What Is Hypothyroidism?
The inappropriate secretion of TSH (thyroid-stimulating hormone) from the pituitary gland and thyroid gland's dysfunction facilitates the onset of hypothyroidism (Kostoglou-Athanassiou & Ntalles, 2010). Hypothalamus dysfunction leading to inappropriate TRH (thyrotropin-releasing hormone) also increases the risk of hypothyroidism and its clinical complications. Primary hypothyroidism is recognized under the following parameters:
- The decrease in FT4 (free T4)
- Increase in TSH
- Subclinical TSH (i.e., TSH elevation and FT4 normalcy
- Direct involvement of thyroid gland
Overt hypothyroidism in many nations reportedly occurs under the impact of salt iodination. Subclinical hypothyroidism in many scenarios remains asymptomatic or devoid of intense symptoms. Contrarily, clinical hypothyroidism leads to the development of intense symptoms that potentially elevate the risk of serious complications, including coma. The development of clinical hypothyroidism from subclinical hypothyroidism occurs under the impact of several conditions, including reproductive complications, neuromuscular symptoms, somatic manifestations, heart failure, and cardiovascular disease. Hypothyroidism also develops among the patients affected by neoplastic diseases under the impact of novel tyrosine kinase inhibitor therapy.
Secondary hypothyroidism is marked by the development of the following manifestations (Kostoglou-Athanassiou & Ntalles, 2010):
- Reduction in FT4
- Reduced or normal TSH
- Direct involvement of hypothalamus/pituitary gland
Thyroid hormone deficiency potentially triggers the development of hypothyroidism and its clinical manifestations (Kostoglou-Athanassiou & Ntalles, 2010). The categorization of hypothyroidism is majorly based on the following parameters:
- Congenital hypothyroidism (based on the time of onset)
- Acquired hypothyroidism (based on the time of onset)
- Primary hypothyroidism (based on endocrine dysfunction level)
- Central/secondary hypothyroidism (based on endocrine dysfunction level)
- Clinical hypothyroidism
- Subclinical/mild hypothyroidism
Causes of Hypothyroidism
Primary hypothyroidism is caused by the following conditions (Kostoglou-Athanassiou & Ntalles, 2010):
- Dysgenesis/thyroid agenesis
- External radiotherapy
- Radioactive iodine therapy
- Iodine excess or deficiency
- Chronic autoimmune thyroiditis
Central/secondary hypothyroidism is caused by the following pituitary conditions:
- Personal history of pituitary apoplexy
- Personal history of head trauma
- Personal history of radiotherapy or pituitary surgery
- Pituitary adenomas
The following hypothalamus complications also lead to the development of central/secondary hypothyroidism:
- Personal history of radiotherapy or hypothalamic surgery
- Personal history of suprasellar tumors
The general or most commonly reported causes of hypothyroidism include the following (Patil, Rehman, & Jialal, 2020):
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- Worldwide iodine deficiency
- Autoimmune thyroid diseases
- Hashimoto’s thyroiditis
- Iodine fortification
- Iodine deficient geographical locations
- Drugs including lithium, interleukin-2, phenobarbital, rifampicin, interferon, stavudine, and amiodarone
- Thyroid surgery
- Head/neck radiotherapy
- Neoplastic disorders of hypothalamus/pituitary
- Infiltrative conditions of hypothalamus/pituitary
- Inflammatory complications of hypothalamus/pituitary
- Iatrogenic disorders of hypothalamus/pituitary
- Genetic conditions of hypothalamus/pituitary
- Postpartum complications
Symptoms of Hypothyroidism
The limited production of thyroid hormone inside the human body leads to the development of hypothyroidism. The patients affected with hypothyroidism exhibit a limited level of thyroid hormone in their blood. The deteriorated function of the butterfly-shaped thyroid gland (at the neck’s lower front) potentially reduces the serum level of the thyroid hormone.
Eventually, the reduced concentration of thyroid hormone reaches the body tissues, thereby impacting their energy level. The thyroid hormone assists body physiology by elevating/optimizing the energy level of body organs, including muscles, the heart, and the brain. The sustained deficit of thyroid hormone inside the human body potentially slows down the entirety of bodily processes. This eventually increases the risk of the following symptoms (Mayo Clinic, 2020):
- Dry skin
- Cold feeling
- Weight gain
- Memory impairment
- Reduced heart rate
- Thinning of hair
- Irregular or heavy menses
- Muscle pain/stiffness/tenderness
- Swelling/stiffness/pain in joints
- Increase in blood cholesterol level
- Puffy face
The atypical symptoms of hypothyroidism substantiate the requirement of the TSH blood test for its diagnosis. Hypothyroidism inherits between generations. Accordingly, individuals with a family history of hypothyroidism experience an elevated risk of developing the disease. The annual testing of TSH is necessarily required to evaluate/rule out the development of hypothyroidism in predisposed individuals.
