 Secretes three hormones essential for proper regulation of metabolism ◦ Thyroxine (T 4 ) ◦ Triiodothyronine (T 3 ) ◦ Calcitonin  Located near the parathyroid gland ◦ Which is responsible for maintaining adequate levels of calcium in the extracellular fluid

 Primary: abnormality in the thyroid gland itself  Secondary: results when the pituitary gland is dysfunctional and does not secrete TSH  Tertiary: results when the hypothalamus gland does not secrete TRH, which stimulates the release of TSH

 Cretinism ◦ Hyposecretion of thyroid hormone during youth ◦ Leads to cretinism: low metabolic rate, retarded growth and sexual development, possibly mental retardation

 Myxedema ◦ Hyposecretion of thyroid hormone during adulthood ◦ Decreased metabolic rate, loss of mental and physical stamina, weight gain, loss of hair, firm edema, yellow dullness of the skin

 Goiter ◦ Enlargement of the thyroid gland ◦ Results from overstimulation by elevated levels of TSH ◦ TSH is elevated because there is little or no thyroid hormone in circulation

 Common symptoms ◦ Thickened skin ◦ Hair loss ◦ Constipation ◦ Lethargy ◦ Anorexia

 Caused by several diseases ◦ Graves’ disease ◦ Plummer’s disease (toxic nodular disease) ◦ Multinodular disease ◦ Thyroid storm (induced by stress or infection)

 Affects multiple body systems, resulting in an overall increase in metabolism ◦ Diarrhea ◦ Flushing ◦ Increased appetite ◦ Muscle weakness ◦ Sleep disorders ◦ Altered menstrual flow  Fatigue  Palpitations  Nervousness  Heat intolerance  Irritability

 levothyroxine (Synthroid, Levothyroidl) ◦ Synthetic thyroid hormone T 4  liothyronine (Cytomel) ◦ Synthetic thyroid hormone T 3  liotrix (Thyrolar) ◦ Synthetic thyroid hormone T 3 -T 4 combined  Thyroid ◦ Desiccated (dried) animal thyroid gland

 Thyroid preparations are given to replace what the thyroid gland cannot produce to achieve normal thyroid levels (euthyroid)  Thyroid drugs work the same way as thyroid hormones

 To treat all three forms of hypothyroidism  Levothyroxine is the preferred drug because its hormonal content is standardized; therefore, its effect is predictable  Thyroid replacement in patients whose thyroid glands have been surgically removed  Thyroid replacement when thyroid is destroyed by radioactive iodine in the treatment of thyroid cancer or hyperthyroidism

 Cardiac dysrhythmias are the most significant adverse effect  May also cause: ◦ Tachycardia, palpitations, angina, hypertension, insomnia, tremors, headache, anxiety, nausea, diarrhea, menstrual irregularities, weight loss, appetite changes, sweating, heat intolerance, others

 Radioactive iodine (I 131 ) works by destroying the thyroid gland  Surgery to remove all or part of the thyroid gland ◦ Lifelong thyroid hormone replacement will be needed

 Antithyroid drugs: thioamide derivatives ◦ methimazole (Tapazole) ◦ propylthiouracil (PTU)

 Used to palliate hyperthyroidism and to prevent the surge in thyroid hormones that occurs after the surgical treatment or during radioactive iodine treatment for hyperthyroidism  May cause liver and bone marrow toxicity

 Assess for drug allergies, contraindications, potential drug interactions  Obtain baseline vital signs, weight  Cautious use advised for those with cardiac disease, hypertension, and pregnant women

 During pregnancy, treatment for hypothyroidism should continue  Fetal growth may be retarded if maternal hypothyroidism is untreated during pregnancy ◦ Adjust dosage every 4 weeks to keep TSH at the lower end of the normal range

 Teach patient to take thyroid drugs once daily in the morning to decrease the likelihood of insomnia if taken later in the day  Teach patient to take the medications at the same time every day and not to switch brands without physician approval

 Teach patients to report any unusual symptoms, chest pain, or heart palpitations  Teach patients not to take OTC medications without physician approval  Teach patients that therapeutic effects may take several months to occur

 Antithyroid medications ◦ Better tolerated when given with food ◦ Give at the same time each day to maintain consistent blood levels ◦ Never stop these medications abruptly ◦ Avoid eating foods high in iodine (seafood, soy sauce, tofu, and iodized salt)

 Monitor for therapeutic response  Monitor for adverse effects

 When assessing the older patient, the nurse keeps in mind that certain non-specfiic symptoms may represent hypothyroidism n older patients, such as:  A. Cold intolerance, depression.  B. Leukopenia, anemia.  C. Loss of appetite, polyuria.  D. Weight loss, dry cough.

 When teaching a patient who has a new prescription for thyroid hormone, the nurse should instruct the patient to notify the physician when which adverse effects are noted?  A. Anxiety.  B. Appetite changes  C. Headache.  D. Palpitations