Endocrine System
What does glucagon do and how?
Increases the release of glycogen from the liver to raise blood sugar.
What is a normal TSH level?
0.4-4 mIU/L (milli international units/L)
Negative Feedback
A type of regulation that responds to a change in conditions by initiating responses that will counteract the change. Maintains a steady state. ✷ Regulates the hormones ✷ Relies on blood level of a hormone ✷ Most common regulator in the endocrine system ✷ Works much like a thermostat. The hypothalamus is the thermostat of the body, constantly monitoring.
Thyrotropin/Thyroid Stimulating Hormone(TSH)
Anterior pituitary hormone that triggers secretion of thyroid hormones by the thyroid gland.
What is the relationship between calcitonin and the parathyroid glands?
Calcitonin, which is released from the thyroid gland, decreases blood calcium levels when they become too high. The parathyroid gland is what increases blood calcium levels by releasing the parathyroid hormone(PTH).
Hyperparthyroidism: Characterized by, goals, treatment
Characterized by ⬆︎ PTH ⬆︎ Ca⁺⁺ ⬇︎ PO₄ ⬆︎ ♡ function (⬆︎ contractility) Goals ✷ Relief of symptoms ✷ Prevent complications caused by ⬆︎PTH (hypercalcemia, hypophosphatemia) Treatment ✷ Parathyroidectomy ✷ Nonsurgical treatment
A hormone is a _____________ that is __________________________ and has a ____________.
Chemical substance; produced in the body; target
Hyperparathyroidism - Nonsurgical Treatment
Conservative approach if asymptomatic or mild s/s Meds to help ⬇︎ Ca⁺⁺ levels ◇ Biphosphonates To inhibit osteoclastic bone resorption alendronic acid (Fosamax) ◇ Calcitonin To pull Ca⁺⁺ from blood into bone ◇ Calcimimetics To ⬇︎ PTH secretion and Ca⁺⁺ levels (Cincalcet -- approved only for parathyroid cancer or secondary hyperparthyroidsim in pt with CKD on dialysis) Increase fluids To remove kidney stones Diuretics Annual Exam ◇ PTH, Ca⁺⁺, and phos levels ◇ BUN & Creatinine (stones!) ◇ X-rays and DEXA scans
Hyperthyroidism: Definition, s/s, treatment, goals
Definition Hyperfunction. Too much thyroid hormone. Grave's Disease is the most common cause. Signs & Symptoms ✷ FAST!!! ✷ All VS are high: ⬆︎T, ⬆︎BP, ⬆︎RR, ⬆︎P ✷ Diarrhea, decreased weight, energizer bunny, insomnia ✷ Exophthalmos (bulging eyes) Treatment ✷ Cut it out Thyroidectomy. Spare the parathyroids though, or you will deal with Ca⁺⁺ issues ✷ Monitor the heart Give cardizem or inderal as ordered ✷ Suppress with drugs SSKI, Iodine, antithyroid drugs, beta-blockers ✷ Radioactive Iodine (RAI) ✷ Eye moisture, cool dark room Goals ✷ Experience relief of symptoms ✷ No serious complication r/t disease treatment ✷ Maintain nutritional balance ✷ Cooperate with therapeutic plan
Hypothyroidism: Definition, s/s, treatment, goals, patient teaching
Definition Hypofunction of the thyroid. Thyroid hormone is low. Early Symptoms: ✷ SLoooOOOoooW... so tired, so cold. ✷ Being more sensitive to cold, constipation, depression, fatigue or feeling slowed down, heavier menstrual periods, joint or muscle pain, paleness or dry skin, thin, brittle hair or fingernails, weakness, hair loss ✷ All VS are decreased: ↓T, ↓P, ↓RR, ↓BP Late Symptoms: Subnormal temp, bradycardia, weight gain, decrease LOC, thickened skin, cardiac complications *** The thyroid can be small or large (goiter) depending on the cause of the disorder. Treatment: ✷ Screen high risk populations ✷ Mostly outpatient therapy myxedema coma necessitates acute care ✷ Thyroid drug ✷ Warm environment Goals ✷ Experience relief of symptoms ✷ Maintain a euthyroid (normal) state as evidenced by normal T₃ & T₄ levels ✷ Maintain a positive self-image (myxedema) ✷ Comply with lifelong thyroid replacement therapy Patient Teaching ✷ S/S of both hypo- and hyperthyroidism ✷ Regular follow-up care ✷ Emphasize need for warm environment ✷ Measures to prevent skin breakdown ✷ Avoid sedatives or use lowest dose possible ✷ Measures to minimize constipation Stool softener, increased liquids, fiber, exercise. Avoid use of enemas
