ch 49 highlights Flashcards
in adults mild thyroid hormone deficiency is called
hypothyroidism
Severe thyroid deficiency is called
myxedema
When hypothyroidism occurs in infants its called
congenital hypothyroidism
if someone is pale, puffy, expressionless face with cold and dry skin. The hair is brittle and hair loss occurs. Heart rate and temp are lowered. Pt complains of lethargy, fatigue and intolerance to cold. Mentation may be impaired. What disease process do these symptoms most correlate to?
Hypothyroidism
maternal hypothyroidism can result in
permanent neurophysiological deficits in the child
At what trimester does the fetus have a thyroid gland that is fully functional and able to supply his/her own hormones
2 nd trimester
a pt with hypothyroid becomes pregnant
dosage requirements usually increase often by as much as 50% . The need for increased dosage begins at 4-8 weeks gestation and levels off at approximately week 16 then remains steady
In children with congenital hypothyroidism therapy should continue for
3 years then d/c for 4 weeks. Blood work to see if the TSH rises.
the more TSH the more
hypothyroid the pt is
the less TSH the less
hypothyroid the pt is
which form of hyperthyroidism has exophthalmos
Graves
Which form of hyperthyroidism does not have exopthalmos
Plummer Disease
Graves disease is most common in what gender
women
nervousness, insomnia, rapid speech, weakened muscles, increased body temp, intolerance to heat and skin that is warm and moist, increased appetite, weight loss
thyrotoxicosis
Treatment for Graves disease
1) Surgical removal of thyroid tissue
2) destruction of thyroid tissue with radioactive iodine
3) suppression of thyroid hormone synthesis with an anti-thyroid drug (methimazole or propyolthiouracil)
radiation is preferred treatment for adults
antithyroid drugs is preferred for younger ptatients
improvement of exophthalmos
will not improve with lowered thyroid levels
if severe, it can be treated with surgery and radiation
symptoms profound hyperthermia (105 or higher) severe tachycardia restlessness agitation tremor
unconsciousness coma hypotension heart failure may ensue
thyrotoxic crisis (thyroid storm)
what is given for thyroid storm
high doses of potassium iodine solution to suppress the hormone synthesis
B blocker is given to reduce heart rate additional measures include sedation cooling glucocorticoids IV fluids
first line for hypothyroid
Levothyroxine (Synthroid) - used in all types and for all causes of hypothyroid
what time of day should synthroid be taken?
30 min before breakfast on an empty stomach
overdose on synthroid
causes thyrotoxicosis - tachycardia angina tremor nervousness insomnia hyperthermia heat intolerance sweating
chronic overdose - accelerated bone loss
increased risk of a-fib (esp older adults)
loss of bone increases r/o fractures
drugs that reduce levothyroxine (synthroid) absorbtion
H2 receptor blockers (cimetidine (tagamet)) PPI (Prevacid) Sulcralfate (Carafate) Cholestyramine (Questran) Colestipol (Colestid) Aluminum containing antacids (maalox, mylanta) Calcium supplements (Tums, Os-cal) Iron supplements (ferrous sulfate) mag salts Orlistat (Xenical)
separate administration of synthroid and these drugs by 4 hours
drugs that accelerate levothyroxine metabolism
phenytoin (Dilantin) Carbamazepine (Tegretol, Carbatrol) Rifampin (Rifadin) Sertraline (zoloft) phenobarbitol
if a pt on warfarin begins levothyroxine
synthroid accelerates the degradation of vit k-dependent clotting factors. Effects of Warfarin are enhanced and dosage of warfarin may need to be reduced
drug interaction for Synthroid
Catecholamines (dopamine, norepinephrine, epinephrine) - Thyroid hormones increase cardiac responsiveness to catecholamines, which increases the risk for catecholamine-induced dysrhythmias
Synthroid can increase requirements for
insulin and digoxin. Doses may need to be increased
are Synthroid products interchangeable?
no, if you have to change manufacturers, levels will need to be monitored closer
what is given for myxedema coma
IV synthroid
when should you recheck labs after initiating Synthroid therapy
Check 4-6 weeks, then 6 mos -1 year after stabilzed
what drug class
methimazole
propylthiouracil (PTU)
Anti-thyroid drugs: Thionamides
What thionamide is appreved for pregnant or breastfeeding and for patients who are in thyrotoxic crisis
PTU - place pt on PTU for first trimester then switch them back to methimazole
what drug is first line for this class for hypothyroid
Methimazole (Tapazole)
what is the most dangerous toxicity for Methimazole
Agranulocytosis
what is the first symptoms of agranulocytosis
This develops in the first 2 months of therapy
Sore throat and fever may be the earliest indication
Treatment for Agranulocytosis
D/c methimazole
usually reverses on its own
Filgrastim (Neupogen) may accelerate recovery
Radioactive Iodine advantages for treating hyperthyroidism
low cost
patients spared risk of thyroid surgery
death from treatment is extremely rare
no tissue other than thyroid is injured
drawbacks to Iodine therapy for treating hyperthyroidism
effect of treatment is delayed (takes several months to become maximal)
Associated with delayed hypothyroidism from excessive dosing and occurs in up to 90% of pts within the first year after Iodine exposure
Iodine therapy for hyperthyroidism is indicated for
Adults
slight risk of cancer when given to young patients
what iodine is given to hyperthyroid individuals to suppress thyroid function in preparation for thyroidectomy
Nonradioactive Iodine : Lugol solution aka strong iodine solution
Hyperthyroid while prepping for surgery
give methimazole to reduce plasma levels
strong iodine solution (Lugol) along with PTU for the last 10 days before surgery
Lugol Solution (Strong iodine solution) is also used for
thyrotoxic crisis
hypothyroidism in children is called
Cretinism
What is needed for the diagnosis of hyperthyroidism/hypothyroidism
TSH
Methimazole is safe in pregnancy when
2nd and 3 rd trimester
signs of synthroid tox
insomnia, tremors, tachycardia
what med do you give for thyroid storm
PTU
Iodine is indicated for
greater than 30 years old and not responding to other therapies
