Sms & Sns of hypothyroidism differ in relation to the deficient amount of thyroid hormone & rate acuteness deficiency appears.
Sms & Sns of hypothyroidism differ in relation to the deficient amount of thyroid hormone & rate acuteness deficiency appears. Several manifestations of hypothyroidism reflect the lack of thyroid hormone in two ways:
(1) Global 👉slowing of metabolic activity &
(2) Accumulated 👉 glycosaminoglycans in interstitial space of systemic organs.
Other Sms & Sns include depression, diminished hearing, diastolic HT, & pleural & pericardial effusions. Clinical picture of central hypothyroidism is like that of primary hypothyroidism. If hypothyroidism induced by hypothalamic-pituitary lesions, manifestations of associated endocrine deficiency e.g., hypogonadism & adrenal insufficiency can mask that of hypothyroidism. Multiple metabolic alterations including hyponatremia, hyperlipidemia, anemia, & high muscle enzymes. Diminished clearance of: anti-seizures, anti-coagulants, hypnotic, & opioids drugs can be also observed.
Kidney affection: 👉 Reversible rise in SCr observed in 20-90 % of hypothyroid ptns.
Treatment of primary hypothyroidism in adults
Frank primary hypothyroidism is characterizing by high TSH (thyroid-stimulating hormone) + Low free thyroxine (T4). Overt primary hypothyroidism needs ttt, regardless of Sms, unless it’s transient (as after painless thyroiditis or subacute thyroiditis) or reversible. Target of therapy:
(1) Alleviation of Sms,
(2) Normalized TSH,
(3) Decreasing goitre size (if present), &
(4) Avoiding over-ttt (iatrogenic thyrotoxicosis). 💣
We aim to keep serum TSH within the normal reference range (about 0.5-5.0 mU/L). It is crucial to notice that there’s an age-related shift towards elevated TSH in elderly, with its upper normal limit = 7.5 mU/L in 80 y. olds.
Ttt of choice to correct hypothyroidism is synthetic thyroxine (T4, levothyroxine). For most ptns, it is better not to combine T4-triiodothyronine (T3) in therapy. However, T4-T3 therapy may improve Sms in certain ptns (e.g., post-thyroidectomy or ablation with radioiodine). Combined therapy is discouraged with the following:
(2) Pregnant women.
(3) CVS disorders (excess T3 can induce arrhythmia).
If T4-T3 therapy is used, T4-to-T3 ratio should be about 13:1 to 16:1. Remaining on the same formula of T4 is advised. Either a generic or a brand-name formula is accepted. With switching from one manufacturer to the other, we should measure TSH 6 wks after shifting the preparations to maintain TSH within its therapeutic level.
Initially, full dose (1.6 mcg/kg/d) in young, healthy ptns, but older ptns & CAD ptns should commence at a lower dose (25-50 mcg/d). T4 must be given on empty stomach, ideally 30-60 min before breakfast. After commencing T4 therapy, ptn should be re-evaluated & TSH should be re-measured in 6 wks with dose adjustment accordingly. Sms may start to resolve after 2-3 wks, but steady-state TSH will not reached before at least 6 wks. If ptn showing hypothyroid Sms & TSH is confirmed by frequent testing to be at the upper limit or above the reference level, it’s accepted to increment the dose & to aim for TSH in its lower ½ of normal range; however, improved Sms with higher doses may rely on expectation rather than true physiologic benefit.