⮚ GENERAL OVERVIEW OF HYPOTHYROIDISM
Hypothyroidism is referred to as disruption or complications of the thyroid gland to secrete adequate amounts of hormone to fulfill the metabolic demands of the body. These ailments if untreated borne plethora of other problems too such as high blood pressure, high level of triglycerides, infertility, muscle disorders and intellectual disability. In the list of endocrine disorders, hypothyroidism percentage is proliferating tremendously. The ratio of Females is more affected than males with this disorder to suffer it. Most women over 40 years old are affected by the idiopathic type of thyroidism.
⮚ EPIDEMIOLOGY
An investigation of a huge health plan portray that database found an estimate of 77 000 cases, which are more affected with this disease in the United States. To collect the second estimate of prevalence, surgical incidence data was entered into an epidemiological model. Using the surgical-based incidence technique, an estimate of 117, 342 significant neck operations was obtained. Hypothyroidism occurred in around 7.6% of surgical patients, 75% of these situations were for a short span while 25% were chronic. The proportion of adults suffering with this is 7.5%, males having 6.0% prevalence and women having 17.5% which reflect that men are four times more prone towards Hypothyroidism.
⮚ ETIOLOGY
Multifarious environmental and genetic variables are involved in the development of chronic autoimmune thyroiditis but the ratio of genetic variables is always low such as CTLA-4 and the HLA complexes indulge primarily. Environmental contribution, iodine consumptions and infections are the most imperative factors which instills underactive thyroidism. One study depicts that plenty of infections are strongly towards the disease. For example, antibodies like EBV were available in higher levels in the children with this disorder. It has also been found that radiation treatment substantially harms the thyroid and results in symptomatic hypothyroidism that occurs comparatively at a slower pace after exposure to radiation. Last but not the least cause of this disorder is the tyrosine kinase inhibitor such as lithium, sunitinib, interferon alpha and amiodarone, are the pharmaceuticals that induce hypothyroidism.
⮚ SYMPTOMS
Hypothyroidism can be differentiated as subclinical (moderate) or clinical (severe) based on its symptoms. Determining the disease's severity is so significant because minor instances may not show any symptoms, while critical cases may result in a coma. People with this terrible condition face a variety of typical symptoms like tiredness, feeling cold, obese, bowel problem, sadness, slow understanding, muscle pain/cramps, weakness, dry skin, breakable hair as well as nails, and menstrual pain. Without consultation of medical practitioners a huge number of people would inevitably continue to experience these nonspecific symptoms, merely because of ignorance. The intensity of thyroid-related symptoms in a person with subclinical hypothyroidism may prove to be less severe as compared to the person with overt clinical one.
⮚ PATHOPHYSIOLOGY
The most common cause of hypothyroidism is the inadequacy of thyroid gland to secrete required thyroid hormone whereas in few cases thyroid disability can also be caused due to the complications in pituitary and hypothalamic glands. Brain secreted hormone Thyrotropin-releasing hormone (TRH), induces the pituitary gland to release thyroid-stimulating hormone (TSH). As this gland is regulated by TSH to generate and release mostly T4 (about 100–125 nmol per day) and comparatively lesser amounts of T3. T4 has a half-life of seven to ten days. Ultimately, 5'-deiodination converts T4 to T3 superficially. T4 and T3 levels both have a negative feedback loop which influences the synthesis of TRH and TSH. Hypothyroidism probably entitles the alteration into the anatomy or physiology of any of these organs or pathways. When T4 synthesis is mitigated, the pituitary gland produces more TSH which causes the thyroid parenchyma to enlarge and become more parenchymatous so that the production of T3 elevates more. Reduction in the amount of thyroid hormone results in the heightening of TSH secretion. In non-equilibrium a period, which takes place at the initiation of hypothyroidism, there can be considerable variation between the levels of TSH and the plasma thyroid hormone concentrations therefore the control system reacts quite slowly to these changes.