Thyroidectomy: Definition, pre-op care, patient teaching
Definition ✷ Excision of thyroid gland ✷ Usually almost sub-total thyroidectomy 80% to < 90%. Hopefully remaining thyroid will secret T₃ & T₄ Pre-op Care ✷ Administer meds to achieve euthyroidism ✷ Administer iodine to decrease vascularity Patient Teaching ✷ Comfort and safety measures Cut right across the neck. Support head, gentle ROM ✷ Routine post-op care ✷ Talking likely to be difficult post-op ✷ Monitor hormone balance periodically ✷ Reduce caloric intake (or they will gain weight) ✷ Adequate but not excessive iodine intake ✷ Regular exercise ✷ Avoid ⬆︎environmental temperatures ✷ s/s of hypothyroidism
Parathyroidectomy: Defintion, post-op
Definition ✷ Partial or complete removal of glands (Remove 3¹/₂). Subtotal parathyroidectomy. ✷ Most commonly done endoscopically ✷ Leads to rapid reduction of Ca⁺⁺ levels Post-Op: What do nurses do? ✷ Observe for s/s of respiratory distress Emergency equipment at bedside ✷ Hypocalcemic crisis or laryngeal nerve damage can occur ✷ Routine post-op care ✷ Teach pt about s/s of hypocalcemia
The patient with low PTH, low calcium, and increased phosphate most likely has...
Hypoparthyroidism
The ______________ stimulates the _________________ to secrete ________ which in turn stimulates the thyroid gland to release __________.
Hypothalamus; anterior pituitary; TSH; T₃ & T₄
Thyroidectomy: Post-op Care
Monitor for complications ✷ Hypocalcemia The parathyroid glands are in the thyroid and without them/or fewer of them they may not produce calcium. Watch for numbness & tingling around the lips ✷ Hemorrhage The thyroid gland is highly vascular ✷ Laryngeal nerve damage Vocal cord damage, trach damage ✷ Thyrotoxic crisis ✷ Maintain patent airway/monitor for airway obstruction Emergency equipment at bedside (suction, O₂, trach tray) ✷ Monitor for laryngeal stridor Be concerned! Airway obstruction ✷ IV calcium readily available ✷ Assess for signs of hemorrhage or tracheal compression Difficulty breathing, feeling of fullness at neck, check dressing, too much swallowing??? They could be swallowing blood. Q2 hours during first 24 hours. ✷ Semi-Fowler's position; support head with pillows ✷ Avoid neck flexion and tension on suture line ✷ Monitor VS & Ca⁺⁺ levels
Parathyroid Glands
Four pea-sized glands found on back of thyroid gland. Produce and secrete parathyroid hormone(PTH), the major hormone involved in regulation of blood calcium levels.
Hormonal Stimulus
Hormone release caused by another hormone (a tropic hormone).
Myxedema; Myxedema Coma
Myxedema Patients with severe, long-standing hypothyroidism may display myxedema, which alters the physical appearance of the skin and subcutaneous tissues with puffiness, facial and periorbital edema, and a masklike affect. Myxedema Coma The mental sluggishness, drowsiness, and lethargy of hypothyroidism may progress gradually or suddenly to a notable impairment of consciousness or coma. This situation, termed myxedema coma, is a medical emergency. Myxedema coma can be precipitated by infection, drugs (especially opioids, tranquilizers, and barbiturates), exposure to cold, and trauma. It is characterized by subnormal temperature, hypotension, and hypoventilation. Cardiovascular collapse can result from hypoventilation, hyponatremia, hypoglycemia, and lactic acidosis. For the patient to survive myxedema coma, vital functions must be supported and IV thyroid hormone replacement administered.
