Polycystic Kidney Disease (PKD) Support Group
Polycystic kidney disease (PKD) is a progressive, genetic disorder of the kidneys. It occurs in humans and other organisms. PKD is characterised by the presence of multiple cysts (polycystic) in both kidneys. The disease can also damage the liver, pancreas and rarely the heart and brain.
Hope you find some answers. Good luck.
Numerous bilateral cysts does suggest the possibility of PKD, but there are other cystic kidney diseases (see here:http://emedicine.medscape.com/article/453831-overview)
PKD is by no means certain, therefore, but it is unlikely to be simple cysts as these tend to be 1 or 2 in number. On the other hand, PKD can cause cysts on other organs such as the liver (I have an unusually extreme version of this and my liver is enormous owing to the presence of so many cysts).
Your usual BP is very low, so that is a bit of a mystery. PKD often causes enduring high BP. I have not heard of urinary retention being a problem with PKD either, so clearly something else is going on to cause this such as blockage of the ureter. I'm actually wondering whether you might have medullary sponge kidney.
https://www.niddk.nih.gov/health-information/kidney-disease/children/medullary-sponge-kidney
The urologist may have some pointers for you, but as has been said previously, I would imagine that you will need to see a nephrologist as well.
A normal kidney can have up to 5 cysts. Any more is abnormal, though not necessarily serious. This may help clarify a little:
http://www.kidney.org.uk/help-and-info/medical-information-from-the-nkf-/medical-info-kidney-disease-symptoms/medical-info-kidney-disease-cysts/
One hepatic cyst is not unusual, however. Urologists are not the best people to see about kidneys. I saw a urologist at the start of the diagnosis process and he told me I needed to see a Nephrologist. This is what I would suggest that you should do. The urologist is wrong to say that cysts have to be huge for it to be PKD; they can be any size at all. This could still be PKD or Medullary sponge/cyst kidney but will not necessarily lead to kidney failure. See a nephrologist.
Since your urologist suggested a GI doctor, could you perhaps go down that route and then see whether the GI doctor will refer you to a nephrologist? It's tortuous but may be a solution. Are you still taking Fludrocortisone? If it is for problems with the adrenal glands, this may explain the low BP apparently. From what I can see, it can have many possible side effects. As you say, if you have PKD (and it's quite a big if), low BP is in your favour. Hopefully you will remain stable and not be too troubled by these issues.