Introduction
The thyroid gland is an endocrine gland located in the midline of the anterior neck. It is responsible for the production of thyroid hormones (T3, T4) and calcitonin and helps in the regulation of growth, metabolism, and serum concentrations of electrolytes. Any alterations in the production of thyroid hormones due to diseases affecting the thyroid gland can result in conditions such as thyroiditis, hypothyroidism, hyperthyroidism, etc.
What Is Hypothyroidism?
Decreased production of thyroid hormone is called hypothyroidism. It is also called underactive thyroid disease. It is a common condition and may not cause severe symptoms in the early stages, but over age, if left untreated, it can lead to problems such as high cholesterol, heart problems, etc.
Hypothyroidism is more commonly seen in females than males and can affect people of all ages. However, the incidence increases with advancing age and is particularly seen in elderly women, usually after menopause. According to recent community surveys, the prevalence of hypothyroidism is found in community-dwelling and hospitalized elderly people. Studies evaluating geriatric patients demonstrated that 15 % of women and 17 % of men with previously undiagnosed hypothyroidism.
What Are the Causes of Hypothyroidism in Elderly People?
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Autoimmune Thyroiditis: It is the most common cause of hypothyroidism in elderly people compared to younger adults. It progresses slowly with age, and the symptoms vary among people. The immune system generates antibodies that attack the thyroid cells, resulting in decreased production of thyroid hormones. It can be due to genetic or environmental factors or radiation exposure.
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Post-Surgical Hypothyroidism: It is secondary to partial or total thyroidectomy (surgical removal of the thyroid gland) and is mostly seen in elderly women.
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Subclinical Hypothyroidism: A family history of thyroid disease, radioactive iodine therapy, or an injury to the thyroid can cause subclinical hypothyroidism, wherein the thyroid-stimulating hormone (TSH) levels are slightly elevated, but the levels of T3 and T4 are normal. It usually resolves on its own, but some cases can progress to overt hypothyroidism.
What Are the Signs and Symptoms of Hypothyroidism?
Signs and symptoms of hypothyroidism in elderly people are similar to the symptoms of the normal aging process; these include:
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Fatigue.
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Intolerance to cold.
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Weight gain.
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Increased sleepiness.
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Muscle aches, cramps, and weakness.
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Joint pain and stiffness.
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Swelling of the thyroid gland.
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Problems with memory and concentration.
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Puffy face and drooping eyelids.
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Neurological symptoms include depression, impaired hearing, hypogeusia (reduced taste sensation), and dysgeusia (altered taste sensation).
What Are the Risk Factors of Hypothyroidism?
Risk factors of hypothyroidism include:
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Elderly adults above 60 years of age.
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People with familial history of thyroid diseases.
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Patients under radiation therapy in the neck or upper chest area.
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Surgeries of the thyroid gland, such as partial thyroidectomy.
How Can Hypothyroidism Be Managed in Older People?
The symptoms of hypothyroidism vary among individuals, based on the severity of the condition and the age of the patient.
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The treatment of hypothyroidism in older people is initiated with the administration of low doses of Sodium Levothyroxine. The dose is lower compared to doses administered in young adults, which is approximately 0.25 to 0.5 mcg/kg/day (micrograms per kilogram per day). After the assessment of the starting dose, it gradually increased by 12.5 mcg to 25 mcg every four to six weeks.
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Levothyroxine must be taken preferably without food or at least 30 minutes before breakfast to avoid interaction of the medicine which may affect the absorption. Recent clinical trials showed that older patients without cardiovascular diseases could be safely started on full replacement doses of thyroxine of around 1.6 mcg per kg without any side effects.
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Randomized trials have demonstrated that normalizing the physiologic secretion of thyroid hormone by adding doses of Liothyronine (T3) to thyroxine did not show any significant changes in the mood, cognitive function, or quality of life of patients. The measurement of TSH levels must be monitored after a change in thyroxine dosage each time. Treatment with Thyroxine is known to increase cognitive performance in elderly people.
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Supplementation of thyroid hormones may correct the deficiency. However, patients suffering from conditions such as ischemic heart disease, etc., may not tolerate full replacement doses. Hence, the thyroxine doses must be determined by the presence of comorbidities, other medications, and the severity or progression of the disease. The recommended dose in the geriatric population for patients with primary hypothyroidism is 20 mcg lower, and the maintenance dose is 40 mcg lower than the adult dose.
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In elderly patients with cognitive or functional impairment, alternative dosing schedules may be advised. Various medicines taken by older adults due to comorbid conditions may interfere with thyroxine absorption and metabolism, such as calcium carbonate, ferrous sulfate, Colestipol, Raloxifene, Estrogen replacement therapy, Carbamazepine, Phenobarbital, etc.; hence the treatment must be started with the lowest possible dose, depending on the condition of the patient.
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Conservative treatment options in managing hypothyroidism include; regular exercises or physical activities that may help improve the metabolism and maintain weight. Fatigue in elderly people can result in loss of muscle mass, muscle pain, and cramps; physical exercises and yoga can be started gradually, which help treat these conditions and also helps improve muscle strength and posture.
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Treatment of subclinical hypothyroidism aims to relieve the symptoms, avoid the disease progression and also prevent cardiovascular complications.
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Treatment of overt hypothyroidism is by oral replacement with synthetic L-thyroxine. It is converted into FT3, an active form of thyroid hormone, and is administered at a single dose, less than the adult dose of 1.6 micrograms per kg.
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Overtreatment of thyroxine in older people may be associated with heat intolerance, irritability, palpitations, anxiety, weight loss, etc.; hence the treatment and the thyroid levels must be frequently monitored.
Conclusion
The management of hypothyroidism in older adults can be more challenging compared to young patients. Supplementation of thyroid hormones by Levothyroxine initially at lower doses with a gradual increase can help manage hypothyroidism in elderly people. Frequent monitoring of thyroid levels and drug dosage and regular physical exercises help prevent disease progression.
