Thyroid & Adrenal

Question 1

T3

Answer 1

Triiodothyronine - most active and more potent; shorter t1/2, shorter duration of action

Question 2

T4

Answer 2

thyroxine - more dominant circulating form; may be converted to T4 in peripheral tissues; longer T1/2.

Question 3

T3/T4 actions

Answer 3

Stimulation of energy use, stimulation of heart, promotion of growth & development

Question 4

Signs & symptoms of Hypothyroidism

Answer 4

Cold intolerance, weakness, stiffness, lethargy, fatigue; Dry skin, course hair, weight gain, constipation, slowed & hoarse speech, bradycardia, periorbital puffiness, slow DTRs Pediatrics: growth retardation

Question 5

Drug of choice for Hypothyroidism

Answer 5

Levothyroxine (Synthroid ®, Levothyroid ®, L-thyroxine)

Question 6

Adverse effects of preferred Hypothyroidism Drug

Answer 6

Nervousness, palpitations, tachycardia, heat intolerance, weight loss; With excessive doses > HF, angina, MI, Decrease Bone mineral density

Question 7

Myxedema Coma

Answer 7

Emergency hypothyroid condition: Spontaneous onset or precipitated by cold exposure, infection, analgesics, sedative drug use, respiratory or other severe illnesses

Question 8

Signs & symptoms of Myedema Coma

Answer 8

Coma, seizures, hypotension, hypoventilation

Question 9

Treatment for Myedema Coma

Answer 9

IV thyroid hormone (levothyroxine), steroid (cortisone), mechanical ventilation

Question 10

PTU

Answer 10

Propylthiouracil - Block thyroid hormone synthesis by inhibiting peroxidase enzyme system of the thyroid gland; Also inhibits peripheral T4>T3

Question 11

PTU - place in pregnancy

Answer 11

Preferred in pregnancy for hyperthyroidism because less drug crosses the placenta

Question 12

RAI

Answer 12

Radioactive Iodide - Sodium Iodide 131 - Concentrates in thyroid & disrupts thyroid hormone synthesis by incorporating into thyroid hormones & thyroglobulin (given as an oral liquid); follicles that uptake RAI develop necrosis & fibrosis of interstitial t

Question 13

RAI - place in pregnancy

Answer 13

Contraindication: Pregnancy

Question 14

Thyroid storm

Answer 14

MEDICAL EMERGENCY - Extreme manifestation of hyperthyroidism

Question 15

S/SX of Thyroid Storm

Answer 15

High fever, dehydration, arrhythmias, cardiac failure, coma

Question 16

Thyroid storm treatment

Answer 16

Beta Blockers: Control of sympathetic stimulation; also weak antithyroid effects (inhibition of peripheral conversion) IV fluids PTU: given before iodides (initially iodides may cause the formation of more thyroid hormone, PTU blocks this reaction) Iodide

Question 17

Actions of Glucorticoids

Answer 17

Metabolism actions and resistance to stress; Alter blood cell levels in plasma; Anti-inflammatory action; Affect other components of the endocrine system as well as other systems

Question 18

Use of Adrenal Corticosteriods

Answer 18

Replacement Therapy; Relief of Inflammation; Treatment of allergies; Acceleration of lung maturation

Question 19

Adverse effects of Adrenal Corticosteroids

Answer 19

CNS (Insomnia, psychosis); GI (Increaseappetite, IncreasePUD); Endocrine/metabolic (Hirsutism; Hyperglycemia; HPA suppression); Neuromuscular (Osteoporosis; muscle wasting); Ophthalmic (cataracts; glaucoma); CV (HTN); Other (edema, acne)

Question 20

Consequences of HPA suppression

Answer 20

Acute adrenal insufficiency (possibly fatal) Usually occurs with corticosteroid therapy > 2 weeks; taper off corticosteroid

Question 21

Use of Mineralcorticoids

Answer 21

Help regulate body’s fluid and electrolyte status (aldosterone)

Question 22

Action of Mineralcorticoids

Answer 22

Aldosterone causes NA+/H2O retention and K+ loss; Short t ½; Important for blood volume and blood pressure regulation

Question 23

Prednisone

Answer 23

Prednisone preferred corticosteroid during pregnancy