Exam 3: Thyroid Flashcards
Hyperthyroidism
Hyperactivity of the thyroid gland with sustained increase in synthesis and release of thyroid hormone
Causes: Grave’s disease (autoimmune), toxic multinodular goiter, toxic adenoma, thyroiditis, excessive ingestion of exogenous TH
Manifestations:Tremor of hands, irritability, palpitations, diaphoresis, tachycardia, SOB, exophthalmos, increased appetite, weight loss, diarrhea, heat intolerance
Labs: Decreased TSH, increased T4, increased radioactive iodine uptake
Diagnosis: Ultrasound, thyroid scan, EKG
Pathophysiology of Grave’s disease
Autoimmune disorder, development of TSH-receptor antibodies that stimulate thyroid to release T3, T4, or both
Excessive release of hormones leads to clinical manifestations
Periods of exacerbations and remissions
May progress to complete destruction of thyroid tissue and cause hypothyroidism
Characteristics: Hyperthyroidism, Goiter, Ophalmopathy (Exophthalmos). Dermopathy (pretibial edema = less common)
Treatment of hyperthyroidism
Goals: Block adverse effects of excessive thyroid hormone, suppress over-secretion of thyroid hormone, prevent complications
Treatment: Antithyroid medications, radioactive iodine therapy, beta blockers, surgical interventions
Nutritional therapy: High calorie, high protein, high carbohydrate, avoid foods that increase metabolism (spicy, high fiber, caffeine)
Antithyroid drugs: Thiomides
Inhibits synthesis of hormones
Adverse effects: Thyroid suppression, liver toxicity, bone marrow suppression
Monitor: Labs: Thyroid, LFTs, CBC. S/S of hypothyroidism
Adjuvant Therapy: Iodine
Use: Along with other antithyroid drugs to prepare PT for thyroidectomy or prevent/treat thyroidtoxicosis (thyroid storm); Decreases vascularity of the thyroid gland, making surgery safer and easier
Action: Administration of large doses of iodine rapidly inhibits synthesis of T3 and T4; blocks the release of hormones in the circulation
Adverse effects: Most common: Hypothyroidism, iodine toxicity (metallic taste, burning mouth, sore teeth/gums, n/v/d, confusion, coma), mucosal injury and hemorrhage with Lugol’s solution, contraindicated in pregnancy
Teaching: Give iodine through a straw, increase palatability when given in milk or fruit juice
Adjuvant Therapy: Beta Blocker (symptom management)
Decrease HR, decrease systolic BP, decrease muscle weakness, decrease tremors/anxiety/heat intolerance
PT continues to take medication until free T4 and TSH levels approach normal
Radioactive Iodine (RAI) Therapy
Goal: Eliminate hyperthyroid state with ONE sufficient radiation in a single dose
Adverse effects: Symptoms of thyroid storm or thyrotoxicosis, contraindicated in pregnancy (pregnancy test 48 hours prior, do not conceive for 6 months after therapy, can’t be administered until 6 weeks after lactation stops)
CV patients: Treated with antithyroid medications FIRST 4-6 weeks prior to RAI therapy
Thyroid hormone replacement: Needed 4-18 weeks after the antithyroid medication has been stopped based on thyroid function tests
Education: Contamination of household, avoid sleeping or having sex with others, avoid close contact with children or pregnant people, do not share utensils or cups
Surgical management for hyperthyroidism
Subtotal thyroidectomy, total/radical thyroidectomy, endoscopic thyroidectomy
Indications: Large goiter causing tracheal compression, unresponsiveness or allergy to antithyroid medication, thyroid cancer, when PT is not a candidate for RAI
Post-op monitoring: Hypothyroidism, edema, hemorrhage, injury to laryngeal nerve (vocal cord disturbed), airway obstruction leads to laryngeal stridor and restlessness, removal of parathyroid glands
Hypoparathyroidism
Manipulation/removal of the parathyroid gland during surgery (most common)
Low magnesium (reversible)
Autoimmune attach (common)
Labs: Low calcium, low PTH, high phosphorus
Symptoms: Tingling of extremities and around mouth, seizures
Hyperparathyroidism
Primary: Too much PTH
Secondary: CKD, severely low calcium or vitamin D intake
Labs: High calcium, high PTH, low phosphorus
Symptoms: Bone thinning and kidney stones
Hypocalcemia
Risk factors: Hypoparathyroidism, malabsorption, osteoporosis, pancreatitis, alkalosis, transfusion of citrated blood, kidney injury, medications
