10-20-2008, 05:01 AM
10-20-2008, 05:10 AM
it's a paradox (and like any other paradox it doesn't really make sense)... i've been to many books on this topic and to summarize what i understood:
thiazides and amiloride cause loss of Na and water distally, but remember that this is minimal because most has already been reabsorbed proximally... now the slight dehydration causes decrease GFR and increase Na and water retention in the proximal parts of the nephron meaning LESS WATER DELIVERED TO THE COLLECTING DUCTS
the mechanism of indomethacin is related to its blocking of PGE (not sure exact details)
but the most important thing for the usmle is that the DOC for Neph DI is thiazide EXCEPT if the DI was caused by lithium in which case thiazides would increase lithium toxicity, so in such a case we would use amiloride..
thiazides and amiloride cause loss of Na and water distally, but remember that this is minimal because most has already been reabsorbed proximally... now the slight dehydration causes decrease GFR and increase Na and water retention in the proximal parts of the nephron meaning LESS WATER DELIVERED TO THE COLLECTING DUCTS
the mechanism of indomethacin is related to its blocking of PGE (not sure exact details)
but the most important thing for the usmle is that the DOC for Neph DI is thiazide EXCEPT if the DI was caused by lithium in which case thiazides would increase lithium toxicity, so in such a case we would use amiloride..
10-20-2008, 05:57 AM
Thanks hopinn99....you gave some reasonable reason....
Any other peer's opinion?
Any other peer's opinion?
10-20-2008, 06:35 AM
We had similar discussion long back.here is the link,if u find it useful.
http://usmleforum.com/showthread.php?tid=308648.php
http://usmleforum.com/showthread.php?tid=308648.php
10-20-2008, 07:59 AM
thanks shiney, i need to digest.... and i am not sure if thiazide etc. are just effective to lithium induced DI, instead of general....yes, i am pretty confused at this.