⮚ DIAGNOSIS
A serum TSH level should be obtained by the doctor if symptoms and indications increase the level of suspicion. Physicians analyzed the signs and symptoms that depict that testing should be performed to evaluate whether the level of TSH is within the normal reference range or not. To check the presence of pituitary gland FT4 level is taken and if found that FT4 level is under normal condition, further pituitary or thyroid testing is not necessary. The condition of Hyperthyroidism usually occurs when the level of TSH found to be low such as less than 0.4 mIU per L whereas the test of Serum 18 FT4 levels measured if the level of TSH is high like more than 4.5 mIU per L. If the amount of TPO antibody increased in test result, the low level of FT4 reflects clinical hypothyroidism also known as autoimmune hypothyroidism (Hashimoto thyroiditis. The main observation of primary hypothyroidism is a proliferation of TSH level. Although the free T4 concentration goes below normal as the illness develops, the majority of people have free T4 levels of balanced hypothyroidism that are within normal range. Despite the low level of T4, the T3 content is frequently kept within the usual range. When the level of TSH is low and T4 level reduced, patients are probably suspected with secondary hypothyroidism, or pituitary failure.
⮚ TREATMENT
For the treatment of clinical hypothyroidism Levothyroxine is an essential drug to normalize the TSH level and alleviate symptoms. The use of T3, as a single or in conjunction with Levothyroxine, is not supported by the researchers yet. In the areas where the availability of iodine is sufficient there is no need to provide or distribute the iodine boon foods such as iodine kelp or other iodine rich foods. Levothyroxine should be taken once in a day, four hours before or after medications that may reduce absorption while thirty to sixty minutes before meals. Adults with hypothyroidism require around 1.7 microg/kg of body weight daily for treatment. In youngsters, higher dosages (up to 4 microg/kg of body weight per day) may prove to be necessary but for older aged people a daily dose of 0.1 microg/ kg is sufficient. People with Hypothyroidism should swallow this dosage until the level of serum TSH shifts to normal. Few populations over the age of 50 who have undergone this therapy or who have been known to have these ailments for a short span like for a few months are immensely benefited from full replacement dosages of Levothyroxine. There is plethora of other drugs available in the markets which curb the absorption rate via hindering the intestine ability to absorb Levothyroxine such Sucralfate, aluminum hydroxide antacids, ferrous sulfate and cholestyramine, Administration of Levothyroxine and these medications should occur at least 4 hours apart. Consequently the high dosage of thyroid hormone may play an integral role due to the substantial role of other drugs, especially the antituberculous drug rifampin and the anticonvulsants carbamazepine and phenytoin, to increase the metabolism rate of Levothyroxine. One T3 synthetic drug Liothyronine has uniform potency but is more expensive as well as has a higher risk of severe cardiac effects that is why it is very challenging to monitor with standard laboratory testing. Another one is Liotrix. It is also synthetic and available in 4:1 (T4:T3) is a costly supplement but is pure, accessible and chemically stable. Whereas other exogenous thyroid hormone raises the risk of fracture and lowers bone density.
Frequently asked Questions
1. What is hypothyroidism?
The term "hypothyroidism" explains the complications or disturbances in the thyroid glands to release enough thyroid hormone to meet the body's metabolic needs. This condition is also known as underactive thyroids.
2. What are thyroid disorders? How do they happen?
Hyperthyroidism and hypothyroidism are the two most prevalent thyroid conditions. The former one is based upon overactive thyroid gland or the overproduction of thyroid hormones, whereas the latter one is solely caused by low thyroid hormone production and an underactive thyroid gland.
3. What are the most significant symptoms of Hypothyroidism?
The most common symptoms are increased weight, disruption in the neck, brain related issues, digestion problems, muscle cramps, blurred vision, menstrual pain and breaking of hairs and nails.
4. Which foods are dangerous in thyroid disorder?
Well there is not any appropriate diet for hyperthyroidism but an individual should monitor how the quantity of cruciferous vegetables, soy and selenium he or she eats. Additionally, one must consume less iodine because thyroid medicine interacts with all of these foods very instantly.
5. Which medication is used for the treatment of this disease?
To address clinical hypothyroidism as well as to restore the level of TSH at normal rate, Levothyroxine is a necessary medication.
6. What is a suitable dose of Levothyroxine for people of different age groups?
For the Treatment of hypothyroidism in adults 1.7 microg/kg of Levothyroxine is required according to weight per day. Higher doses (up to 4 microg/kg of body weight per day) may be compatible for younger individuals, whereas 0.1 microg/ kg per day is adequate in older adults.
7. Enlist the drugs which decrease the absorption of Levothyroxine and why?
The drugs which reduce the absorbing power are aluminum hydroxide antacids, sucralfate, ferrous sulfate and cholestyramine because they all hinder the intestine.
8. Why is Liothyronine not recommendable for the treatment of Hyperthyroidism?
Because it is a very costly synthetic drug as well as it has severe cardiac effects that is why it is not possible to operate at standard laboratory conditions.