Ch 40: Thyroid Disorders

Question 1

hypothyroidism pathophys

Answer 1

deficiency in T4 (T3 is more active but shorter half life) and elevation of TSH

Question 2

hyperthyroidism pathophys

Answer 2

excess of T4 and decrease of TSH

Question 3

hypothyroidism sx

Answer 3

fatigue, wt gain, cold sens, dry skin, myalgias, voice changes, constipation, goiter, depression, bradycardia

Question 4

hypothyroidism dx

Answer 4

low free T4 (normal is 0.9-2.3 ng/dl). high TSH (normal is 0.3-3 mIU/L)

Question 5

hypothyroidism in preg

Answer 5

IV levothyroxine is safe in preg, may need 30-50% inc throughout the course of preg and several months afterwards (monitor T4 and TSH levels)

Question 6

dessicated thyroid

Answer 6

T3 and T4. armour thyroid. “natural” dosed in grains

Question 7

liothyronine

Answer 7

T3. cytomel or triostat. shorter half life than T4, more fluctuations.

Question 8

levothyroxine

Answer 8

T4. synthroid. drug of choice for hypothyroidism d/t chem stability, QD dosing, low cost, lack of antigenicity, more uniform potency. IV to PO is 0.75:1.

Question 9

BBW thyroid supplements

Answer 9

ineffective and potentially toxic when used for t of obesity or for wt reduction, espec in euthyroid pts

Question 10

levothyroxine dosing

Answer 10

full replacement dose is 1.6 mcg/kg/d IBW. if known CAD, start with 12.5-25 mcg QD

Question 11

hypothyroidism monitoring

Answer 11

check TSH and clinical sx q4-6wks until stable

Question 12

levothyroxine tablet colors

Answer 12

Orangutans Will Vomit On You Right Before They Become Large Proud Giants. 25 mcg orange. 50 mcg white (no dye). 75 mcg violet. 88 mcg olive. 100 mcg yellow. 112 mcg rose. 125 mcg brown. 137 mcg turquoise. 150 mcg blue. 175 mcg lilac. 200 mcg pink. 300 mcg green.

Question 13

thyroid supplement counseling

Answer 13

take with water 60 min before breakfast or at bedtime at least 3 h after your last meal OES. separate from meds.

Question 14

hashimoto’s disease

Answer 14

autoimmune disease where Abs attack the thyroid to cause hypothyroidism

Question 15

graves disease

Answer 15

autoimmune disease where thyroid produces too much T4 to cause hyperthyroidism

Question 16

hyperthyroidism sx

Answer 16

heat intolerance, wt loss, agitation, tachycardia, diarrhea, insomnia, exophthalmos (protrusion of the eyeballs), absent mentstual periods

Question 17

drugs that can cause hyperthyroidism

Answer 17

iodine, amiodarone, interferons

Question 18

thyroid storm tx

Answer 18

lifethreatening med emergency. antithyroid (PTU preferred over methimazole), inorganic iodide (SSKI or lugols soln), BB for tachycardia sx, systemic steroid, aggressive supportive tx (apap and cooling blankets, etc)

Question 19

thyroid storm sx

Answer 19

fever >103, tachycardia, tachypnea, dehydration, profuse sweating, agitation, delirium, psychosis, coma

Question 20

propylthiouracil (PTU)

Answer 20

thionamide. BBW for severe liver injury. preferred in 1st trimester of preg. ADR of GI upset (take with food) and hepatitis, agranulocytosis (rate). takes 1-3 mo at higher doses to control sx then reduced to prevent hypothyroidism. inhibits synthesis of thyroid hormones by blocking the oxidation of iodine in thyroid gland, also inhibits peripheral conversion from T4 to T3.

Question 21

methimazole

Answer 21

Tapazole. thionamide. no BBW. preferred in 2nd and 3rd trimester (switch from PTU). ADR of GI upset (take with food) and hepatitis, agranulocytosis (rate). takes 1-3 mo at higher doses to control sx then reduced to prevent hypothyroidism. inhibits synthesis of thyroid hormones by blocking the oxidation of iodine in thyroid gland.

Question 22

Lugol’s soln and SSKI - Iodides

Answer 22

temporarily inhibit secretion of thyroid hormones.