Term
| bromine, fluorine, lithium |
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Definition
| drugs that block iodide transport into thyroid |
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Term
| methimazole, propylthiouracil, sulfonylureas |
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Definition
| drugs that impairs organification & coupling of thyroid hormones |
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Term
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Definition
| drugs that inhibits thyroid hormone secretion |
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Term
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Definition
DIT + DIT;
100% produced in thyroid gland;
less active than counterpart;
long plasma half-life (7 days);
99.96% protein bound |
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Term
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Definition
DIT + MIT;
20% produced in thyroid gland;
4x more potent than counterpart; |
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Term
| propylthiouracil, amiodarone, propranolol, dexamethasone |
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Definition
| drugs that regulate deiodination of T4 to T3 |
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Term
| Thyroid Stimulating Hormone (TSH) Test |
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Definition
0.5 - 4.7 mIU/L;
INCREASED --> dx primary hypOthyroidism
DECREASED --> dx hypERthyroidism |
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Term
| Free Thyroxine (FT4) Test |
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Definition
0.8 - 2.7 ng/dL;
DECREASED --> hypOthyroidism;
INCREASED --> hypERthyroidism; |
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Term
| Total Triiodothyronine (TT3) Test |
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Definition
60-181 ng/dL;
Confirms Dx of HypERthyroid Disorder;
Normal levels in additon to normal FT4 & low TSH --> subclinical hypERthyroidism;
If low TSH --> normal FT4 --> raised levels in this test --> hypERthyroidism |
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Term
| American Thyroid Association (ATA) Screening Recommendations |
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Definition
begin at age 35 and every 5 yrs after;
ALL newborn children are legislatively mandated to be tested for hypOthryoidism |
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Term
| HypERthyroidism (Graves' Dx) |
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Definition
any state characterized by thyroid hormone excess (T4, T3, or both);
Ex: Graves' Dx, Thyrotoxicosis facitia, Amiodarone; |
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Term
| Clinical Presentation of HypERthyroidism |
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Definition
S: fine hair, warm moist skin, ophthalmopathy (GRAVES ONLY), thyromegaly, tachycardia, tremor, pretibial myxedema (GRAVES ONLY), exophthalmos;
Sx: nervousness, anxiety, palpitations, emotional lability, easy fatigability, weight loss, increased appetite, heat intolerance, increased bowel movements |
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Term
| Goals of Tx of HypERthyroidism |
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Definition
eliminate excess thyroid hormone;
minimize sx;
minimize long-term consequences; |
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Term
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Definition
tx of hypERthyroidism if:
- thyroid malignancy, large obstructive thyroid gland, severe opthalmopathy, lack of remission on antithyroid tx, refusal of radioactive iodine;
Pretreat w/ PTU (propylthiouracil) or methimazole until euthyroid OR iodides for 10-14 days before surgery to decrease gland vascularity;
Complications:
- hypothyroidism, hypoparathyroidism, vocal cord abnormalities, pain/scarring, persistence or recurrence of dx |
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Term
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Definition
relative potency: 1;
Preferred in pregnancy but still Cat. D;
Short half-life (1-2.5 hrs);
Protein bound, some urinary excretion;
Primary therapy for Graves' Dx;
First line in children, adolescents, and pregnancy;
Short-term therapy before radioiodine or surgery;
MoA:
- inhibits thyroid hormone biosynthesis & periperhal conversion of T4 to T3 |
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Term
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Definition
relative potency: 10;
Preg. Cat D;
Longer half-life (6-9 hrs);
NO protein binding, MINIMAL urinary excretion;
Primary therapy for Graves' dx;
First line in children & adolescents;
Short-term therapy before radioiodine tx or surgery; |
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Term
| Pt characteristics for Favorable Outcome with PTU or methimazole |
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Definition
older pts (>40 yrs);
low ratio of T4 to T3 (<20);
small goiter (<50 g);
short duration of dx (<6 months);
no previous hx of relapse w/ antithyroid drugs;
Duration of therapy 1-2 yrs or longer |
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Term
| Monitoring of Antithyroid Meds (PTU, methimazole) |
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Definition
TFTs at 4-6 wks until euthyroid state achieved;
Reduce dose at monthly intervals to maintain thyroid fcn or euthyroidism;
Continue antithyroid drug 1-2 yrs w/ goal to induce long-term remission;
Follow-up for relapse at 6-12 month intervals; |
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Term
| Alternative Therapy after Relapse from Antithyroid meds |
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Definition
| If relapse occurs after initial tx w/ PTU or methimazole, RADIOIODINE is PREFERRED to 2nd course of antithyroid meds |
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Term
| ADRs of Antithyroid Meds (PTU or methimazole) |
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Definition
Minor: GI upset, cutaneous rxns (skin rash, urticaria, pruritus), benign transient leucopenia;
Serious:
- hepatotoxicity - occurs w/in 1st 3 months, elevated LFTs, hepatitis, cholestatic jaundice;
- agranulocytosis - occurs in 0.3% of pts, develops within 1st 3 months, abrupt in nature, fever, malaise, sore throat, ANC < 1,000; |
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Term
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Definition
beta- & gamma-emitter that concentrates in thyroid gland w/ half-life of 8 days, cells develop abnormalities & necrosis;
Uses:
- 1st line tx of Graves' dx;
- tx of Graves' AFTER relapse w/ long-term antithyroid meds;
- tx of Graves' if major ADRs to antithyroid meds;
C/I: pregnancy, lactation;
