Hyponatremia a diagnostic approach

4/19/2013 CME Hyponatraemia: an evidence-based approach Hyponatremia a diagnostic approach Dr Steve Ball The Medical School Newcastle Endocrinolo...
Author: Naomi Griffith
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4/19/2013

CME Hyponatraemia: an evidence-based approach

Hyponatremia a diagnostic approach

Dr Steve Ball The Medical School

Newcastle

Endocrinology

The trouble with guidelines why we struggle 

Too complex



Too simple They don’t say anything useful Contradictory …..Evidence-based?



  

more information than need

Newcastle

Endocrinology

1

4/19/2013

Diagnostic algorithms what’s new? 

Design



Evidence-based approach

 

user-sensitive weighting proportionate to diagnostic utility   

urine osmolality urine Na+ volume status

Newcastle

Endocrinology

Traditional algorithms clinical assessment of volume status is not reliable 

How good is assessment of volume status? 

hypovolemia, euvolemia, hypervolemia   



sensitivity 0.49 specificity 0.47 independent of Na+ status

How useful is assessment of volume status? 

do algorithms based on volume status work?



impact of removing ECF assessment

 

frequent misdiagnosis substituting frurate excretion improves accuracy

Musch W, Thimpont J, Vandevelde D, Verhaeverbeke I, Berghmans T, Decaux G 1995. Combined fractional excretion of sodium and urea better predicts response to saline in hyponatremia than do usual clinical and biochemical parameters.The American Journal of Medicine 98: 348-355 Fenske W, Maier SKG, Blechschmidt A, Allolio B, Stork S. 2010 Utility and limitations of the traditional diagnostic approach to hyponatremia: a diagnostic study The American Journal of Medicine 123: 652-657

Newcastle

Endocrinology

2

4/19/2013

Hyponatremia diagnostic pathway Exclude non-hypotonic hyponatremia Acute or severe symptoms? Yes

No

Urine osmolality

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