The pathophysiological mechanism of beer potomania can be understood through an example. Imagine someone who binged on 4 liters of beer (which essentially means 4 liters of water) with ingestion of roughly 200 mosm that day. To place this in context, a normal American diet contains 750 mosm/day, and all of it is excreted in urine to maintain a steady state. As a result of the ingestion of this large amount of beer (i.e.free water), the patient’s anti-diuretic hormone (ADH) (the hormone that causes the kidney to reabsorb free water) secretion is at its minimum to allow the kidneys to excrete maximally dilute urine. Since the maximal dilution that can be attained is 50 mosm/L, the kidneys will excrete all the 200 mosm in the diet in 4 liters of urine (50mosm/L X 4L = 200 mosm). This will indeed maintain his sodium level. If this person in our example drinks his 5th liter of beer without taking any further osmoles, then he will become hyponatremic. This is beer potomania.

Template:WikiDoc Sources