Precautions: children & adolescents, pts w/ opthalmopathy;
Dosing: 5-15 mCi, single or repeat dose at 6 months to achieve euthyroidism; |
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Term
| Monitoring for Radioactive Iodine (RAI) |
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Definition
thyroid fcn test at 4-6 wks;
Use free thyroid hormones (FT4);
Most pts achieve euthyroid state within 6 months;
Most/all become hypothyroid --> life-long thyroid replacement |
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Term
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Definition
| transient thyroiditis, HYPOTHYROIDISM, thyroidal tenderness, dysphagia |
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Term
| Patient Education after RAI |
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Definition
Follow all of these for at least 3-7 days after tx:
- do not kiss or exchange saliva;
- do not share food or utensils;
avoid close contact w/ infants, young children, & pregnant women;
- flush toilet twice after urinating & wash hands thoroughly, men should sit, not stand;
- refrain from sex;
- separate linens;
- wash towels apart;
- drink plenty of fluids;
- sleep alone; |
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Term
| Iodides - saturated soln of potassium iodide (SSKI) & Lugol's Soln |
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Definition
MoA: acutely blocks thyroid hormone release, decreases size & vascularity of gland;
Indications:
- preparation of pt w/ Graves' dx prior to surgery;
- quick reduction in hormone release in severely thyrotoxic pts;
ADRs: skin rashes, fever, rhinitis, conjunctivitis, "Iodinism" --> metallic taste, burning mouth & throat, sore teeth & gums, head cold, stomach upset, diarrhea; |
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Term
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Definition
| blocking of organic binding of IODINE & its incorporation into hormone by large doses of IODIDE; |
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Term
| Propranolol - beta-blockers |
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Definition
MoA: alleviates sx related to increased beta-adrenergic activity (anxiety, tremor, palpitations, heat intolerance);
- blocks conversion of T4 to T3;
Uses:
- adjunctive tx of Graves' dx, adjunctive tx of thyroid storm;
Dose: 20-40 mg QID & titrated to relieve S/Sx |
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Term
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Definition
defect located at thyroid gland;
Most common cause: Hashimoto's Dx - autoimmune disorder;
Iatrogenic - RAI, external radiation, surgery;
Iodine Deficiency - 3rd world countries, lack of substrate; |
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Term
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Definition
abnormality in anterior pituitary or hypothalamus;
Ex: pituitary dx (tumors, surgical removal, radiation), hypothalamic dx (cranial irradiation, trauma, infiltrative dx or neoplastic dx);
Medications - amiodarone, alpha-interferon, lithium, antithyroid drugs |
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Term
| Clinical Presentation of Hypothyroidism |
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Definition
Insidious onset, non-specific manifestations;
S: course skin/hair, thin brittle nails, thinning eyebrows, rough dry skin, hoarseness, slow speech, periorbital puffiness, bradycardia, nonpitting edema, delayed relaxation of reflexes, goiter;
Sx: fatigue, lethargy, depression, weight GAIN, CONSTIPATION, cold intolerance, decreased concentration, loss of ambition & energy, muscle cramps, myalgia, stiffness |
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Term
| Subclinical Hypothyroidism |
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Definition
elevated TSH, normal FT4 and T3;
Most are asymptomatic or subtle Sx;
Tx recommended w/ TSH >10 mIU/L |
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Term
| Goals of Tx for HYPOthyroidism |
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Definition
restore normal thyroid hormone conc;
provide symptomatic relief;
reverse biochemical abnormalities; |
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Term
| Natural Thyroid Hormone - thyroid USP (Armour Thyroid) |
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Definition
animal-derived products; nonphysiologic;
amount of T3 may be higher than that found in human gland; unpredictable hormone content & stability;
generics may not be bioequivalent;
Antigenic in some allergic or sensitive pts; |
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Term
| levothyroxine (Unithroid, Synthroid, Levoxyl) |
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Definition
synthetic T4;
GOLD STANDARD for tx of hypOthyroidism;
stable, predictable potency;
inexpensive & free of antigenicity;
PKs: eliminated by kidneys, long half-life (7 days);
Dose:
- 1.7 mcg/kg/day - IBW in obese pts;
- 1 mcg/kg/day in pts OVER 65;
Take as single dose 30-60 min before breakfast on EMPTY STOMACH;
- be consistent (delayed absorption w/ fiber, soy, bran);
ADRS: allergic rxn to dyes, cardiac consequences w/ excessive dose;
BBW: not for obesity/weight loss use; |
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Term
| Dosing Pts < 50 yrs WITHOUT known cardiac disease |
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Definition
1) Full replacement dose - use dosing nomogram;
2) 50 mcg daily; |
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Term
| Dosing Pts >50 yrs OR those w/ KNOWN cardiac Dx |
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Definition
1) 25 mcg daily;
2) 12.5 mcg daily with age + cardiac dx |
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Term
| Drugs that cause decrease in T4 absorption |
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Definition
| malabsorption syndromes, cholestyramine, aluminum hydroxide, ferrous sulfate, calcium carbonate, sucralfate, fiber supplements, soy |
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Term
| Drugs that cause increase in T4 clearance |
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Definition
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Term
| Dx states that increase thyroxine binding globulin (TBG) |
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Definition
| pregnancy, cirrhosis, estrogen therapy |
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Term
| Monitoring of Thyroid Levels w/ tx of Synthetic Thyroid |
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Definition
TSH and/or FT4 q6 wks;
Sx & labs q6 wks until euthyroid state achieved;
Every 6-12 months for pts stable on therapy |
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