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Affects metab., growth, development; temp. regulation, HR, RR (every cell, tissue, organ)
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Endocrine system = "duct system"
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How does it work?
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Negative feedback loop...
- Hypothalamus releases TRH Pituitary releases TSH Thyroid releases T 3 & T4 T3 & T4 maintain normal levels in blood Normal function maintained Normal levels "turn off" hypothalamus |
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Underactive thyroid; not enough T
3 and T4 |
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Primary: dec. thyroid tissue, dec. TH
Secondary: inadequate TSH production |
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Pathophysiology: Low metabolism Hypothalamus & anterior pituitary release TSH TSH tries to get thyroid to release hormones TSH binds to thyroid cells Inability = thyroid gland enlarges Goiter
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Symptoms: (early = fatigue, vague)
- Neuro: memory loss, gait, AMS - CV: low HR, low BP, eye/face edema - Lungs: muscle weakness, dec. effort - GI: dec. bowel, low metab., constipation - Renal: dec. urine output - M/S: weakness, myalgia - Skin: dec. turgor, dry, stiff, puffy, PM - Psych: depression - Reproductive: irregular/heavy periods |
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Drug therapy:
- Levothyroxine (Synthroid) (most common), Liothyronine (Cytomel, Liotrix) Education: - Take first (30 min before/2 hr after meal) - Therapy is LIFELONG! - Don't take within 4 hr of GI meds, antacids - Side effects: signs of hyperthyroidism |
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Most common cause of hypothyroidism
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Cause: immune system attacks thyroid
- Also: dec. iodine, tumor, overtreated |
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Manifestations: dysphagia, enlarged thyroid
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Risk Factors: sex, age, heredity, another autoimmune disorder, radiation
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Complications: goiter, cardiac problems, mental health, myxedema, birth defects
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A medical emergency; "severe" hypothyroidism (r/t untreated, stopping meds)
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Causes: acute illness, surgery (thyroid), chemo, narcotics, d/c replacement therapy
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Presentation:
- Coma - Respiratory failure & hypotension - Hypothermia - Hyponatremia (r/t dec. glomerular fx) - Hypoglycemia (r/t gluconeogenesis) |
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Monitor:
- Labs & electrolyte imbalance(s) - Resp. rate & heart rhythms |
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Interventions:
- Maintain patent airway - Cardiac monitoring - IV: TH replacement, glucocorticoids - Correct electrolytes - Conserve body heat - Narcan? - NO vasoconstrictive drugs - Seizure precautions (r/t low Na & AMS) |
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Increased secretion of thyroid hormones
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Causes:
- Grave's disease (most common) - Multiple thyroid nodules - Toxic multinodular goiter - Excessive thyroid replacement hormones - Thyroiditis - Too much iodine |
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Signs & Symptoms:
- Neuro: tremors, restless, irritable, confusion, seizures - CV: dysrhythmias, a fib. - Lungs: inc. resp. drive = dyspnea - GI: diarrhea, inc. peristalsis, dec. nutrients, losing electrolytes, weight loss - Renal: r/t HTN - M/S: restless & nervousness = fatigue - Skin: smooth skin - Psych: restless, moody, insomnia - Reproductive: issues, irregular periods |
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Interventions:
- Monitor: EKG, HR, RR, VS; thyroid storm - Comfort: calm, cool, comfortable - Diet: avoid iodine, > calories (inc. metab.) - Education: watch for toxicity, med compliance, avoid aspirin |
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Treatment:
Drug therapy: antithyroid meds & radioactive iodine = most common treatment - Thionamides: PTU, Tapazole - Beta-blockers (treat symptoms; HTN, inc. HR, palpitations) - Radioactive iodine (kills thyroid slowly, more permanent cure; not if pregnant or BF) Surgery: to remove all or part of thyroid Combination therapy |
3 & T4; doesn't harm gland; can take in 1st trimester, but can cause liver failure |
Autoimmune; most common cause of hyperthyroidism
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Cause: antibodies attach to TSH receptors inc. # and size of cells thyroid enlarges (goiter) overproduction of hormones
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Additional Manifestations:
- Exophthalmos: autoimmune attacks area behind eyes, causes edema - Pretibial myxedema - Grave's dermopathy: resembles orange peel; r/t inc. protein under skin, legs, & feet |
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What is it? - Extreme exacerbation of hyperthyroidism
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Causes: illness, Grave's disease, meds that inc. TH, untreated/undiagnosed tumor
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Signs & Symptoms:
- Inc. HR & BP = severe cardiac problems - Inc. temp = diaphoresis - Resp. failure - Anxiety or agitation |
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Treatment:
- Interventions to counteract symptoms - Block TH synthesis - Control temp. NO ASA - Meds to suppress immune system? |
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HYPO
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HYPER
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T
3 |
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T
4 |
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TSH = 0.4-4
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TSH Assay
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3, T4, TSH4 to T`3; (+) may indicate autoimmune, not definite for thyroid disease|
Total or subtotal thyroidectomy
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When?
