week 8- hyper and hypo thyroidism Flashcards
The thyroid makes thyroid hormone (T3 & T4)
Controls metabolism
Balances calcium and phosphorus
Regulated by the Hypothalmic-Pituitary-Thyroid negative feedback loop
Need dietary intake of protein & iodine to produce TH
Thyroid hormones affect all body cells, specifically:
—Effects on growth, metabolic rate and specific body mechanisms
—T3 & T4 increase metabolism=increased O2 consumption and heat production in all tissues (Iggy, 2010)
conversion of T’S
T4 converts to T3 in the cell
Conversion is impaired by: stress, starvation, dyes, beta blockers, amiodarone, corticosteroids, and PTU
Functions of TH
Fetal development
Control metabolic rate
Growth hormone and gonadotropins (pituitary)
Regulates protein, carb and fat metabolism
Chronotropic and inotropic cardiac effects (rate and force of contraction)
Increases RBC production
Affects resp rate and drive
Increases bone formation and decreases bone resorption of calcium (through calcitonin release)
Acts as insulin antagonist
Thyroxine (T4)
-influences metabolic rate, regulates lipid & carbohydrate metabolism
Triiodothyronine (T3)-
help regulate growth development, metabolism and controls heat regulation (thermoregulating center)
Calcitonin-
responds to hypercalcium, lowers plasma calcium and phosphate levels, inhibits reabsorption of calcium into bones
Responsible for maintaining adequate levels of calcium in the extracellular fluid
Thyroid gland communicates with parathyroid gland that lies above and behind it.
Iodine and tyrosine(amino acid) is essential for proper functioning of thyroid glands which generally is acquired in sufficient amounts from our diet.
T3 &T4 are stored with thyrogloblin (a protein that contains tyrosine and amino acid) in the follicles in the thyroid gland called colloids
When thyroid gland is signaled it will release T3 & T4 into the circulation system. Low blood level will trigger TSH (thyroid stimulating hormone) known as thyrotropin.
Negative Feedback Loop
Hypothalamus produces and secretes thyrotropin-releasing
hormone (TRH)
—->
TRH stimulates the anterior pituitary to secrete thyroid stimulating hormone (TSH)
—>
TSH stimulates the thyroid gland to increase production of
T3 (triiodothyronine) and T4 (thyroxine)
neg feedback looop
If the thyroid hormone (T3 & T4) levels get too high, the hypothalamus decreases secretion of TRH and the pituitary decreases secretion of TSH
If the thyroid hormone (T3 & T4) levels get too low, the hypothalamus increases secretion of TRH and the pituitary increases secretion of TSH
So….
Hyperthyroid = HIGH T3 & T4 and LOW TSH
Hypothyroid=LOW T3 & T4 and HIGH TSH
Thyroid Disease
Hypothyroidism more common that hyperthyroidism
Women affected > men
Symptoms of thyroid disease extremely variable
New onset or a change in symptoms important
May develop quickly or slowly
Only blood tests confirm diagnosis
Iodine deficiency in undeveloped countries most common cause of hypothyroidism = goiter (enlarged thyroid gland)
Iodine added to salt in many countries
Thyroid Disease: Causes
-Primary Causes
Autoimmune disorders
Graves’ Disease (hyperthyroidism)
Hashimoto’s Thyroiditis (hypothyroidism)
• Secondary Causes
Pituitary tumours, surgery, irradiation, medications
Plummer’s disease (toxic nodular disease “hot nodule”)
Multinodular disease
Graves’ disease affects mostly women and between age
20-40.
