NR565 Final Study Guide
Be familiar with the interactive activities throughout course modules. You could see
variations of those same questions on your exams.
Week 5
Thyroid
o Diagnosis & Evaluation
What labs are used to diagnose?
TSH, total T4 and T3, free T4 and T3, also get LFTs and CBC
Timeframe for re-check of labs after starting levothyroxine
6-8 weeks after starting therapy. euthyroid 1 year
Signs and symptoms of hypo and hyperthyroidism
hypothyroidism: The face is pale, puffy, and expressionless. The
skin is cold and dry. The hair is brittle, and hair loss occurs. Heart
rate and temperature are lowered. The patient may complain of
lethargy, fatigue, and intolerance to cold.
hyperthyroidism: Graves’ disease and toxic nodular goiter (also
known as Plummer disease: Graves’ disease may cause
exophthalmos, whereas toxic nodular goiter does not. Heartbeat is
rapid and strong, and dysrhythmias and angina may develop. The
central nervous system is stimulated, resulting in nervousness,
insomnia, rapid thought flow, and rapid speech. Skeletal muscles
may weaken and atrophy. The metabolic rate is raised, resulting in
increased heat production, increased body temperature, intolerance
to heat, and skin that is warm and moist. Appetite is increased.
However, despite increased food consumption, weight loss occurs
if caloric intake fails to match the increase in metabolic rate.
Collectively, the previous signs and symptoms are referred to as
thyrotoxicosis. In addition to thyrotoxicosis, patients with Graves’
disease often present with exophthalmos
o Treatment
Treatment of thyroid storm
PTU (Propylthiouracil) is preferred treatment of thyroid
storm. High dose potassium iodine or strong iodine solution to
suppress thyroid hormone release, or methimazole to suppress
thyroid hormone synthesis, corticosteroids, beta-blockers-
reduce heart rate, and supportive measures are needed
(sedation, cooling, IV fluids).
Result of not treating hypothyroidism during pregnancy
, NR565 Final Study Guide
Permanent neurological defects, decreased IQ, large
protruding tongue, potbelly dwarfish stature, impaired
development of nervous system bone teeth and muscles.
Medication to treat symptoms of hyperthyroidism (notice this is treating
symptoms and not the hyperthyroidism itself)
Metoprolol can be used to treat tachycardia experienced with
hyperthyroidism.
Allopurinol is used in the management of gout.
Methylphenidate is a central nervous system stimulant
Drug/Food/Supplement interactions with levothyroxine
Absorption is reduced by:
o Histamine 2 receptor blockers (Cimetidine)
o PPI (Lansoprazole, omeprazole)
o Sucralfate (Carafate)
o Cholestyramine (Questran)
o Colestipol (Colestid)
o Aluminum containing antacids (Maalox, mylanta)
o Iron Supplements
o Calcium supplements (tums)
o Magnesium Salts
o Orlistat (Xenical)
o 4 Hrs between levothyroxine and the above meds is
recommended and food reduces absorption as well waitn
30-60 mins
Metabolism accelerated by: (INDUCERS)
o Phenytoin (Dilantin)
o Carbamazepine (Tegratol, Caratrol)
o Rifampin
o Sertraline
o Phenobarbital
o Patient taking these medications will need to have dose of
levothyroxine increased
Warfarin
o Levothyroxine accelerates the degradation of vitamin K-
dependent clotting factors
o May need to reduce the dose of warfarin
Catecholamines
o Increased cardiac responsiveness-at an increased risk of
catecholamine (norepinephrine,epinephrine, dopamine)-
induced dysrhythmias
Digoxin and Insulin