Neural Stimulus
Nerve fibers stimulate hormone release.
Tropic Hormones
_____________ stimulate other endocrine glands to secrete hormones.
Hormones
__________________ are chemical messengers that are produced in one body region but affect a different body region.
Thyroid Storm (Thyrotoxic Crisis)
✷ A relatively rare, life-threatening condition caused by exaggerated hyperthyroidism ✷ Death within 48 hours if not treated
Hyperthyroidism -- Acute Thyrotoxicosis: What do nurses do?
✷ Administer meds to block thyroid hormone production and SNS ✷ Monitor for dysrhythmias ✷ Ensure adequate oxygenation ✷ F&E replacement ✷ Ensure adequate rest Can be really difficult to do. Dim lights, reduce noise, room at the end of the hall, cool room, cluster care
Hyperthyroidism -- Exophthalmos: What do nurses do?
✷ Artificial tears ✷ Salt restriction Help with edema ✷ Elevate HOB ✷ Dark glasses Photophobia and a protective barrier ✷ Tape eyelids closed if needed for sleep ✷ ROM of intraocular muscles ✷ May need steroid and/or diuretic therapy
What are some causes of hypofunction in then endocrine system?
✷ Autoimmune destruction ✷ Neoplasm (cancer) ✷ Infection ✷ Ischemic damage, profound hypotension ✷ Altered hormone synthesis
Graves Disease
✷ Autoimmune disease ✷ Hyperthyroidism ✷ Antibody: Thyroid stimulating hemoglobin ✷ TSH attaches to thyroid cells and stimulations production of thyroid hormone Symptoms Intolerance to heat, heart palpitations, sensitivity to light, weight loss, appetite increase, easily agitated, protruding eyes.
Thyroid Stimulating Hormone (TSH or Thyrotropin)
✷ Hormone of anterior pituitary ✷ Normal level is 0.4-4 mIU/L ✷ Chemical Class: Glycoprotein ✷ Stimulates thyroid hormone release
Goiter
✷ Iodine deficiency that causes thyroid to enlarge as it tries to produce thyroxine ✷ Can be hypo- or hyper- or any thyroidism
What are some causes of hyperfunction in the endocrine system?
✷ Neoplasia, hyperplasia ✷ Autoimmune disorders ✷ Exogenous hormones (prednisone) ✷ Altered target tissue responses
Iodine
✷ Potassium Iodine (SSKI) & Lugol's Solution ✷ Inhibits synthesis of T₃ & T₄ and block their release into circulation ✷ Decreases vascularity (bleeding) of thyroid gland ✷ Maximal effect within 1 to 2 weeks ✷ Used before surgery to treat crisis (thyroid storm) ✷ Mix with water or juice; have pt sip through straw (it will stain their teeth)
Antithyroid Drugs (Thioamides)
✷ Prophylthiouracil (PTU) & methimazole ✷ Inhibits synthesis of thyroid hormone ✷ Improvement in 1 to 2 weeks and good results in 4 to 8 weeks ✷ Cardiovascular adverse effects Might not be good for an older patient ✷ Therapy for 6 to 15 months To allow for spontaneous remission
How do β-adrenergic blockers help with hyperthyroidism?
✷ Symptomatic relief Will not treat it, but will help the pt to feel better ✷ Blocks effects of sympathetic nervous stimulation ✷ Propranolol Usually administered along with antithyroid agents ✷ Atenolol Preferred for pts with a history of asthma or heart disease
Facts about the Thyroid
✷ The thyroid makes calcitonin ✷ Calcitonin deposits Ca⁺⁺ to the bone (Cal-ci-"bone-in") ✷ Iodine is need to make thyroid hormone ✷ An overactive thyroid gland uses/uptakes a lot of iodine
What is the difference between primary and secondary hyperthyroidism?
