Academic journal article International Journal of Child Health and Human Development

Adolescence and Disorders of Endocrinology

Academic journal article International Journal of Child Health and Human Development

Adolescence and Disorders of Endocrinology

Article excerpt

Introduction

Growth and development are very important aspects of consideration in adolescents. Hormone disturbances in any of the endocrine hormone axis can lead to significant disturbances in growth and pubertal development. Therefore, accurate monitoring of growth, maintaining a high index of suspicion for underlying hormone disorders, and timely intervention, are all important to minimize these abnormalities and assure healthy adolescents. The following discussion focuses on a few of the endocrine concerns important in adolescents (1-7).

Thyroid hormone disorders

Hypothyroidism (8-12)

Hypothyroidism results from decreased secretion or insufficient availability of thyroid hormone to the body. Hypothyroidism seen in adolescence may be acquired or congenital. Congenital hypothyroidism is present since birth and may be due to thyroid dysgenesis or dyshormonogenesis, and requires lifelong thyroid hormone replacement. Acquired hypothyroidism may be due to autoimmune thyroid disorders or due to interference with thyroid hormone synthesis by foods, drugs, medications. Autoimmune hypothyroidism is referred to as Hashimoto's lymphocytic thyroiditis and as the name implies is characterized by lymphocytic infiltration and has a genetic predisposition. Iodine deficiency and radiation exposure to the head and neck may also result in hypothyroidism.

The signs and symptoms of hypothyroidism could be very subtle and insidious, and may include growth deficits, dry pale skin, coarse brittle hair, bradycardia, cold intolerance, constipation, and meno/metrorrhagia. Findings may include coarsening of facial features, sallow pale skin, hung up deep tendon reflexes, and bradycardia. The thyroid gland is usually enlarged, firm, nontender, cobblestone like, may be irregular and nodular. Laboratory investigations reveal low levels of thyroid hormone (T4, free T4, T3, and free T3) and high levels of TSH.

Treatment

The treatment for hypothyroidism essentially requires replacement with synthetic formulation of thyroxine. Levothyroxine or T4 is the endogenous hormone secreted by the thyroid gland which is converted to its active metabolite L.-triiodothyronine or T3. The doses are titrated by monitoring of free T4 and TSH levels, with an aim to keep both of these values within normal range. The usual dose in adults and older adolescents for treatment of hypothyroidism is 1.7 mcg/kg/day orally. The pediatric doses vary according to age and comparatively the younger children require a much higher per kilogram dose versus the adolescents (see Table 1).

It is important to be aware of these relative differences in dose in the different age groups. Overall mild or subclinical hypothyroidism generally may require lower doses.

Levothyroxin is available in multiple brand names and the tablets are color-coded, and available in multiple strengths including 25 mcg, 50 mcg, 75 mcg, 88 mcg, 100 mcg, 112 mcg, 125 mcg, 137 mcg, 150 mcg, 175 mcg, 200 mcg and 300 mcg. The medication is generally administered once daily about 30 minutes before breakfast.

However, more practically, the patients are advised to take the dose later in the day if they happen to miss the morning dose. Thyroid function tests including free T4 and TSH should be done in about 4 weeks after initiating thyroid hormone replacement and after any changes in medication dose are made. If there is suspicion of underlying adrenal insufficiency, it should be ruled out prior to starting of thyroid hormone replacement therapy. Thyroid hormone replacement is contraindicated in uncorrected adrenal insufficiency.

Hyperthyroidism

Hyperthyroidism results from excessive secretion of thyroid hormone and the most common cause in adolescents is autoimmune hyperthyroidism also referred to as Graves' disease. It is 5-6 times more common in adolescent girls than boys and generally has a strong genetic predisposition. Clinical features vary greatly, may be nonspecific, and the onset may be often insidious. …

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