T3-Thyroid Medications-MJ Flashcards
Discuss the patho of hypothyroidism.
- Hypothalamus produces TRH
- TRH stimulates anterior pituitary to produce TSH
- TSH stimulates thyroid to produce T3 and T4
- Negative feedback occurs when T3 and T4 are being made to tell the ant. pit. to STOP releasing TSH
If thyroid levels are too low, then ___ should rise to stimulate the thyroid to make more.
TSH
What does the thyroid hormone do?
Regulates metabolism
Growth and development (bones, brain, etc)
What are the two types of HYPOthyroidism?
Cretinism
Myxedema
What age group is cretinism in?
Neonates and infants
What are the characteristics of cretinism?
Mental retardation Short stature and skeletal abnormalities Coarse facial features Enlarged tongue Umbilical hernia
Why would an neonate or infant have cretinism? (4 possible reasons)
- Maternal hypothyroidism (1st trimester)
- Thyroid agenesis
- Dyshormonogenic
- Iodine deficiency
Cretinism: Why does maternal hypothyroidism effect an infant?
This must be treated VERY early. If a mother has this and doesn’t realize she does then it can cause permanent neuropsychologic effects in the child. This is because during the first trimester the baby cannot produce its own thyroid hormone.
Cretinism: What is thyroid agenesis?
The baby is born without a thyroid
What age group is myxedema in?
Older children and adults
What are the clinical features of myxedema? (11)
CC-FH-MWMW-SOB-SOB
Cold intolerance Constipation Fatigue Hypercholesterolemia Myxedema Weight gain (despite normal appetite) Muscle Weakness Shortness of breath Slowing of mental activity Oligomenorrhea Bradycardia
What are the causes of myxedema (3)?
- Iodine deficiency
- Hashimoto thyroiditis (immune system attacks thyroid)
- Lithium
What is the thyroid function test that is useful for diagnosing HYPERthyroidism?
Total T3
What is the thyroid function test that is useful for diagnosing HYPOthyroidism?
TSH (highly sensitive)
What is the drug of choice that can be given for all types of thyroidism?
Levothyroxine
Levothyroxine is synthetic T4. What does that mean?
It is synthetic and it can be converted into T3 (the active form)
What does levothyroxine do to the metabolism?
Revs it up–pushes on the gas pedals
What are the adverse effects of levothyroxine?
Insomnia Anxiety Weight loss Sweating Increased HR and BP
What are some of the problems of levothyroxine?
Many food and drug interactions
MUST TAKE ON AN EMPTY STOMACH
Narrow therapeutic index
There is generic controversy with levothyroxine. What does that mean?
The active ingredient is the same in both the generic and the trade. The only difference is the “packaging” of the drug. Switching from the trade to generic (or generic to trade) matters since it is a narrow therapeutic index drug!
Is thyroid storm associated with hypothyroidism or hyperthyroidism?
HYPERthyroidism…but this can happen with overdose of a patient who has hypothyroidism and is taking a drug.
Either way, it is the cause of too much thyroid levels!!
What are the 5 early signs of a thyroid storm?
STORM Severe tachycardia Tremor Over 40.5 degree temp Restlessness Mean (Agitation)
If the early signs of a thyroid storm are not treated, late signs start to happen. What are the 3 late signs?
Unconsciousness, coma
Hypotension
Heart failure
How is a thyroid storm treated?
Aggressive care
Potassium iodide
Methimazole
Beta blocker
Thyroid storm treatment: What will potassium iodide do?
Stops release of thyroid hormone
Thyroid storm treatment: What does methimazole do?
Stops synthesis of new additional thyroid
Thyroid storm: What does beta blocker do?
Slows down the tachycardia
