Endocrinology and Metabolism
Endocrine questions require pattern-based diagnosis using dynamic tests and an understanding of feedback loops. Candidates must master diabetes: diagnostic criteria, distinction between type 1 and type 2, acute complications (diabetic ketoacidosis vs hyperosmolar state), and chronic complication screening. Know thyroid disorders: primary versus secondary hypothyroidism, Graves disease versus toxic nodule, and the interpretation of TSH with free T4. Understand adrenal insufficiency and its crisis, calcium and parathyroid disorders, and the approach to incidental adrenal or pituitary findings.
Traps: diagnosing hypothyroidism from a low free T4 without checking TSH; missing diabetic ketoacidosis because glucose is only moderately elevated; confusing primary hyperaldosteronism with essential hypertension; forgetting that steroid use suppresses the adrenal axis.
Worked example: a patient with polyuria, weight loss, and ketones in urine. The diagnosis is diabetic ketoacidosis regardless of the exact glucose value. Management priorities are fluids first, then insulin, with potassium monitoring and replacement as needed, because insulin drives potassium into cells and can precipitate hypokalemia.
Rule of thumb: in endocrine testing, always ask whether the abnormality is primary (gland) or secondary (pituitary/hypothalamic) by reading the feedback hormone. A low free T4 with high TSH is primary hypothyroidism.
Key concepts: feedback-loop interpretation, diabetes diagnosis and complications, thyroid patterns, and adrenal crisis recognition.