I presume that your sodium levels are quite low to potassium in which case this is a sign of severe adrenal insufficiency more than likely caused by a chronic infection. See my blog post about this and get the book from Adelle Davis I mention http://patrickrambling-pb.blogspot.com/2012/02/...
Davis mentions if the adrenals have fallen that far then sodium is what is needed (along with potassium) this is what I had to do for sometime. Occasionally need a shot of sodium. If you are craving salty foods then this could be a sign of sodium depletion.
Adrenals manufacture mineralcorticoids that regulate electrolytes including sodium, potassium, magnesium and chloride. Electrolytes are critical for many functions including nervous system, cardio and other things. IonCharge from Source Naturals is a good product that can help, also Himalayan Salt is good as well. Magnesium plays a key role in balancing the other electrolytes and is a critical and overlooked mineral.