Thyroid Disease
Affects metab., growth, development; temp. regulation, HR, RR (every cell, tissue, organ) |
Endocrine system = "duct system" |
How does it work? |
Negative feedback loop... - Hypothalamus releases TRH Pituitary releases TSH Thyroid releases T 3
& T 4
T 3
& T 4
maintain normal levels in blood Normal function maintained Normal levels "turn off" hypothalamus |
Hypothyroidism
Underactive thyroid; not enough T 3
and T 4
|
Primary: dec. thyroid tissue, dec. TH
Secondary: inadequate TSH production |
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 |
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 |
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 |
Pretibial myxedema (PM): r/t accumulations of mucopolysaccharides; reversible
Hashimoto's Disease
Most common cause of hypothyroidism |
Cause: immune system attacks thyroid
- Also: dec. iodine, tumor, overtreated |
Manifestations: dysphagia, enlarged thyroid |
Risk Factors: sex, age, heredity, another autoimmune disorder, radiation |
Complications: goiter, cardiac problems, mental health, myxedema, birth defects |
Myxedema Coma
A medical emergency; "severe" hypothyroidism (r/t untreated, stopping meds) |
Causes: acute illness, surgery (thyroid), chemo, narcotics, d/c replacement therapy |
Presentation:
- Coma
- Respiratory failure & hypotension
- Hypothermia
- Hyponatremia (r/t dec. glomerular fx)
- Hypoglycemia (r/t gluconeogenesis) |
Monitor:
- Labs & electrolyte imbalance(s)
- Resp. rate & heart rhythms |
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) |
Hyperthyroidism
Increased secretion of thyroid hormones |
Causes:
- Grave's disease (most common)
- Multiple thyroid nodules
- Toxic multinodular goiter
- Excessive thyroid replacement hormones
- Thyroiditis
- Too much iodine |
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 |
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 |
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 |
Propiothiouracil (PTU) - stops T 3
& T 4
; doesn't harm gland; can take in 1st trimester, but can cause liver failure
Tapazole (Methimazole) - causes anemia, safer
|
|
Grave's Disease
Autoimmune; most common cause of hyperthyroidism |
Cause: antibodies attach to TSH receptors inc. # and size of cells thyroid enlarges (goiter) overproduction of hormones |
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 |
Thyroid Storm (Thyrotoxic Crisis)
What is it? - Extreme exacerbation of hyperthyroidism |
Causes: illness, Grave's disease, meds that inc. TH, untreated/undiagnosed tumor |
Signs & Symptoms:
- Inc. HR & BP = severe cardiac problems
- Inc. temp = diaphoresis
- Resp. failure
- Anxiety or agitation |
Treatment:
- Interventions to counteract symptoms
- Block TH synthesis
- Control temp. NO ASA
- Meds to suppress immune system? |
Diagnostic Tests for Thyroid Problems
| |
HYPO |
HYPER |
|
|
|
|
|
|
TSH = 0.4-4 |
|
|
TSH Assay |
|
|
Thyroid Labs - T 3
, T 4
, TSH
TSH Assay - r/t central hypothyroidism
Thyroid Peroxidase (TPO) - enzyme in follicle cells important to hormone production; converts T 4
to T`3; (+) may indicate autoimmune, not definite for thyroid disease
Radioisotope Uptake Scan - evaluates size, areas of over- or under-activity
Thyroid Scan
Thyroid US - uses sound waves to image, characteristics (nodules, blood flow)
Fine Needle Aspiration (FNA) - malignant vs. benign
Thyroid Surgery
Total or subtotal thyroidectomy |
When?
- Large goiter, poor response to drugs
- Can't/won't take meds
- Malignancy |
Pre-Op:
- Meds: dec. hormone secretion,
beta-blocker, steroids to dec. immune system (w/ autoimmune dx)
- Control: HTN, dysrhythmias, tachycardia |
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 |
Complications: hemorrhage, resp. distress, parathyroid injury |
|
|
Hypoparathyroidism
Abnormally low levels of PTH |
Causes:
- Iatrogenic
- Idiopathic
- Hypomagnesemia (inhibits PTH secretion)
- Other: autoimmune |
Signs & Symptoms:
- P = paresthesias, positive Chvostek's & Trousseau's signs
- T = tetany (bronchospams, seizures, EKG)
- H = hypocalcemia & hyperphosphatemia |
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 |
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 |
Chvostek's sign: tap facial nerve, + when twitches (= dec. Ca)
Trousseau's sign: inflate BP cuff 20-30 mm Hg above normal for 3-5 min; + when involuntary arm movement
PTH inj. (Natpara) - last resort (inc. risk of osteosarcoma)
Calcium in Parathyroid Disease
Major controlling factor of PTH secretion |
Ca & PTH are directly related
- Increase in PTH = increase in Ca |
Affects kidneys (regulates P), bones, GI tract |
Hyperparathyroidism
Abnormally high levels of PTH |
Causes:
- Primary: hyperplasia, cancer growth
- Secondary: CKD (PTH overworked = inc. Ca absorbed), vitamin D deficiency |
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) |
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) |
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 |
Education:
- Medication compliance
- Monitor for s/s of hypocalcemia
- Diet
- Prevent complications: osteoporosis, traumatic fractures |
Diagostic Tests for Parathyroid Problems
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 |
Hypoparathyroidism:
- Decreased... Ca, Mg, PTH, vitamin D
- Increased... phosphate |
X-rays |
24-hour urine collection for calcium |
Parathyroidectomy
Total or subtotal |
Pre-Op:
- Get Ca in check
- Coags |
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 |
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