Therapeutic target
Establishment of a euthyroid metabolic state (= thyroid levels in the normal range).
Therapy recommendations
- In hypothyroidism, a TSH level greater than 10 mU/l is considered an absolute indication for therapy. At the same time, free T3 and free T4 may be decreased.
- Pregnancy and childbearing as well as a goiter or a struma recurrence after resection are considered – even with values between 4 and 10 mIU/l – as absolute therapy indications.
- Under L-thyroxine therapy, the target value in younger patients is between 1 and 2.5 mU/l. After reaching the target value should be annual checks.
Note!Because between 5 and 10% of patients with hypothyroidism treated with L-thyroxine (T4) may still be symptomatic, combination therapy of L-thyroxine (T4) and triiodothyronine (T3) may be recommended. This combination therapy should be used today exclusively by internists or endocrinologists.The European Thyroid Association (ETA) has spoken out against a general therapy with this combination! Instructions for taking L-thyroxine:
- Take tablets in the morning on an empty stomach (at least 30 min before breakfast); if taken in the evening, a gap of at least 2 hours from the last meal is recommended (taking in the evening is the better option for absorption)
- Low starting dose (12.5-25-50 μg/d) and slow increase (by 12.5-25-50 μg/d) in elderly patients and cardiac-pregnant patients (“start low, go slow”)
- Dose escalation (at 2- to 4-week intervals) – until optimal dose is reached clinically and by laboratory diagnosis.
- In pregnancy, continue therapy consistently.
TSH control examination at the earliest 6 weeks after initial setting. If a TSH steady state is reached, the control intervals can be extended (every 6-12 months.
Amiodarone and thyroid dysfunction
In addition to amiodarone-induced hyperthyroidism (AIH), there is amiodarone-induced hypothyroidism (hypothyroidism) (amiodarone-triggered autoimmune thyroiditis/thyroiditis).Amiodarone does not need to be discontinued in amiodarone-induced hypothyroidism!
Hypothyroidism/latent hypothyroidism and type 2 diabetes mellitus
According to a long-term study, type 2 diabetic patients treated with metformin and simultaneously treated with L-thyroxine for hypothyroidism more often had suppressed TSH levels (decreased TSH levels). This association was not seen in patients with normal thyroid function.
Hypothyroidism/latent hypothyroidism and pregnancy
Therapy Recommendations
- Based on the Endocrine Society International Guidelines, the TSH threshold for intervention is 2.5 mIU/l in the first trimester (third trimester) and 3 mIU/l in the second and third trimesters
- Clinical hypothyroidism is present at a TSH level > 10 mIU/l regardless of the concentration of free T4, and at elevated TSH levels associated with a T4 level < 9.7 pmol/l ( 7.5 μg/l)
Hypothyroid coma (myxedema coma)
- Intensive care monitoring
- Thyroid hormone substitution: parenteral (“bypassing the intestine,” i.e., e.g., injection into the vein) substitution of T4 (L-thyroxine)
- Glucocorticoid substitution
- Supportive measures
- Compensation of fluid and electrolyte disturbances (usually there is hyperhydration / overhydration) – due tohydration note the reference under hyponatremia.
- Hypoglycemia (hypoglycemia): glucose infusions.
- Hyponatremia (sodium deficiency): water restriction alone, no rapid compensation (thyroid hormone administration causes the kidney to reabsorb sodium)
- Hypotension (low blood pressure): hydrocortisone (note: catecholamines and digoxin are less effective; these agents increase risk for arrhythmias)
- Nonpharmocologic measures:
- Intubation (insertion of a tube (pipe) to secure the airway) and ventilation.
- Measurement of central venous pressure (CVP).
- Close monitoring of diuresis (urine output).
- Therapy of hypothermia (hypothermia):
- Treatment of the underlying disease or the triggering cause.
- Z. B. Therapy evtl. infections (antibiotic administration).