✷ T₃ & T₄ are high no matter what Primary (thyroid gland) TSH is ⬇︎ T₃ & T₄ are ⬆︎ This is b/c negative feedback is working. The hypothalamus is aware there is plenty of thyroid hormone so it isn't asking for any Secondary (pituitary gland) TSH is ⬆︎ T₃ & T₄ are ⬆︎ This is b/c the pituitary gland is asking for more TH to continue to be produced
What is the difference between primary and secondary hypothyroidism?
✷ T₃ & T₄ are low no matter what Primary (thyroid gland) TSH is ⬆︎ T₃ & T₄ are ⬇︎ Secondary (pituitary gland) TSH is ⬇︎ T₃ & T₄ are ⬇︎ In secondary, the pituitary gland isn't asking for any
What are the 3 hormones produced and secreted by the thyroid gland?
✷ T₃ (Triiodothyronine) More potent but less abundant than T₄ ✷ T₄ (Thyroxine) More abundant but not as potent as T₃ ✷ Calcitonin
Hypoparathyroidism: Characterized by, s/s, treatment, what do nurses do?
✷ Uncommon ✷ Usually occurs inadvertently when parathyroid glands are accidentally removed during surgery Characterized by ⬇︎ PTH, ⬇︎ Ca⁺⁺, ⬆︎PO₄ ⬇︎❤︎ function S/S Clinical manifestations are due to hypocalcemia Treatment Give a drug (calcium) What do nurses do? ◆ Administer IV Ca⁺⁺ for emergency tx of tetany ・Calcium gluconate ・Calcium chloride ・Calcium gluceptate ◆ Rebreathing may partially alleviate acute neuromuscular symptoms of hypocalcemia ◆ Teach patient about lifetime management with PO Ca⁺⁺ supplements and Vitamin D
What 2 hormones work together to regulate calcium balance?
PTH & calcitonin
Humoral Stimulus
Secretion of hormones in direct response to changing blood levels of ions and nutrients.
Parathyroid Gland and Blood Calcium Homeostasis
The parathyroid glands produce and secrete PTH, a peptide hormone, in response to low blood calcium levels. PTH secretion causes the release of *calcium* from the bones by *stimulating osteoclasts*, which secrete enzymes to degrade bone and release calcium into the intersitial fluid. PTH also inhibits osteoblasts, the cells involved in bone deposition, thereby sparing blood calcium. PTH causes increased reabsorption of calcium(and magnesium) in the kidney tubules from urine filtrate. In addition, PTH initiates the production of the steroid hormone *calcitriol*, which is the active form of vitamin D3, in the kidneys. Calcitriol then stimulates increases absorption of dietary calcium by the intestines which increases blood Ca2+ levels. A negative feedback loop regulates the levels of PTH, with rising blood calcium levels inhibiting further release of PTH.
Levothyroxine (Synthroid, Levoxyl)
What it is Synthetic thyroid hormone Very predictable. Works much in the same way as the thyroid. Dosing ✷ Start with low dose then closely monitor the patient ✷ Increase does in 4- to 6-week intervals as needed ✷ Watch out: Dose is in mcg but it is often supplied in mg ✷ Medication is effective with a goo pul Monitor For: ✷ CV side effects, weight loss, nervousness, tremors, insomnia Patient Teaching ✷ Take in AM, with full glass of water, on an empty stomach ✷ Take at the same time every day ✷ Don't switch brands without physician approval ✷ Side effects ✷ Report any unusual s/s, CP, or palpitations ✷ Check before taking OTC meds ✷ May increase effects of Warfarin ✷ Therapeutic effects may take several months to occur ✷ Therapy needs to be lifelong
Radioactive Iodine Therapy (RAI): What it is, when it's given, patient teaching
What it is ✷ I-131 When it's given ✷ Option when drugs don't work ✷ Usually given on an outpatient basis Patient Teaching ✷ Drink normal amount of fluids ✷ Radiation precautions Use private toilet for three days, flush two times every time you pee, wash utensils separately, no intimate contact for three days, sleep in separate room ✷ Oral care for thyroiditis/paroditis ✷ Symptoms of hypothyroidism Works so well the pt winds up with hypothyroidism & take levothyroxine for the rest of their lives Review Purple Handout