Do I have the mechanism figured out correctly? If not, please explain!
Patient who is hyponatremic and hypokalemic is given potassium chloride. Potassium enters cells to replace sodium which enters ECF and plasma. Because the BBB blocks potassium chloride from entering the brain, the increased tonicity of plasma draws water from the brain resulting in myelinolysis. [I read that potassium also takes the place of some intracellular hydrogen ions that are buffered in the ECF, essentially pulling some water and chloride into the cells with it. This should counteract the dehydration behind the myelinolysis if it also took place in the brain? So is potassium chloride basically entering the ICF compartment minus the brain and thus raising the tonicity of ICF - brain and ECF resulting in a net water movement out of the brain?]
Patient who is hyponatremic and hypokalemic is given potassium chloride. Potassium enters cells to replace sodium which enters ECF and plasma. Because the BBB blocks potassium chloride from entering the brain, the increased tonicity of plasma draws water from the brain resulting in myelinolysis. [I read that potassium also takes the place of some intracellular hydrogen ions that are buffered in the ECF, essentially pulling some water and chloride into the cells with it. This should counteract the dehydration behind the myelinolysis if it also took place in the brain? So is potassium chloride basically entering the ICF compartment minus the brain and thus raising the tonicity of ICF - brain and ECF resulting in a net water movement out of the brain?]