final treatment overviews for thyroid and osteoporosis

Question 1

Levothyroxine Dosing

Initial Dosing:
1. otherwise healthy <65y.o:

2. otherwise healthy >/= 65 y.o:
3. known CAD:
4. subclinical hypothyroidism:

dosing changes

Answer 1

Dosing

Initial Dosing: BASED ON IBW, NOT ACTUAL

1. otherwise healthy <65y.o: 1.6 mcg/kg/day
2. otherwise healthy >/= 65 y.o: 50 mcg/ day
3. known CAD: 12.5-25 mcg/ day
4. subclinical hypothyroidism: unless compelling argument, avoid. (FOR PURPOSES OF THIS CLASS ONLY)

dosing changes

5. Pregnancy: 30% increase dose suggested; changes as soon as 5 weeks gestation.
6. severely obese (BMI>40 kg/m^2) may require higher replacement doses
7. Autoimmune gastritis, H. Pylori gastritis may require higher replacement doses due to increased acid production, drug break down, and decreased bioavailability.

Question 2

Hypothyroidism Treatment TimeLine

what to do if switching between LT4 preparations

Answer 2

Treatment TimeLine

1. start with appropriate initial LT4 dose for situation
2. check TSH in 4-6 weeks
   a. if TSH not WNL (0.5- 3.5-4 mIU/L): titrate dose up or down by 12.5-25 mcg/day. recheck in 4-6 weeks
   b. if TSH is WNL (0.5- 3.5-4 mIU/L): check TSH again in 4-6 months, then at least yearly or if reason to suspect absorption or metabolism has changed (new drug added, chronic disease, weight change, pregnancy)

Switching Between LT4 Preperations

1. obtain new labs after any switch
2. avoid switching if possible

Question 3

levothyroxine Pearls:

includes counseling: how to take it?
timing:

Answer 3

Pearls:

1. drug of choice for primary hypothyroidism
2. decreased risk of cardiac and metabolic diseases
3. counseling:
   a. take with H2O only and no other meds
   b. timing: take 60 minutes before breakfast OR at least 3 hours after evening meal
   c. remain consistent
   d. if miss a dose, take as soon as remember. if remember next day, patient can actually take 2 doses ??
   e. this is a lifelong therapy
   f. takes up to 6 weeks to see effect

Question 4

Thioamide Dosing

1. Typical MMI doses based off of what levels?

startin doses:

Maintenance dose:

Answer 4

Thioamide Dosing

1. Typical MMI doses canoe based on FT4

startin doses:
1-1.5x ULN: 5-10 mg/ day (usually qd)
1.5-2x ULN: 10-20 mg/ day (can be QD or BID)
2-3x ULN: 30-40 mg/day (best BID)

Maintenance dose: 30%-50% reduction from initial dose (taper down)

Question 5

Thioamide treatment algorithm

Answer 5

Thioamide treatment algorithm

1. consider abc liver panel to establish baseline values
2. start MMI (dose based on FT4 level)
3. check FT4, T3 in 2-6 weeks (more often if more sever)
   a. if patient is NOT euthryroid: continue therapy and check FT4, T3 in 2-6 weeks
   b. if pt. is euthyroid: taper dose down by 30-50% over a few weeks ad repeat thyroid panel (including TSH) in 4-6 weeks
4. After tapering down dose
   a. if patient is NOT euthyroid: increase dose slightly, repeat thyroid panel in 4-6 weeks
   b. if patient is euthyroid: continue therapy 12-18 months; monitor thyroid labs q 2-3 months
5. consider stopping MMI if TSH and TRAb levels are normal

Question 6

RAI pearls

Answer 6

Pearls:
1. counseling
a. avoid high-iodine foods before treatment ( due to Wolff-Chaikoff effect: thyroid rejects the large quantities of iodine and therefor preventing the thyroid from producing large quantities of thyroid hormone). if excess iodine taken before radioactive thyroid treatment, body all prevent radioactive iodine from getting into the thyroid.
b. instructions for outpatient treatment:
I. no contact with kids for 5 days
II. no contact with pregnant women: 10 days
III. no more than 2 hours of contact at a time
IV. bathroom etiquette-> wipe sprinkles of pee because it is excreted in urine
V. avoid bodily fluid contact )4 days. no sharing

