Oral and intravenous hydration in the treatment of orthostatic hypotension and postural tachycardia syndrome, 2022, Howard Snapper et al

Abstract

Hydration with water and salt is the mainstay of treatment for autonomic nervous system disorders that impair orthostatic tolerance. The goal is to expand intravascular volume to compensate for the downward displacement of blood volume that occurs when standing and thereby sustain cerebral perfusion and restore quality of life. Despite strong consensus recommendations for salt supplementation as standard treatment of these disorders, published evidence of benefit is relatively weak, and no randomized clinical trials have occurred. This review summarizes the physiological rationale for hydration and evaluates the literature on oral and intravenous hydration in the treatment of neurogenic orthostatic hypotension, postural tachycardia syndrome, and recurrent vasovagal syncope.

We conclude that oral salt replacement is indicated for treatment of neurogenic orthostatic hypotension because these patients have excessive renal sodium excretion, and for treatment of chronic orthostatic intolerance because these patients are often hypovolemic. As not all patients are able to tolerate sufficient oral hydration, there is also a role for intravenous volume-loading in severe cases of postural tachycardia syndrome. We offer guidance, based on review of the literature and the clinical judgment of a cardiologist and neurologist with experience treating autonomic disorders, regarding the option of ongoing intravenous hydration for treatment of severe, refractory cases of postural tachycardia syndrome.

https://www.sciencedirect.com/science/article/pii/S1566070222000108

 

That seems to say it all. The enthusiasts believe the treatment works despite having no reliable evidence. Looking through the paper the physiology does not look convincing. I very much doubt salt and water are a good idea for OI except in very specific salt-wasting conditions.

 

Salt water has sometimes had a strong positive effect on my chest pain when it was bad, in 10 minutes.

 

My understanding is that hormonal changes and low levels of thyroid hormone can also cause low blood-sodium levels?

I started feeling improvements many years ago when upright when I increased my sodium. So perhaps I don't have OI but imbalanced hormone levels instead.

 

I don't think thyroid status has much to do with salt and water. The obvious hormonal indication for salt is Addison's.

 

For my part, the only thing I can say about this is that following the POTS diagnosis, I did try drinking saline water as recommended... no effect, except to make me go to the bathroom more often.

 

I also found these somewhat "standard" POTS recommendations to be pretty weak.

Lots of companies marketing salt supplements and drink mixes on Amazon. Doesn't surprise me that there's not a lot of evidence.