Thyroid Hormones T3 and T4 Functions

Roles: • Metabolic rate and heat production • Oxygen consumption • Fat, carbohydrate & lipid metabolism • Growth and development • Brain function • Stimulated by TSH from the anterior pituitary gland • Thyroid must have iodine to produce these hormones

Calcitonin...........................................nhibits resorption of calcium & phosphate • Lowers serum calcium levels by retaining calcium/phosphate in the bones • Stimulated with hypercalcemia

Enlarged thyroid gland  Entire gland or multiple nodules  Can be associated with hyperthyroidism, hypothyroidism, or euthyroid state  Causes:  Lack of iodine in the diet  Overproduction or underproduction of thyroid hormones  Nodules in gland  Medications containing thyroid-inhibiting substances

Enlarged thyroid  Dysphagia  Difficulty breathing- can compromise airway!  Goiters can develop into cancer  Nursing Concerns:  ABCs  Stridor is an emergency!  Assess swallowing

reatment:  Goals of treatment are to protect the airway and stop enlargement of the goiter  Medications: dependent on etiology of goiter  Thyroidectomy

n the early morning on an empty stomach (at least 30-60 minutes before food is consumed); food reduces the absorption of this medication Extra Info • Drug of choice for those who require thyroid hormone replacement • Treat s/s caused by hypothyroidism • Started at a low dose and gradually increased to prevent causing hyperthyroidism • Monitor for S/S of hyperthyroidism when beginning therapy or increasing dose • When administered in the appropriate dosage, levothyroxine rarely causes adverse effects • Educate patient to monitor for s/s of hyperthyroidism • S/S include: Tachycardia, angina/chest pain, palpitations, tremors, nervousness, hyperthermia, heat intolerance, and sweating • If these s/s occur, notify the physician right awa

Deficiency of thyroid hormone causing a general slowing of metabolic rate  Classified as primary or secondary  Iodine deficiency is most common cause worldwide  Other causes:  Hashimoto’s thyroiditis  Thyroidectomy  Congenital  Discontinuance of thyroid hormone therapy

ssue is with the thyroid gland itself • Unable to produce thyroid hormones T3 and T4 Low • No issue with Anterior Pituitary Gland • Anterior Pituitary Gland is continuously releasing Thyroid Stimulating Hormone, attempting to stimulate the thyroid to release T3 & T4 High TSH

Issue is with the Anterior Pituitary Gland • Unable to produce Thyroid Stimulating Hormone(TSH)  TSH Low • No issue with Thyroid Gland • TSH is not being released, so the thyroid gland isn’t being stimulated to release its hormones  T3 & T4 Low

Bradycardia  Weight gain  Fatigue & Lethargy  Intolerant to cold  Personality and mental changes  Shortness of breath on exertion  Atherosclerosis  Constipation  Dry skin and hair  Heart failure  Decreased cardiac output  Can progress to myxedema

Hormone replacement therapy with Levothyroxine (Synthroid)  Education  Lifelong medication  Do not abruptly stop and avoid discontinuation  S/S of hyperthyroidism after HRT  Diabetic patients should check BG regularly

Autoimmune disease  Antibodies attack healthy thyroid tissue  Leads to inflammation  Thyroid cells are destroyed  hypothyroidism  Women affected more than men  Can cause goiter  Signs and symptoms similar to hypothyroidism  Diagnostic tests:  Autoimmune antibody testing  TSH, T3, T4 levels  Thyroid scan  Therapeutic measures:  Thyroid hormone therapy

Hypoventilation (can lead to respiratory acidosis)  Hypothermia (less than 95°F)  Hypotension  Bradycardia  Hypoglycemia  Change in LOC  Lethargy

Metabolic rate drops so low that it becomes life threatening  Usually occurs in long-standing undiagnosed hypothyroidism  Precipitated by infection, drugs (opioids, barbiturates), exposure to cold, trauma  Mental sluggishness, drowsiness and lethargy have progressed to coma state  T3/T4 low, TSH high or low

ntubation and mechanical ventilation  Maintain patent airway!  Respiratory support and frequent assessment  Cardiac Monitoring  IV fluids  All medications administered intravenously  IV Levothyroxine  Warm patient with blankets or BAIR hugger  When patients have recovered and are being discharged:  Provide short, written reminders for care information

ncrease in synthesis and release of thyroid hormones  Excess circulating T3 and T4  Most commonly caused by Grave’s Disease  antibodies cause thyroid to overproduce hormones

ssue is with the thyroid gland itself • Over production of the thyroid hormones • T3 and T4 High • Anterior Pituitary Gland is not releasing Thyroid Stimulating Hormone, attempting to stop the thyroid from releasing T3 & T4 • TSH Low

Issue with the Anterior Pituitary Gland • Over production of Thyroid Stimulating Hormone (TSH) • TSH High • No issue with Thyroid Gland • TSH is being over produced, which is over stimulating the thyroid gland & the thyroid is continuously producing and releasing T3 & T4 • T3 & T4 High

Pathophysiology  Increased Metabolic Rate  Increased Beta-Adrengergic Receptor Sites in body  Enhances activity of epinephrine & norepinephrine  Etiology  Graves Disease  Autoimmune disease  Characterized by thyroid enlargement and excessive thyroid hormone secretion  Thyroid nodules  Multinodular goiter  Thyroiditis  Thyroid tumor  Pituitary tumor