Hyperthyroid
s&s
Low energy Fatigue-trouble awakening in am, need more sleep, falls asleep during the day Feeling cold when others feel warm Less sweating Dry, itchy skin Dry, coarse, brittle hair Increased hair loss (thinner) Loss of outer third of eyebrow Loss of appetite Mild weight gain (5-15 lbs), difficulty losing weight ** does not cause obesity New or worsening memory problems and slowed thinking New snoring More frequent muscle cramps and joint aches New feeling of pins and needles in hands and feet (parasthesia) New constipation New puffiness around the face (especially eyes), hands, feet and ankles Carpal tunnel Heavier and/or more frequent periods, worse cramps, worse premenstrual symptoms Feeling irritable New depression New hoarse voice New hearing loss Goiter (enlarged thyroid gland)-most common with Hashimoto’s thyroiditiis Shrinking thyroid Decreased HR-decreased blood flow and O2 delivery to tissues Slight increase in BP Higher cholesterol levels Slow reflexes Heat intolerance* Diaphoresis/smooth moist skin Hair loss Weight loss with increased appetite Nervousness & tremors Palpitations, tachycardia, Atrial fib Insomnia Goiter Menstrual irregularities (-) Hypertension Frequent bowel movements*
Hypothyroid
s&S
Cold intolerance Dry coarse skin Hair loss Weight gain with poor appetite Fatigue/lethargy Bradycardia Hypersomnia Goiter Menstrual irregularities (+) Slow thinking/memory Constipation* Tachycardia/palpitations Chest pain Increased SBP Dysrhythmias Muscle weakness/wasting Blurred or double vision Eye fatigue Corneal ulcers or infections Increased tears/redness/photophobia Eyelid retraction/eyelid lag**Graves’ disease only Globe lag** Wide-eyed startled look Hyperactive tendon reflexes Low grade fever
Assessment
When patient reports general symptoms of fatigue or unplanned weight change and depression or anxiety, be sure to ask about other S &S related to thyroid disorders that they may not automatically mention
Nutrition, elimination, sleep-rest pattern, sexuality-reproductive & activity-exercise assessments (Iggy, 2010)
Head-to-toe assessment-affects all body systems
Inspect and palpate thyroid gland (See Jarvisnot usually part of a routine nursing assessment)
Review diagnostic test results
Discuss life impact (ie: work, activity, relationships)
When patient reports general symptoms of fatigue or unplanned weight change and depression or anxiety, be sure to ask about other S &S related to thyroid disorders that they may not automatically mention
Nutrition, elimination, sleep-rest pattern, sexuality-reproductive & activity-exercise assessments (Iggy, 2010)
Head-to-toe assessment-affects all body systems
Inspect and palpate thyroid gland (See Jarvisnot usually part of a routine nursing assessment)
Review diagnostic test results
Discuss life impact (ie: work, activity, relationships)
Diagnostic Testing
• TSH is the most sensitive test of thyroid function
o Decreased TSH = hyperthyroidism
o Increased TSH = hypothyroidism
• T4 testing may help differentiate sub-clinical (mild)disease
• Imaging tests-ultrasound, Radioactive Iodine Scan
• Fine needle biopsy
• CBC, lipid profile, metabolic profile
• ECG
Ultrasound: info about solid vs cystic nodules, info about benign vs malignant tumours (looks at border edges, vascularity, presence of microcalcifications),
RAI Scan: identify whether nodule is “hot” (more likely benign) or “cold” (more likely malignant)
Pts with hypothyroidism may also have iron deficiency anemia, dyslipidemia, hyponatremia, and decrease GFR
Toxic Nodular Disease “hot nodule”
• This scan shows a solitary “hot” nodule located in the left lobe
• This single nodule is comprised of thyroid cells which have lost their regulatory mechanism that dictates how much hormone to produce
• Without this regulatory control, the cells in this nodule produce thyroid hormone at a dramatically increased rate causing symptoms of hyperthyroidism
• Some nodules are “cold” since they
o don’t produce any hormone at all
Risk Factors: Hypothyroidism
Family history Personal history of thyroid disease Women over 50 & the elderly History of autoimmune diseases 6 weeks to 6 months postpartum or during menopause White or Asian
One of the most common thyroid disorders
Affects people worldwide regardless of age, sex, race, wealth, education
Almost half of people with hypothyroidism don’t know it
Treatment: Hypothyroidism
- Synthetic thyroid hormone replacement for life
- Levothyroxine once daily
- Long half-life (7 days)
- Dose slowly increased until thyroid hormone levels normal
- Goal of thyroid replacement therapy is to keep TSH in the low normal range (euthyroid)
- Dosage based on age, weight, and cardiac status
- **use caution in patients with cardiac disease
- *Bowel movement regularity an important guide to therapeutic effect
- Full effect expected in 4-6 weeks
Patient Teaching: Hypothyroidism Treatment
Levothyroxine absorption affected by:
• Dietary fibre
• Antacids
• Iron
• Calcium
• Take with full glass of water
• Best one hour before breakfast
• Same time daily
• Consult HCP before taking other OTC medications
• **over-replacement is biggest problem (know hyper S & S!)
