Just had blood work done yesterday, and my blood plasma sodium levels were just below the minimum. I know that I crave salt, my electrolytes are always low, and a saline drip IV makes me feel much better than normal. So I did some reading, and here's what I found:
Low blood plasma sodium is also known as HYPONATREMIA.
From this article: http://www.nlm.nih.gov/medlineplus/ency/article/000394.htm
When the amount of sodium in fluids outside cells drops, water moves into the cells to balance the levels. This causes the cells to swell with too much water. Brain cells are especially sensitive to swelling, and this causes many of the symptoms of hyponatremia.
Common symptoms include:
- Loss of appetite
- Muscle spasms or cramps
- Muscle weakness
Hyponatremia can also actually CAUSE brain herniation due to the additional swelling in brain tissues.
Another article, titled Hyponatremia in Emergency Medicine discusses hyponatremia can be caused by excess levels of ADH (antidiuretic hormone).
From this article: http://emedicine.medscape.com/article/767624-overview#a0104
ADH is also secreted in response to hypovolemia, pain, fear, nausea, and hypoxia.
Hypovolemia is low blood volume, and hypoxia is parts of the body having low oxygen levels.
I'm not sure if it's possible to measure ADH levels, but I imagine most of us have constant pain, and sometimes constant nausea.
I don't believe Chiari is caused by low salt levels, and just eating extra salt isn't a fix for the symptoms of hyponatremia, but I do think that if you have blood work done in the near future, it's something for your doctor to check. I think that having low salt levels can make symptoms worse for Chiari patients due to additional swelling in an area that's already crowded.
As a side note, ADH is also known as vasopressin: http://en.wikipedia.org/wiki/Vasopressin
The two primary functions of ADH/Vasopressin is to retain water in the body and to constrict blood vessels. For those of us with POTS, this is important since our blood vessels don't constrict very well, which causes the blood pressure drop and heart rate increase.
Long story short here, until they figure out what causes the low sodium/excessive water issue, saline drip IV seems to be the most effective method of raising blood plasma volume and salt levels.
Here's a great article from a POTS patient discussing the benefits of saline drip therapy.