Signs and Symptoms  Hypermetabolic State  Everything is sped up!  Heat Intolerance  Internal temperatures are elevated, warm skin  Tachycardia, Palpitations, Hypertension, Chest Pain  Due to increased epinephrine/norepinephrine activity  Risk for angina and dysrhythmias  Increased Appetite, Weight Loss, Frequent Stools  Fatigued & Irritable  Nervousness, Tremors  Goiter  Exophthalmos (occurs only with Graves’ disease)  Tissues behind eyes swell

Goiter  Assess airway and ability to swallow  Cardiac Complications (HTN, Tachycardia, Palpitations)  Administer beta blockers as ordered  Irritability & Restlessness  Provide quiet environment  Exophthalmos  Relieve dry eyes & discomfort (eye drops)  Weight Loss  Increase carbs, proteins, fats, overall calorie intake

Many treatments to attempt to slow the thyroid down  Antithyroid Medications  Methimazole or PTU  Radioactive iodine therapy (RAI)  Thyroidectomy- removal of all or part of the thyroid  Chosen when patient is unresponsive to other tx., has a goiter causing tracheal compression, thyroid cancer  Will cause hypothyroidism, must be placed on Synthroid for life

Destroys thyroid tissue – symptoms of hypothyroidism may occur as RAI therapy takes effect  Nursing care (in hospital):  Limit time spent with patient.  Glove and gown.  Avoid if pregnant.  Take precautions with urine, emesis, body fluids.  Double flush toile

First line treatment for hyperthyroidism • Inhibits thyroid hormone synthesis......................Although methimazole inhibits thyroid hormone synthesis, it does not destroy existing stores of thyroid hormone • It can take 3 to 12 weeks to produce a euthyroid state • If doses administered are too high, it can put the patient into a hypothyroid state • Educate the patient on s/s of hypothyroidism, report to the provider if s/s present • If hypothyroidism occurs, dose should be decreased • Other medications may need to be administered to treat s/s while methimazole is being given to reach a euthyroid state

second line treatment for hyperthyroidism • Inhibits thyroid hormone synthesis...............................lthough PTU inhibits thyroid hormone synthesis, it does not destroy existing stores of thyroid hormone • It can take 3 to 12 weeks to produce a euthyroid state • If doses administered are too high, it can put the patient into a hypothyroid state • Educate the patient on s/s of hypothyroidism, report to the provider if s/s present • If hypothyroidism occurs, dose should be decreased • Other medications may need to be administered to treat s/s while PTU is being given to reach a euthyroid state

Thyrotoxic crisis/thyroid storm----------------------Acute, rare condition in which hyperthyroid manifestations are HEIGHTENED  Life-threatening emergency  Can be caused by stressors in a patient with preexisting hyperthyroidism or after thyroid surgery

Symptoms:  Tachycardia (>150-160 bpm)  Extreme HTN  Hyperthermia  Seizures  N/V/D  Brief attention span, apprehension and restlessness  Delirium  Shock  Heart failure  Coma

Beta Blockers  Antipyretics/cooling blanket  Fluid Replacement  Elevate HOB  Administer O2  Reduce circulating thyroid hormones  Antithyroid drugs: PTU and Methimazole (block synthesis)  Radioactive iodine (inhibits release of hormones into circulation)  Results are not immediate – may take months to reach maximum effec

Total or subtotal thyroidectomy Monitor breathing and swallowing Assess nutrition status Monitor vital signs Administer iodine or antithyroid drugs to achieve euthyroid state

Neck swelling/airway complications Stridor – emergency! Tracheostomy equipment at bedside Monitor vitals! Worried for thyroid storm 18 hours post-op 101 greater risk for seizures BP increasing 180/100 stroke HR over 150 Restlessness increased confusion Stridor on excalation Hypothyroidism complications Monitor drain Semi-fowler position Suction equipment at bedside

Increased secretion of PTH  Increased serum calcium  Etiology:  Hyperplasia  Benign tumor of parathyroid glands  Hereditary  Secondary:  Kidney disease

Diagnostic tests  Serum calcium elevated  24-hour urine for calcium  Phosphate decreased  PTH elevated  X-rays for bone density

Clinical Manifestations:  Can be asymptomatic, or...  Osteoporosis  fractures  Kidney Stones (hypercalciuria)  Muscle weakness, lethargy  Loss of appetite, N/V, constipation  Peptic ulcers  Coma  Cardiac arrhythmias  Cardiac arrest  Patients at risk for injury!

Most effective treatment? Remove it!  Parathyroidectomy  Nonsurgical therapy  For asymptomatic patients  Weight-bearing exercise, high fluid intake, moderate calcium intake  Drugs to lower calcium levels -do not correct underlying problem

Similar to that of thyroidectomy: Monitor for hemorrhage, fluid/electrolyte imbalance, airway  Tetany can occur due to sudden decrease of calcium levels  At risk for seizures and compromised airway issues  Muscular spasms, laryngospasms –  Administer IV Calcium! Keep IV Calcium Gluconate readily available for patients post-op  Monitor I&Os to assess fluid/electrolyte balance  Calcium and Vitamin D supplements  Encourage mobility Tetany

IV Calcium gluconate

High calcium diet

Chvostek's sign

PTH administration

High calcium diet