• Do not stop taking abruptly – causes rebound effects
• Monitor for CV disease and symptoms
• Use cautiously with Coumadin*report bruising or bleeding (increases the effects of Coumadin)
Myxedema Coma
Sudden drop in thyroid hormone
Due to undiagnosed or untreated hypothyroidism or incorrect treatment (inadequate dose, pt stops taking his/her medications suddenly)
Or precipitated by: trauma, infection, or surgery
Rare but often deadly
Risk Factors: new-onset HF, recent stroke, use of amiodarone, lithium, phenothiazines, tranquilizers
Myxedema Coma: S & S
Exaggerated hypothyroidism S & S Weakness Confusion (untreated, leads to coma) Hypothermia (severe) Edema Breathing difficulties Most common in older women in winter months **mental status and respiratory assessment a priority
Myxedema Coma: Treatment
Administer oxygen
Ventilator support
Levothyroxine IV initially
Nursing Diagnoses
Ineffective breathing pattern related to decreased energy, weight gain and fatigue
Decreased cardiac output related to altered heart rate and rhythm
Disturbed thought processes related to impaired brain metabolism and edema
Treatment: Hyperthyroidism
More complicated than hypothyroidism
Managed by an endocrinologist
Treatment Options: Radioactive Iodine therapy (RAI) (treatment of choice) Antithyroid medications Iodine products Surgery Beta-blockers
Radioactive Iodine Therapy
Oral doses are absorbed quickly by the stomach and intestines, then carried in the bloodstream to the thyroid, where it is taken up by the gland.
Radioactive iodine only affects the thyroid gland. Thyroid cells are the main target in the body that can absorb iodine, so there is very little radiation exposure to the rest of the body’s cells.
While in the thyroid gland, the RAI disrupts the function of some of the thyroid cells - the more radioactive iodine given, the more cells cease to function.
As the cells stop functioning, excessive amounts of thyroid hormones are no longer produced, and symptoms of hyperthyroidism begin to disappear with the risk of hypothyroidism. (It might seem odd to replace one disorder with another, but hypothyroidism is much easier to treat on a long-term basis than hyperthyroidism. )
RAI
• Concentrates in thyroid and destroys tissue
• Patients eventually develop hypothyroidism and need thyroid replacement therapy
• Effectiveness monitored q 4-6 weeks
• RAI is shed in stool, urine, saliva -precaution is necessary
• Avoid body fluid contact with others for 48-72 hours after treatment
• Double flush toilet
• Contraindicated with:
o Pregnancy (delay until 6 months post-treatment)
o Breastfeeding
Radioactive Iodine Uptake Test –=
measures absorption by the thyroid gland (calculated dose given (po or IV), thyroid is scanned in 24hr of distribution of RAI
The iodine is concentrated in the thyroid gland
The dose of radiation with these tests is very small and has no major side effects to the patient
Special precaution when nursing these patients – isolation rooms, avoid contact with body fluids
RAI is excreted in the urine, stool and saliva
A Special Caution for Women
Pregnant women or women who want to become pregnant in the next 6 months should not use radioactive iodine, as the treatment can destroy the fetus’s thyroid and impair its development.
Women should wait a year before conceiving if they have been treated with the therapy.
Women who are breast-feeding should also not use radioactive iodine.
