In hypoosmolar hypovolemic hyponatremia, which laboratory pattern supports the diagnosis?

Prepare for the ITE Nephrology Test with a comprehensive study guide. Engage with flashcards and multiple-choice questions. Each question provides hints and explanations to help you succeed!

Multiple Choice

In hypoosmolar hypovolemic hyponatremia, which laboratory pattern supports the diagnosis?

Explanation:
Hypovolemic hyponatremia is a prerenal state where reduced effective circulating volume triggers ADH release and sodium conservation. The kidneys respond by reabsorbing sodium to restore volume, so urinary sodium is very low (often well below 20 mEq/L). Reduced renal perfusion also raises urea reabsorption, increasing the BUN/creatinine ratio (typically >20:1). ADH keeps water reabsorbed, producing a concentrated urine with high osmolality (usually >450 mOsm/kg). This pattern—low urine sodium, high BUN/Cr ratio, and concentrated urine—best supports hypoosmolar hypovolemic hyponatremia. Patterns with high urinary sodium, dilute urine, or low osmolality point to other causes rather than this scenario.

Hypovolemic hyponatremia is a prerenal state where reduced effective circulating volume triggers ADH release and sodium conservation. The kidneys respond by reabsorbing sodium to restore volume, so urinary sodium is very low (often well below 20 mEq/L). Reduced renal perfusion also raises urea reabsorption, increasing the BUN/creatinine ratio (typically >20:1). ADH keeps water reabsorbed, producing a concentrated urine with high osmolality (usually >450 mOsm/kg). This pattern—low urine sodium, high BUN/Cr ratio, and concentrated urine—best supports hypoosmolar hypovolemic hyponatremia. Patterns with high urinary sodium, dilute urine, or low osmolality point to other causes rather than this scenario.

More Multiple Choice Questions
Subscribe

Get the latest from Passetra

You can unsubscribe at any time. Read our privacy policy