Struggling to tell DI vs SIADH apart on test day? This episode breaks it down step-by-step—starting with a classic USMLE-style question and ending with the high-yield patterns you need to answer fast and confidently.

We kick things off with a patient presenting with polyuria, polydipsia, hypernatremia, and dilute urine after starting a mood stabilizer—can you identify the diagnosis and next best step? From there, we walk through the full framework for approaching water balance disorders.

In this episode, you’ll learn:
• How to interpret serum vs urine osmolality like a pro
• The key differences between central vs nephrogenic diabetes insipidus
• Why desmopressin response is the ultimate diagnostic clue
• The mechanism behind lithium-induced nephrogenic DI (and why amiloride is the answer)
• A clear, test-day comparison of DI vs SIADH
• High-yield treatment strategies you’ll see on Step 2