Question 7

RAI treatment timeline

Answer 7

RAI treatment timeline

1. at dx, pt can be given propranolol for symptom control if necessary
2. more severe cases can start MMI to minimize thyroid hormone in thyroid before RAI to prevent big release of thyroid hormone. needs to be stopped 3-7 days before RAI dose
3. if female or child bearing potential, give pregnancy test
4. RAI therapy. single dose . 10-15 mCi
5. if patient had mild active graves opthalmopathy, give steroid (prednisone 0.4-0.4 mg/kg/day 1-3 days after RAI dose.
6. 3-7 days after RAI dose, add MMI as needed to decrease complications of release of thyroid hormone from RAI
7. after a few weeks of MMI, can taper off and d/c completely
8. after 1 month post RAI, can taper propranolol and steroid if being used
9. after 3 months, should be completely done with all of the drugs
10. if RAI successful (patient hypothyroid) start IBW- based replacement dosing with levothyroxine. monitor and adjust as in hypothyroidism
11. if hyperthyroidism persists after 6 months, guidelines suggest another round of RAI therapy

Question 8

Thyroidectomy

Prep

complications

post surgery

Answer 8

Thyroidectomy

Prep
1. get patient euthyroid and stable before surgery to avoid thyroid storm
a. start MMI 6-8 weeks before surgery. if they get too low, can give lt4 AS NEEDED
B. Start iodide 10-14 days before surgery. decreases thyroid vascularity and decreases blood loss
c. start beta blocker 7-10 days before surgery
d. consider normalizing calcium and vitamin. d since thyroid surgery can sometimes effect parathyroid gland

complications

1. transient or permanent hypocalcemia (<2%)
2. hyperthyroidism can persists if a sub thyroidectomy (up to 8%)
3. vocal cord abnormalities (<5%) (permanent laryngeal nerve injury <1%)

post surgery

1. obtain serum calcium, intact PTH levels before discharge. pt may need calcium/calcitriol supplementation
2. wean beta blocker
3. stop MMI
4. start levothyroxine at full IBW replacement dosing (unless elderly)
5. obtain TSH in 6-8 weeks

Question 9

what factors are included in the WHO FRAX score

11 of them

Answer 9

age, gender, prior op fracture, femoral neck BMD, low BMI, oral glucocorticoids (5 mg or more of prednisone or equivalent for 3 months or more, RA, secondary OP, parental hx of hip fracture, current smoking, alcohol intake of 3 or more drinks/day

Question 10

Interpeting T-scores

Answer 10

Interpeting T-scores
normal: -1.0 and above
low bone mass(osteopenia): between -1.0 and -2.5
osteoporosis: at or below -2.5
severe or established osteoporosis: at or below -2.5 with one or more fractures

Question 11

OP treatment regimen if never been treated

Answer 11

1st line. biophosphanates: alendronate
risendronate

if those done work use ibandronate or raloxifene

assess yearly

Question 12

OP treatment if had before

Answer 12

1st: denosumab, romosumab, teriparatide, abaloparate

2nd line: alendronate, risendronate

Question 13

calcium supplementation

formulations:

ADverse effects:

increased risk for:

DDI:

counseling for each formulation

Answer 13

c. supplements may increase risk of MI and stroke, cause kidney stones, AE like bloating, constipation, gas, acute distress.
d. H2RA and PPI decrease absorption of calcium carbonate. calcium supplements decrease absorption of levothyroxine, quinolone, tetracycline ABX. counsel pt on adequate timing of medication administration.
d. serum calcium not reflective of calcium intake
e. calcium supplementation formulations
1. Calcium carbonate
a. acid dependent: take with food
b. H2-RA and PPIs will decrease absorption of calcium carbonate because needs acid
2. Calcium citrate
a. take with or without food
f. can also be used as adjunct to osteoporosis therapy, or in pts who cannot tolerate osteoporosis therapy