Thionamides
Propylthiouracil (PTU) and methimazole
For mild disease or contraindications to RAI
Used in hyperthyroidism to prevent the surge of thyroid hormones that occurs after surgical treatment or during radioactive iodine treatment
Given over 12-18 months
Risk of relapse
Patients assessed every 3 months
Side effects - May cause liver and bone marrow toxicity
Iodine Therapy
Inhibits thyroid hormone release Rapid onset Often used to treat thyrotoxicosis or thyroid storm Adjunct therapy for RAI Can be used prior to surgery Eg: potassium idodide Effects last only a few weeks
Surgery
• Removal of entire thyroid gland or subtotal thyroidectomy
• Risk of complications
o Hemorrhage, laryngeal edema, vocal cord paralysis
• Used when RAI contraindicated or patient preference
o Pregnant or planning to be in next 6 months
Post surgery: Hypothyroidism -
This more often occurs when the entire thyroid is removed, but it can still happen when only part of the thyroid is removed.
To compensate for the lack of thyroid hormones, the patient will take thyroid replacement therapy for life
Hypocalcemia:
the body may be more prone to a temporary period of hypocalcemia that responds well to oral calcium supplements with full recovery.
Occurs because hyperthyroidism can deplete the body of its normal calcium stores before surgery, and it takes some time to replenish this after surgery
Beta-Blockers
• Adjunctive therapy • Patients with atrial fibrillation with rapid ventricular response • May also reduce : o Body temperature o Diaphoresis o Tremors o Palpitations o Anxiety
Graves’s Eye Disease
• Findings only seen with hyperthryoidism caused by Graves’ disease
• Exophthalmos
o Wide-eyed, startled look
o Lid retraction
o Globe and lid lag
o May have impaired vision
o Dry eyes (lid cannot close)-risk for corneal abrasion, infection
o Redness, tearing, bloodshot, photophobia
Opthalmopathy
- Treatment for hyperthyroidism does not improve the eye and vision problems
- Treatment is symptomatic
- Elevate the head at night
- Eye lubricant
- Dark Glasses for photophobia
- Steroids or Diuretics may be used
Thyroid Storm
- Due to too much thyroid hormone (induced by stress, infection, too high dose of thyroid medication or overdose of thyroid medication)
- Exaggerated hyperthyroidism S & S
- Mainly due to increased metabolic rate and oxygen demands
- Extreme temperature (40.7 C)**cardinal sign
- Severe tachycardia
- Cardiac dysrrhythmia, HF and shock
- Restless, agitation, seizures
- N & V & D
- Weakness & confusion or disorientation
Thyroid Storm: Treatment
Continuous cardiac monitoring Supplemental oxygen IV access for fluid resuscitation Risk of hypovolemic shock Monitor intake and output to ensure accurate fluid replacement Administer PTU or methimazole and iodine Beta-blockers Ice packs & cooling blankets Acetaminophen Monitor cardiac rhythm, VS, I & O
Hyperthyroid: Nursing Assessment and Management
• Assess apical pulse, BP and temperature q 4h
• Teach patient to report palpitations, dyspnea, vertigo, chest pain
• Immediately report temperature increase of 0.6°C
o (ie: 37°C increases to 37.6° C)
• Assess cardiac status
• Reduce stimulation
• Promote comfort
• Administer meds as ordered
Nursing Diagnoses: Hyperthyroidism
- Imbalanced nutrition: less than body requirements
- Hyperthermia related to increased metabolic rate
- Fatigue related to sleep deprivation
- Potential for hypertension and cardiac failure
Thyroid Disorders: Nursing Considerations
• Ensure patient aware of long term nature of therapy and follow up, especially with changes to health status
• Teach S &S of hypo and hyperthyroidism
• Monitor TSH level every 6-8 weeks until normal
• Monitor TSH annually thereafter or if S & S reported
• TSH level normal range 0.5 to 5 mU/L
• Teach S & S of complications & when to call 911
• Monitor/assess for:
o Anemia, hyperlipidemia, depression, menstrual changes, abnormal BP, electrolyte disturbances, blood glucose changes