What Are the Risk Factors of Hypothyroidism?
Some of the significant risk factors of hypothyroidism include the following:
- Pregnancy or postpartum complications
- History of partial thyroidectomy
- Radiation therapy to upper chest and neck
- Anti-thyroid therapy
- Autoimmune diseases, including celiac disease and type-1 diabetes mellitus
- Family history of thyroid complications
- Age greater than 60 years
- Female gender
How Is Hypothyroidism Tracked or Diagnosed?
No well-defined characteristic symptoms/clinical manifestations of hypothyroidism have been reported so far in the medical literature (American Thyroid Association, 2020). Sometimes, hypothyroidism symptoms remain undiagnosed or unexplored due to other co-morbidities and their clinical manifestations. The physicians, therefore, require careful observation of the clinical history and symptoms of the patients suspected of hypothyroidism. They require observing the following points while recording the personal/family history of the suspected patients:
- The family history of thyroid disease
- Medication history based on thalidomide, interleukin-2, interferon-alpha, lithium, and amiodarone
- Personal history of radiation therapy for neck cancer
- Personal history of thyroid surgery
- Health-related changes leading to a reported slow-down in the body’s physiological processes
The physical assessment should effectively evaluate/rule out the following attributes:
- Reduction in heart rate
- Decreased reflexes
- Swelling over the thyroid gland
- Dry skin
The following lab tests help in diagnosing hypothyroidism in the suspected patients:
- TSH level indicates the body’s overall T4 (thyroid hormone) demand. The elevated TSH level in blood reveals the body’s increased requirement for producing T4. Accordingly, the TSH test helps in tracking T4 level elevation in the context of diagnosing hypothyroidism.
- Thyroxine binding globulin attaches a major portion of T4 while disallowing its transport into the body tissues. The unattached T4 (constituting 1–2 percent of the entire T4) enters into the body tissues to support their normal physiology. The tests including free T4 index and free T4 help in evaluating the serum concentration of unaffixed T4 in the human body.
Are There Any Complications?
Hypothyroidism, if left untreated, results in the development of the following complications:
- Birth defects
- Peripheral neuropathy
- Mental health complications
- Cardiac problems
How Is It Treated?
Hypothyroidism cannot be cured; however, regular maintenance of T4 and TSH levels is possible through dietary interventions, exercise, and medication. The functional disruption of the thyroid appears reversible in individuals affected with viral thyroiditis. Pregnancy-induced hypothyroidism also reverses with time.
T4 replacement therapy is an approved intervention for normalizing the level of thyroid hormone in hypothyroid patients. The administration of synthetic thyroxine pills helps to overcome free T4 deficiency in hypothyroid patients. However, synthetic thyroxine is not recommended for patients affected by life-threatening hypothyroidism or severe myxedema.
Some hypothyroid patients who do not benefit from thyroxine alone require the co-administration of Cytomel® (T3) to enhance their therapeutic outcomes. Hypothyroid patients require modifying their thyroxine dosage based on their clinical manifestations under medical supervision.
What Are the Risks Associated With Synthetic Thyroxine?
The excessive administration of synthetic thyroxine increases the risk of the following symptoms (American Thyroid Association, 2020):
- Skipping/racing heart
- Shortness of breath
- Muscle weakness
- Exercising difficulty
- Feel of hotness and shakiness
- Appetite elevation
- Sleeping difficulty
Is It Possible to Prevent or Control Hypothyroidism?
The primary prevention of hypothyroidism is based on reducing the risk factors among healthy individuals. The secondary prevention of hypothyroidism is based on occult disease screening (Cooper & Ridgway, 2002). However, tertiary prevention is based on reducing the risk of thyroid hormone overdose and iatrogenic disease. The optimal medical care for hypothyroid patients is highly needed to effectively reduce the risks of severity enhancement of their disease condition (Azizi et al., 2018). Some of the significant measures for reducing the risk of autoimmune hypothyroidism are mentioned below (Laurberg et al., 2013).
- Smoking cessation
- Optimization of dietary iodine
- Alcohol intake moderation
The regular assessment of TSH and FT4 is highly required during levothyroxine therapy to check the disease intensity. Some hypothyroid patients experience a persistently elevated TSH level based on the following factors (Chakera et al., 2012):
- Thyroid hormone resistance
- The activity of heterophil antibodies and their impact on laboratory assay
- Autoimmune gastritis/celiac disease
- Consumption of levothyroxine with diet
- Concomitant drug interactions
- Reduced medication compliance
- Inappropriate dosage of levothyroxine
Hypothyroid patients require controlling the above-mentioned factors to reduce the risk of their TSH elevation. Some of the commonly practiced hypothyroidism management measures include the following (Medical News Today, 2020).
