Hypothyroidism

Endocrine · ~6% of blueprint

Pathophysiology: Inadequate thyroid hormone — most often Hashimoto’s autoimmune thyroiditis.
Signs & Symptoms: Fatigue, cold intolerance, weight gain, constipation, dry skin, bradycardia, delayed reflexes.
Gold Standard Diagnosis: ↑ TSH with ↓ free T4 (primary); positive anti-TPO antibodies in Hashimoto’s.
First-line Treatment: Levothyroxine, titrated to normalize the TSH.

High-Yield Pearl

TSH is the initial test of choice; peak effect of a dose change takes 4–6 weeks, so recheck then.

Sources

Reviewed September 2026

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