Hi Sarah,
The salt from your crisps and also from the bread probably helped you avoid stomach problems (as it helps your stomach to produce appropriate strength stomach acid). I can see from the fact that you eat bread too, that you don’t have overt gluten issues, which is another bonus.
However, I am surprised that this salt didn’t prompt you to drink adequately. POTS is also linked to dehydration, you need both salt and water to remain properly hydrated. In fact people who drink loads of water (over-hydrate) also need many other minerals too, as they are constantly flushing these out from the body.
It’s good that you weren’t taking pain-killers or antacids which worsens any Magnesium deficiency BUT were you getting sufficient from your diet ? Magnesium helps loosen bowel movements and keep things moving, so again the fact that you were constipated suggests that maybe you weren’t getting enough from your diet. Foods rich in Magnesium are Nuts, Vegetables and Pulses (Beans, Butterbeans, Red Kidney Beans, Chick Peas, Lentils, etc). Some people think that they are ok, as they are getting plenty of vegetables and salad in their diet BUT if they don’t take in enough fat, they cannot absorb the nutrients from those foods. I can see you eat sandwiches, so that would incorporate butter yes ? so that’s good. I wouldn’t take magnesium supplements though – just sufficient salt, a magnesium rich diet, enough fat and regular baths in Epsom Salts should suffice.
Regarding your concerns, check out about Lumbar Puncture risk and alternatives at:-
http://prettyill.com/forums/viewthread/993/#4251
Plus further info explaining the danger of Lumbar Puncture at:-
http://prettyill.com/forums/viewthread/712/#3966
Barbara
(UK)