- Large goiter, poor response to drugs - Can't/won't take meds - Malignancy |
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Pre-Op:
- Meds: dec. hormone secretion, beta-blocker, steroids to dec. immune system (w/ autoimmune dx) - Control: HTN, dysrhythmias, tachycardia |
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Post-Op: (BOWTIE)
- B leeding - O pen airway - W hisper - T rach kit & suctioning ready - I ncision (assess/clean dressing & splint) - E mergency - Also: monitor VS, semi-Fowler's, labs, humidify air, diet, cough & deep breathe |
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Complications: hemorrhage, resp. distress, parathyroid injury
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Abnormally low levels of PTH
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Causes:
- Iatrogenic - Idiopathic - Hypomagnesemia (inhibits PTH secretion) - Other: autoimmune |
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Signs & Symptoms:
- P = paresthesias, positive Chvostek's & Trousseau's signs - T = tetany (bronchospams, seizures, EKG) - H = hypocalcemia & hyperphosphatemia |
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Diagnostics:
- EKG = seizure activity, slow brain waves - Blood tests = labs - CT scans = specific compared to US, may show brain calcifications - MRIs may be even more specific |
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Interventions:
- Symptomatic hypocalcemia: give Ca, vitamin D, Mg & seizure precautions - Other meds: phosphate binders, PTH inj. - Monitor: Ca, GI, paresthesias - Education: medication regimen - Diet: inc. Ca |
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Major controlling factor of PTH secretion
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Ca & PTH are directly related
- Increase in PTH = increase in Ca |
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Affects kidneys (regulates P), bones, GI tract
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Abnormally high levels of PTH
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Causes:
- Primary: hyperplasia, cancer growth - Secondary: CKD (PTH overworked = inc. Ca absorbed), vitamin D deficiency |
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Signs & Symptoms:
- B = bones (inc. fractures) - E = epigastric pain, constipation (r/t smooth muscle dec.) - D = dehydration (r/t kidney compensation for inc. Ca) - S = short QT interval (r/t inc. Ca) |
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Interventions:
- Diagnostics - inc. Ca & PTH, dec. P - Monitor: labs, EKG (telemetry) - Diet: dec. Ca, inc. P - watch in renal pt! (already inc. Ca & dec. P) |
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Medications: GOAL = LOWER Ca LEVELS
- Loop diuretics: hypocalcemia = side effect - Biphophates: given for osteoporosis, protect against losing Ca, sit upright for 30 min & w/ full glass of water - Calcimimetics (ex - Sensipar): deceive thyroid that there's enough PTH |
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Education:
- Medication compliance - Monitor for s/s of hypocalcemia - Diet - Prevent complications: osteoporosis, traumatic fractures |
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Labs:
- Calcium (total) = 8.5-10 mg/dL - usually high enough, ionized if specificity desired - Phosphate = 2.7-4.5 mg/dL - Magnesium = 1.3-2.1 mEq/L - PTH = 10-55 picograms/mm |
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Hypoparathyroidism:
- Decreased... Ca, Mg, PTH, vitamin D - Increased... phosphate |
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X-rays
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24-hour urine collection for calcium
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Total or subtotal
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Pre-Op:
- Get Ca in check - Coags |
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Post-Op:
- Similar to thyroidectomy (dressing, emergency equip., etc.) - Check Ca levels - Monitor for s/s hypoparathyroidism - Voice (r/t laryngeal edema) - hoarseness - May need lifelong treatment |
Cheatography n. The art of mapping complex subjects into clear, instantly navigable reference guides.