- Utilization of iodine supplements
- Consumption of prenatal vitamins and iodized salt during pregnancy
- Administration of vitamin D
- Administration of probiotics
Can Hypothyroidism Be Treated With Herbs?
The below-mentioned herbs prove advantageous in treating the clinical manifestations of hypothyroidism or sub-clinical hypothyroidism in research settings (Metro, et al., 2018, Sinadinos & Herbalist, n.d.). However, you should consult with your primary healthcare provider before starting any treatments.
- Aloe barbadensis miller juice
- Female hormone optimizing herbs
- Immune system modulating herbs
- Lymphatic herbs
- Circulatory system stimulating herbs
- Adrenal herbal tonics
- Adaptogen herbs
- Iodine rich seaweeds
- Withania somnifera
- Centella asiatica
- Eleutherococcus senticosis
- Panax quinquefolium
- Panax ginseng
- Glycyrrhiza glabra
- Glycyrrhiza uralensis
- Aralia californica
- Oplopanax horridum
- Codenopsis pilosula
- Ganoderma sinensis
- Schisandra chinensis
- Rehmannia glutinosa
- Silybum marianum
- Curcuma longa
- Rumex crispus
- Zanthoxylum americanum
- Zingiber officinale
- Ginkgo biloba
- Crataegus oxycantha
- Asclepias Asperula
- Ceanothus americanus
- Galium aparine
- Phytolacca Americana
- Phytolacca decandra
- Vitex agnus-castus
- Cimicifuga racemose
- Angelica sinensis
- Brassica nigra
- Sinapis alba
American Thyroid Association. (2020). Hypothyroidism. Retrieved from https://www.thyroid.org/hypothyroidism/
Azizi, F., Mehran, L., Hosseinpanah , F., Delshad, H., & Amouzegar, A. (2018). Secondary and Tertiary Preventions of Thyroid Disease. Endocrine Research, 124-140. doi:10.1080/07435800.2018.1424720
Chakera, A. J., Pearce , S. H., & Vaida, B. (2012). Treatment for primary hypothyroidism: current approaches and future possibilities. Drug Design, Development, and Therapy, 1-11. doi:10.2147/DDDT.S12894
Cooper, D. S., & Ridgway, E. C. (2002). Thoughts on Prevention of Thyroid Disease in the United States. Thyroid, 925-929. doi:10.1089/105072502761016566
Kostoglou-Athanassiou, I., & Ntalles, K. (2010). Hypothyroidism - new aspects of an old disease. Hippokratia, 14(2), 82-87. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2895281/
Laurberg, P., Andersen, S., Pedersen, I. B., Knudsen, N., & Carlé, A. (2013). Prevention of Autoimmune Hypothyroidism by Modifying Iodine Intake and the Use of Tobacco and Alcohol Is Manoeuvring Between Scylla and Charybdis. Hormones, 30-38. doi:10.1007/BF03401284
Mayo Clinic. (2020). Hypothyroidism (underactive thyroid). Retrieved from https://www.mayoclinic.org/diseases-conditions/hypothyroidism/symptoms-causes/syc-20350284
Medical News Today. (2020). What is hypothyroidism? Retrieved from https://www.medicalnewstoday.com/articles/163729
Metro , D., Cernaro, V., Papa, M., & Benvengac, S. (2018). Marked improvement of thyroid function and autoimmunity by Aloe barbadensis miller juice in patients with subclinical hypothyroidism. Journal of Clinical and Translational Endocrinology, 18-25. doi:10.1016/j.jcte.2018.01.003
Patil, N., Rehman, A., & Jialal, I. (2020). Hypothyroidism. In StatPearls. Treasure Island (Florida): StatPearls Publishing. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK519536/
Sinadinos, C., & Herbalist, C. (n.d.). Herbal Therapeutic Treatments for Hypothyroidism. Retrieved from https://www.americanherbalistsguild.com/sites/default/files/sinadinos_christa_-_herbal_support_for_hypothyroidism.pdf
This content is for informational purposes only and does not substitute for formal and individualized diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed medical professional. Do not stop or alter your current course of treatment. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.
© 2020 Dr Khalid Rahman
Dr Khalid Rahman (author) from India on March 03, 2020:
My pleasure :-)
Thanks for your valuable feedback.
Audrey Hunt from Pahrump NV on March 02, 2020:
I take levothyroxine for my thyroid problem. Thanks for this informative and helpful article.
remedylist on February 29, 2020:
Dr Khalid Rahman (author) from India on February 28, 2020:
Thanks a lot :-)
Sarahkhalid on February 28, 2020:
Interesting, excellent and very helpful. It was a great article. I came to know everything whatever article you wrote.