Hashimoto’s Thyroiditis
Hashimoto’s thyroiditis is an autoimmune disease that causes hypothyroidism, or underactive thyroid. In this case, the immune system attacks and destroys the thyroid located in the neck which then fails to produce thyroid hormones. The thyroid is a small gland which is butterfly-shaped and located in the front of the neck. The thyroid hormones produced by the gland are used to control how the body uses energy and the way the heartbeats. It means that almost every organ of the body is affected. Without the thyroid hormones, the functions of the body may slow down.
The Hashimoto’s thyroiditis is believed to be the major cause of hypothyroidism in parts of America especially the United States of America resulting in non-endemic goitre. The disease affects around five per cent of the population at some point in their life. About 1 to 2 in a population of 1000 people are believed to have this disorder in a given period. It affects a larger population of women than men. Even though it may occur at any age from children to the aged, it is commonly observed in females aged between 30 to 60 years. The disease is more common in regions of high iodine dietary intake, and among genetically vulnerable people. In fact, in twin studies, it has been found that there is an increase in autoimmune thyroids concordance in monozygotic twins than in dizygotic twins. The research has been backed up by the Danish studies where rates of concordance were found to be about 55 per cent and in dizygotic twins, it was found to be 3 per cent. All the above information supports the perspective that 80% of inclination is as a result of genetic factors allocating 21 per cent for environmental and sex hormone factors.
Hashimoto thyroiditis disorder doesn’t present with any distinctive signs and symptoms. The condition continues gradually over a long period and people with this condition may not have any earlier symptoms. The hypothyroidism of this disorder often is subclinical meaning that it is mild and without symptoms, particularly at its early stages. When hypothyroidism continues, some symptoms start to develop. Such symptoms include the feeling of tiredness, increased weight, problems of tolerating cold, experiencing pain in the joints and muscles, having thin dry hair, feeling depressed, memory issues, slow heart rates, and irregular menstrual periods and issues when conceiving. The lapse of time is affected by the quickness of the beginning and severity of the hypothyroidism’s clinical state. The presentation of a patient with hypothyroidism could be subclinical and may be identified from routine screening of thyroid function.
The thyroid gland is located lower to the thyroid cartilage in the anteroinferior neck. In the normal condition, the thyroid gland has two lobes and consists of lower-middle and upper poles linked by a thin bridge of thyroid tissue (isthmus). The tissue straddles the trachea anteriorly and the lobes extend on the sides of the trachea, surrounded laterally by carotid arteries and internal jugular veins. The pyramid-shaped lobe when present arises from the isthmus and tapers superiorly just in front of the thyroid cartilage and can be seen in 20 to 30 per cent of patients. The thyroid gland has two kinds of cells namely; parafollicular and follicular cells. The follicular cells secrete the main thyroid hormones thyroxine (T4) and tri-iodothyronine (T3). The cells need a sufficient supply of iodine to enable them to produce a sufficient amount of thyroid hormones. The size, shape and volume of the thyroid gland vary with age and sex. Normal thyroid measures 18 to 20milimetres longitudinaly and 9 to 10 millimetres anteroposterior (AP) diameter in newly born babies. In adults, it measures between 40 to 60 mm longitudinally and 13 to 18 millimetres AP. The normal thyroid volume limits are 10 to 15 ml for women and 12 to 18 ml for men. As a result of the variations in volume, the volume of the thyroid is more important in determining gland enlargement. It is observed that the volume is slightly higher in men than in women and can be used in assessing the necessity for surgery.
The cause of Hashimoto thyroiditis is not exactly known, but it is believed that some factors play a key role. For instance, it is believed that this condition is reflected in genes that it can be inherited. It is also believed that sex hormones are involved since it is observed that women are more affected by the condition than men. Research also suggests that excess iodine may trigger thyroid disorder in susceptible individuals. Finally, exposure to radiations increases the chances of getting this disorder. When the disorder continues developing, the thyroid starts growing larger and larger and may cause the front of the neck to swell. The swollen thyroid, commonly known as goitre, may cause impingement on the gut or trachea which is usually not painful but impairs swallowing and breathing. After a long period, the thyroid gets damaged and the swelling starts shrinking and finally disappears. When the Hashimoto thyroiditis is not treated, the prolonged hypothyroidism may cause cardiac complications such as frequent heart failure. In its severe stage, hypothyroidism may result in myxedema coma which is a life-threatening condition.
The Hashimoto thyroiditis has no cure, but the levels of the hormone can be regulated by replacing the hormones with medication and can also help restore the normal body metabolism. Thyroid hormone medication can replace the thyroid hormones made before inflammation. Replacing one or all the two thyroid hormones can relieve the symptoms caused by the total or relative lack of hormones due to the Hashimoto thyroiditis condition. The treatment choice for the thyroiditis condition is typically synthetic T4 or thyroxine. Such medication is supposed to be taken indefinitely. Successful treatment relieves the symptoms and signs of hypothyroidism. Failure to take this medication would mean that the level of hormones is not maintained to the normal level. The prognosis for an individual with the condition is excellent with proper treatment. When the thyroid hormone levels are restored through medication, the signs and symptoms of hypothyroidism are reversed. If an individual fails to take medication, the hypothyroidism worsens for long period, potentially resulting in organ damage and severe ill health.
References
Caturegli P, De Remigis A, Rose NR. Hashimoto thyroiditis: clinical and diagnostic criteria. Autoimmunity reviews. 2014 Apr 1;13(4-5):391-7. Retrieved from: https://www.sciencedirect.com/science/article/pii/S1568997214000196
Ragusa F, Fallahi P, Elia G, Gonnella D, Paparo SR, Giusti C, Churilov LP, Ferrari SM, Antonelli A. Hashimotos’ Thyroiditis: epidemiology, pathogenesis, clinic and therapy. Best Practice & Research Clinical Endocrinology & Metabolism. 2019 Nov 26:101367. Retrieved from: https://www.sciencedirect.com/science/article/pii/S1521690X19301186