During a joint endocrinology and nephrology conference, participants are reviewing the diagnostic interpretation of polyuria. They are analyzing specific physiological responses to a carefully monitored water deprivation test, followed by the administration of exogenous subcutaneous desmopressin. Match each patient's physiological response pattern with the most accurate underlying diagnosis.
- Baseline serum sodium is 148 mEq/L. After prolonged fluid restriction, urine osmolality plateaus at 230 mOsm/kg. Upon administration of desmopressin, urine osmolality increases by 150%.Complete central diabetes insipidus
- Baseline serum sodium is 147 mEq/L. After prolonged fluid restriction, urine osmolality plateaus at 210 mOsm/kg. Upon administration of desmopressin, urine osmolality increases by only 4%.Complete nephrogenic diabetes insipidus
- Baseline serum sodium is 132 mEq/L. After prolonged fluid restriction, urine osmolality rises from 160 mOsm/kg to 720 mOsm/kg. Desmopressin is not administered as the test is terminated.Primary polydipsia
- Baseline serum sodium is 146 mEq/L. After prolonged fluid restriction, urine osmolality plateaus at 410 mOsm/kg. Upon administration of desmopressin, urine osmolality increases by an additional 25%.Partial central diabetes insipidus
Cevap
The correct matches correlate the baseline sodium, endogenous response to water deprivation, and exogenous response to desmopressin to distinguish the exact etiology of polyuria.
The correct matches map the precise physiologic feedback loops of the ADH axis. Central defects respond to exogenous hormone replacement, nephrogenic defects resist both endogenous and exogenous hormone, and primary polydipsia demonstrates a completely intact physiological response when water is withheld.
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Anahtar Kavram
Interpretation of the water deprivation test and desmopressin challenge in evaluating the differential diagnosis of polyuria.