Figure 1: Electrolyte abnormalities in patients with ileal and/or colonic OBS. (1) absorption from urine which dissociates to H+ and NH3 resulting in metabolic acidosis. (2) Cl is exchanged with and transported into blood. (3) Na+ is displaced by and not absorbed by bowel resulting in a net loss. (4) There is a net loss of H2O resulting in dehydration and loss of Na+ due to NB secretion of Na+ into urine. (5) Elevated aldosterone levels due to Na+ loss precipitates K+ loss from renal tubules. Na+: sodium; K+: potassium; : ammonium; NH3: ammonia; : bicarbonate; H+: hydrogen; H2O: water; Cl: chloride; NB: neobladder.