SIADH = low specific gravity?

Nursing Students Student Assist

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Specializes in Surgical Nursing.

:confused:

So I know that with DI the specific gravity is low b/c the urine is dilute, but in SIADH, why is the specific gravity low when water is being retained? Is it because that water is being retained else where, blood, and not going through the kidney tubules? HELP! :(

I've read threads on here and researched online... :(

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Specializes in med/surg, telemetry, IV therapy, mgmt.

Specific gravity is not low in SIADH. It is high. SIADH is not caused by decreased renal excretion of water. Serum sodium and osmolarity are reduced. The kidney continues to excrete sodium and urine specific gravity is elevated although urine volume is decreased or water is absorbed (page 92, Pathophysiology: The Biologic Basis for Disease in Adults and Children, third edition, by Kathryn L. McCance and Sue E. Heuther).

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Specializes in CTICU.

SIADH = reduced UO with increased SG.

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^ what they said :) I had trouble understanding that when I went through it as well - also you need to beware some textbooks, have caught quite a few editing mistakes that could make a sane person insane.

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Specializes in Surgical Nursing.

i knew it! the textbook has a mistake that's driving me insane! thank you all so much! =)

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