homeostasis state. Three weeks later Mrs. Samornsri returns for a check up and blood work. Her blood work shows that her TSH and T4 levels are in normal range. Furthermore, she expresses her delight in feeling well again. She shares with her doctor that she has won the local badminton tournament at the YMCA over the past weekend!
