Secretes three hormones essential for proper regulation of metabolism◦ Thyroxine (T4)

◦ Triiodothyronine (T3)

◦ 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

FatigueFatigue PalpitationsPalpitations NervousnessNervousness Heat intoleranceHeat intolerance Irritability Irritability

levothyroxine (Synthroid, Levothyroidl)◦ Synthetic thyroid hormone T4

liothyronine (Cytomel)◦ Synthetic thyroid hormone T3

liotrix (Thyrolar)◦ Synthetic thyroid hormone T3-T4 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 (I131) 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