NBME 20 Urine Na+: increased; Serum osmolality: decreased (NBME Answers)

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submitted by hayayah(1056),

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hello Why would body respond to water retention with ALDO? ALDO would increase water retention... +6

nala_ula @hello, the body's response is to decrease Aldosterone since there is increased volume retention and subsequently increased blood pressure. This concept confused me a lot, but I ended up just viewing it as separate responses. First, the increased volume retention leads to increase ANP and BNP secretion that lead to decreased Na+ reabsorption in the tubules (page 294 in FA 2019) and second, this increased volume basically leads to increased pressure so lets also decrease aldosterone so there is no Na+ retention (since water comes with it)... I thought it was counterintuitive to secrete so much Na+ since you're already having decreased serum osmolality (decreased Na+ concentration) because of the water retention, but I'm guessing that this is just another way our body's well intentions end up making us worse XD +32

compasses see page 344 FA2019 for SIADH. +

dickass author pasted text straight from FA but the arrows didn't copy over, inverting the original meaning +3

medninja The idea of increasing urine Na is getting rid of water, thats why this mechanism end increasing urine Na secretion even when there are very low serum Na levels. +