Endocrinology & MetabolicPending review

Hypothyroidism

A state of thyroid hormone deficiency that slows metabolic rate in virtually every tissue, so the whole clinical picture (from bradycardia to cold intolerance to slowed cognition) can be predicted simply by asking what happens when metabolism runs too slowly.

First principles

Thyroid hormone sets the metabolic idle speed of almost every cell

Thyroxine (T4) and triiodothyronine (T3) increase basal metabolic rate, oxygen consumption and protein turnover across nearly all tissues. When levels fall, cellular metabolism slows down uniformly rather than in one organ, which is why hypothyroidism produces such a broad, multisystem picture: every symptom is really the same mechanism (reduced metabolic drive) expressed in a different organ.

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Educational content pending clinical review. Not medical advice.