2. Hypothyroidism management
Prof. Ashraf Aminorroaya
Isfahan Endocrine and Metabolism Research Center,Isfahan University of Medical Sciences
Isfahan, Iran
21 April 2017

3. Case 1 (hypothyroidism management)
A 35 years old woman with fatigue, muscle cramp, firm goiter (2*Nl), positive TPOAb and TSH=40 mIU/L.
Questions:
The best treatment
Time of administration
Intervals of follow up
Target of treatment
Duration of therapy

4. Case 2 (hypothyroidism management)
A 75 years old man, known case of coronary artery disease and postablative hypothyroidism , with puffiness, dry hair and skin, constipation, TSH= 60 mIU/L.
Questions:
Dose of levothyroxine
Intervals of follow up
Target of treatment

5. Case 3 (hypothyroidism management)
A 30 years old woman, known case of hypothyroidism and TSH> 100 mIu/L was treated for 12 weeks with 100 µg/d of levothyroxine.
Now, she is, clinically, euthyroid. However, TSH level is still 35 mIu/L.
Question:
How do you treat the patient?

6. Case 4 (hypothyroidism management)
A well-controlled hypothyroid patient for many years on a stable dose of levothyroxine, now, has symptoms and sign of hypothyroidism and TSH=30 mIu/L.
Question:
What could be the cause?

7. Central hypothyroidism
known hypothalamic or pituitary disease
A mass lesion is present in the pituitary
When symptoms and signs of hypothyroidism are associated with other hormonal deficiencies

8. Treatment T4 : 1.6 mcg/kg /d, varying from 50 to ≥200 mcg/day
Older patients should be started on a lower dose (25 to 50 mcg daily)
Measure TSH after 6 weeks
Young: 0.4 and 2.5 mU/L
Old: age-adjusted upper limits of normal
Goal: No symptoms with NL TSH and to avoid overtreatment (iatrogenic thyrotoxicosis), especially in the elderly
THYROID
Volume 24, Number 12, 2014
American Thyroid Association

9. Prescribing brand-name levothyroxine preparations?
Yes
Switches between levothyroxine products could potentially result in variations in the administered dose and should generally be avoided for that reason
THYROID
Volume 24, Number 12, 2014
American Thyroid Association

10. Time of levothyroxine administration
Co-administration of food and levothyroxine impairs levothyroxine absorption
60 minutes before breakfast or at bedtime (3h or more after the evening meal) for optimal, consistent absorption
THYROID
Volume 24, Number 12, 2014
American Thyroid Association

11. Co-administration of medications and supplements with levothyroxine
Avoid with potentially interfering medications and supplements (e.g., calcium carbonate and ferrous sulfate)
A 4-hour separation is traditional, but untested.
THYROID
Volume 24, Number 12, 2014
American Thyroid Association

12. High dose levothyroxine requirement
Investigate gastrointestinal conditions:
Helicobacter pylori–related gastritis
Atrophic gastritis
Celiac disease
THYROID
Volume 24, Number 12, 2014
American Thyroid Association

13. Medications affect on T4 requirement by altered metabolism or binding to transport proteins
Estrogen
Androgens
Phenobarbital
Phenytoin
Carbamazepine
Rifampin
Sertraline
THYROID
Volume 24, Number 12, 2014
American Thyroid Association

15. Factors determine the levothyroxine starting dose
Patient’s weight
Lean body mass
Pregnancy status
Etiology of hypothyroidism
Degree of TSH elevation
Age
General clinical context, eg. cardiac disease
THYROID
Volume 24, Number 12, 2014
American Thyroid Association

16. Best approach to initiating and adjusting levothyroxine dosage
Initial full replacement or
Partial replacement with gradual increments in the dose titrated upward
Using serum TSH as the goal
Dose adjustments:
Large changes in body weight
Aging
Pregnancy
Assess TSH: 4–6 weeks after any dosage change.
THYROID
Volume 24, Number 12, 2014
American Thyroid Association

17. Potential deleterious effects of inadequate levothyroxine
Detrimental effects on the serum lipid profile
Progression of cardiovascular disease.
THYROID
Volume 24, Number 12, 2014
American Thyroid Association

18. Potential deleterious effects of excessive levothyroxine
Atrial fibrillation
Osteoporosis
Avoid subnormal TSH, particularly below 0.1 mIU/L, especially in older persons and postmenopausal women.
THYROID
Volume 24, Number 12, 2014
American Thyroid Association

19. Management of hypothyroidism in elderly patients
Initiate low dose and titrate slowly based on serum TSH
Normal TSH range is higher in older populations (such as those over 65 years)
Higher serum TSH target may be appropriate
THYROID
Volume 24, Number 12, 2014
American Thyroid Association

20. Management of hypothyroidism in pregnancy
Dose titration to achieve TSH within the trimester specific reference range
Check TSH every 4 weeks in the first half of pregnancy and less frequent later
Increase T4 dosage as soon as pregnancy is confirmed
THYROID
Volume 24, Number 12, 2014
American Thyroid Association

21. Management of hypothyroidism in infants and children
10–15µg/kg/d T4 should be initiated once newborn screening is positive, pending the results of confirmatory testing
Higher doses for infants with severe congenital hypothyroidism
Goal:
Serum thyroxine in the mid- to upper half of the pediatric and the serum TSH in the mid- to lower half of pediatric reference range
Check T4 & TSH 2–4 weeks after initiation of therapy
Once the proper dose is identified, surveillance testing should be performed every 1 to 2 months during the first
year of life with decreasing frequency as the child ages.
THYROID
Volume 24, Number 12, 2014
American Thyroid Association

22. Biochemical treatment goal in secondary hypothyroidism
Serum FT4 in the upper half of the reference range
However, the serum free thyroxine target level may be reduced in older patients or patients with comorbidities, who may be at higher risk of complications of thyroid hormone excess
THYROID
Volume 24, Number 12, 2014
American Thyroid Association