Manifestations: Tetany paresthesias, Trousseau sign, Chvostek sign, seizures, dyspnea, laryngospasm, abnormal clotting, anxiety
Monitor: Perfusion, cognition, GI/elimination
Calcium replacement: IV piggyback of Calcium Gluconate for emergency, oral calcium and vitamin D supplements
Seizure precautions
Hypercalcemia
Risk factors: Malignancy and hyperparathyroidism, bone loss (immobility), diuretics
Manifestations: Polyuria, thirst, muscle weakness, intractable nausea, abdominal cramps, severe constipation, diarrhea, peptic ulcer, bone pain, ECG changes, dysrhythmias
Monitor: Perfusion (EKG), cognition, GI/elimination
Treat underlying cause, fluid replacement
Falls precautions
Thyroid Storm/Crisis
Extreme and life-threatening form of thyrotoxicosis
Abrupt onset, mortality rate high if untreated
Causes: Stress such as Grave’s disease, trauma, infection, DKA, or during thyroidectomy
Symptoms: Hyperpyrexia > 101.3ºF (38.5ºC), tachycardia >130 BPM, hypertension, dyspnea, chest pain, palpitations, exaggerated symptoms of hyperthyroidism, severe CNS effects (agitation, restlessness, delirium)
Management: Rapid diagnosis and treatment, hypothermia blanket, cool sponge bath, cool environment, humidified oxygen, monitor ABGs, IV fluids with dextrose, propylthiouracil, hydrocortisone, iodine, beta blocker
Hypothyroidism
Thyroid hormone deficit, hypometabolic state
Causes: Acquired primary, secondary, or tertiary hypothyroidism, congenital hypothyroidism (cretinism) in children, autoimmune thyroiditis (hashimoto’s), lithium or amiodarone, post-treatment of hyperthyroidism
Manifestations: Constipation, depression, bradycardia, weight gain, swelling in face/tongue/hands/feet, cold intolerance
Diagnosis: Thyroid scan, EKG, low serum T4, elevated TSH
Treatment: Levothyroxine
Congenital hypothyroidism
Causes cognitive impairment and impairs physical growth
S/S (untreated): Jaundice, long-term cognitive impairment, respiratory difficulty, hoarse cry, enlarged tongue, feeding difficulties, sluggishness, lack of interest, somnolence
Decreased incidence due to routine neonatal screening (high TSH levels and low to normal thyroid hormone levels)
Treatment: Hormone replacement
Acquired hypothyroidism
Occurs most frequently in females 30-60 years old
May be mild, few s/s but may progress to life-threatening state: Myxedema coma
Primary hypothyroidism
Destruction or dysfunction of the thyroid gland
Most common type of hypothyroidism
Levothyroxine
Synthetic salt of T4, increases metabolic rate of body tissue
Administer: First thing in AM, empty stomach, 30 minutes before breakfast. Higher dose may be needed in pregnancy and childhood
Adverse effects: Symptoms of hyperthyroidism, cardiac dysrhythmias, hypertension, CNS stimulation symptoms (anxiety, sleeplessness, headache)
Monitor: TSH, FT4 regularly
Teaching: Lifelong medication, take on empty stomach
Nursing interventions for hypothyroidism
Monitor: CV change (BP, edema, dysrhythmia), weight
Increase activity levels gradually
Low calorie, high bulk food
Encourage fluids, stool softeners as needed
Provide blankets and warm environment
Myxedema Coma
Rare life-threatening emergency
Decompensated state of hypothyroidism
Precipitated by stress (acute illness or infection, surgery, chemotherapy, discontinuing thyroid replacement therapy)
Initial signs: Depression, diminished cognitive status, lethargy, somnolence, progression from increasing lethargy to stupor
Progressive signs: Hypotension, hypothermia, bradycardia, hyponatremia, hypoglycemia
Manifestations: Depressed respiratory drive, alveolar hypoventilation, progressive carbon dioxide retention, narcosis and coma, CV collapse and shock
Treatments and outcomes of Myxedema Coma
Aggressive and intensive supportive and hemodynamic therapy, Mortality rate high (30-40%)
Patients at greatest risk:
- Older adults (vague symptoms mistaken for aging)
- CV complications
- Reduced consciousness
- Persistent hypothermia
- Sepsis
Treatment: Airway and breathing, circulation (hourly BP and temp, telemetry), 0.9% sodium chloride, treat hypoglycemia, medication support (levothyroxine IV and corticosteroids), check for sources of infection, warm blankets, monitor MS
