Adult Dysautonomias Part 2: POTS and Related Conditions

Now we’ll go into some of the symptoms of POTS.  POTS is very common, it’s almost always in women, for reasons that nobody knows and usually in Caucasian women and I am not sure that’s a socioeconomic thing, but I don’t think anybody knows why that’s true either.  Unfortunately, these aspects which are kind of glaring, are not really researched.  I don’t know why women are so predominately represented in terms of occurrence of POTS.  Key symptoms of POTS include: fatigue and there is a major overlap between POTS and chronic fatigue syndrome, another major complaint is brain fog which is very poorly understood, there’s abdominal pain, bloating, gastroparesis, nausea makes you wonder about the Sota story and the role of catecholamines in decreasing gastric transit.  I think an algorithmic approach to POTS is valuable clinically; there’s a zillion causes, as you can see.  I think my bias is that most of POTS is secondary to drugs first and then secondary to low central blood volume.  Low central blood volume could be from excessive venous pooling or because of low blood volume.  And then there are primary causes of POTS which get a lot of attention, but I think are relatively uncommon.  I think this is the main cause.  This is a research-y kind of question and should be answered if there’s support for the research.  There’s an association between POTS and joint hypermobility, in other words, being double jointed.  It’s a whole area of research that I think is quite interesting, but certainly in a patient who you evaluate who has POTS as part of your autonomic history, “Can you do weird things with your limbs that other people can’t?”.  This is designed to illustrate that POTS and syncope can happen together, they’re not necessarily different conditions.  So, here is a patient who had a tremendous increase in heart rate, shown here, and a lot of blood pressure oscillations, which I don’t want to get into, and then subsequently had a tilt-evoked hypotension and syncope.  So, they can occur in the same individual.  I think there’s an important interaction between the autonomic nervous system and immune system in dysautonomias – it’s not really well researched.  This is an example of this, it’s called mast cell activation syndrome.  Pretty straightforward, mast cells when stimulate, degranulate and then by way of exocytosis, remember that’s the omega sign, histamine gets released and this causes relaxation of blood vessels.  When the blood vessels are relaxed like that, blood pressures going to go down so sympathetic outflow could go up as a result, it’s just a guess.  I’m sure that this is a ripe area for research, the interactions between the autonomic and immune systems.