EXAM- Thyroid Cases Flashcards
Nancy has been feeling “unwell” lately. You see her in the office and send her for labs. Her TSH comes back at 11 and her fT4 is 4. Unfortunately the lab forgot to indicate if these values are low or high. What resource can you refer to? What will Nancy be diagnosed with?
Rx files p. 57
Hypothyroidism
What is your general approach to therapy? How will this help Nancy? Are lifestyle modifications an adequate first line treatment?
No, lifestyle modifications are not adequate. Nancy needs LEVOTHYROXINE (T4). The goal is to increase free thyroid hormone to reduce symptoms and TSH.
Recall- T4 is the only thing we can prescribe for hypothyroid as NPs (per Susan)
What is the half life of levothyroxine? Why is this beneficial?
-T1/2 is 7 days.
-Allows for stable level of prohormone in the blood
-can be dosed once a day
-Patient will be ok (not symptomatic) if they miss a dose
What will you prescribe for Nancy? Her weight is 50kg. What teaching will you provide?
Synthroid 88mcg once daily, take by mouth on an empty stomach in the morning 30min- 1 hour before breakfast.
Take at the same time every day. We will recheck your thyroid levels in 4-8 weeks. Once your thyroid levels are stabilized we will check your TSH every 6-12 months.
AE often due to overtreatment- palpitations, inc HR, tremors, anxiety, diarrhea, can exacc existing CVD. Possible dec BMD.
CI in acute MI and adrenal insufficiency
Many drug interactions are possible- ensure your prescriber knows you are on this medication
Levothyroxine 1.7mcg/kg/ day x 50kg= 85mcg/ day
Rx files p. 58
You recheck Nancy’s TFTs in 6 weeks and her TSH is 0.05 and TH is 25! She says she has been taking 2 pills a day as they are helping her lose weight. What is going on? What should you do?
Hyperthyroid!
Now probably has anxiety, restlessness, tremors, palpitations, systolic HTN, heat intolerance, diarrhea, etc.
Patient teaching is key.
If you have a patient taking synthroid as prescribed and they were found to have low tsh/ high th, you would need to decrease their dose.
Joe is a 35yo cis M who presents with anxiety, palpitations, sleep disturbance, racing thoughts, and weight loss. You send him for blood work. His TSH is <0.1 and his TH is 35. What would you diagnose him with? What are your next steps for blood work?
Thyrotoxicosis (hyperthyroidism)
Check TSH receptor autoantibodies (Graves if positive; requires radionuclide uptake scan if negative for possible toxic nodule).
What possible drug classes can be used for hyperthyroidism? Which one can you (as an NP) prescribe?
Which one is first line for treatment of thyrotoxicosis?
Thionamides (MMI and PTU) (I think this is the only we can rx as NPs? THIONAMIDES ARE FIRST LINE TX FOR THYROTOXICOSIS * EXAM Q*
Iodide
Adrenergic blockers
Radioactive iodide
Turns out, Joe has Grave’s disease! Write him a prescription and some teaching
Methimazole 5mg po daily (rx files p. 58)
Clinical improvement in days
Joe is a cis M- if otherwise, requires teaching re pregnancy (MMI caution in 1st trimester due to craniofacial malformations- consider PTU first trimester, MMI thereafter).
Serious AE- agranulocytosis, neutropenia (s&s infection), cholestatic jaundice, ? vasculitis,
Minor AE- skin rash, arthralgias, abnormal taste/ smell.
DI- warfarin, dig, others
Monitoring: recheck TSH in 4-6 wks, CBC and LFT baseline and 1 wk.
Joe is actually a medical student and argues that according to his resource, because his fT4 is 1.5- 2x higher than normal, he should be on 20mg MMI instead of 5mg.
How do you explain your choice to start with a low dose?
MMI (/thionamides) interrupt thyroid hormone synthesis, thus lowering Joe’s level of TH. If we start with a high dose of MMI, we may be overtreating Joe, and he may experience hypothyroid symptoms (feeling low, tired, slow, brain fog). If Joe’s symptoms are manageable, it is better to start with a low dose of MMI and titrate up as needed (based on his TSH and sx). A large initial dose may also cause cause GI upset.
Also, Susan told us to start at the lowest dose “we dont want to overshoot and make hypothyroid as fairly stable, we are being cautious” “people don’t like feeling low”.
Joe wants to know about other medication options he has. He asks you to tell him about iodide.
Used for thyrotoxicosis; first form of drug therapy for graves
MOA: blocks TH release, inhibits TH biosynthesis, decreases size and vascularity of the gland. Inhibitory effect provides symptom improvement in 2-7 days BUT TH remains stored in the gland. Eventually it escapes and sx return. Can be used as adjunt while awaiting therapy.
Joe thinks this makes sense. He now asks you to explain radioactive iodide to him.
rx by endocrinologist
may lead to long term problems for pt
disrupts hormone synthesis by incorporating into gland and TH
Follicles that take up RAI> cellular necrosis> destruction of gland.
Hypothyroidism commonly occurs.
Joe agrees with you that MMI is the best drug for him. He asks you for a prescription for ativan because his symptoms feel unmanageable- he cant stand the feeling of his heart racing and he is so anxious!!!! He also believes it will help with his sleep. What do you do?
No BZDs for you Joe! Adrenergic blockers (i.e., propanolol) will actually work way better to control your symptoms resulting from high levels of TH. They also help block the conversion of t4> t3 (active th) :)
Joe is leaving your office, but on the way out says “wow, you were so proficient! What resources do you use to help you figure out thyroid testing and prescribing?”. What do you answer?
I personally used rx files and the bc guidlines “thyroid fcn testing…” susan posted on brightspace.
