OUWB Non-anion gap question

Where does the chloride come from.

XXXXX and I had a question following the Acid-Base workshop. What is the origin of the increase in chloride ions in patients with NAGMA due to GI or renal causes?  

Thanks, 

So the key here is not to think of the body as static. As patients lose bicarb in the stool or in the urine, this will result in volume depletion which will be compensated for by renal retention of sodium and yes, chloride.

Great review of non-anion gap metabolic acidosis here:

Differential Diagnosis of Nongap Metabolic Acidosis:Value of a Systematic Approach