Nephrogenic Diabetes Insipidus Diagnosis

OP here. I forgot to mention I've been intermittent fasting since 2017 and my weight and BP has been normal ever since. My weight is 133 and my BP ranges from 107/72 to 123/78 or so, rarely going higher only after exercise. But my eGFR keeps declining.

@mrainne welcome to Mayo Clinic Connect.
First I’ve never heard of Nephrogenic Diabetes Insipidus. I’ve got some learning to do!
Second I’m somewhat familiar with poly cystic kidney disease (PKD), but I have chronic kidney disease (CKD) and lowering eGFR.
Third being bipolar and on Lithium can be tricky as you probably already know. Are your Lithium level labs and dose still monitored by the prescribing Dr.? Sometimes when you’ve been on a medication a long time, an adjustment becomes necessary. Sometimes meds can be flushed out of your system with too much hydration. Ask your provider to make sure nothing like that is happening. I don’t know if that has anything to do with declining eGFR but it’s worth asking about.
Fourth your weight and blood pressure are good so you are doing a good job taking care of yourself.
Fifth going to Mayo is a good thing. You are in great hands there. Their collaborative team approach will get to the bottom of this.
My hope and prayer for you is a thorough diagnosis and comprehensive plan to help restore you to as good as you can be! Keep us posted?

Thanks! My PCP and psychiatrist took me off lithium in 2014 when my GFR started to go below 60 and my creatinine went up to 1.1. I’m on lamotrigine now which works perfectly. I wish I switched many years ago, but here we are. It looks as though the lithium damage is irreversible. I’ve been reading research from the NIH and many people who are or were on lithium for way fewer years than me have irreversible kidney damage. Research is also showing lower levels of lithium work as well and may not damage the kidneys.

Now my mission is to hopefully, keep my kidneys from degrading too fast. If I can be stable I’m good because right now…I have no adverse symptoms. I would not know my kidneys are failing without the intervention of my docs and blood tests. This seems to be the case with most kidney disease. The race is then to keep our kidneys from further damage. So, low salt, low protein, lots of water, and weight in check. I don’t drink alcohol and I exercise, not too much so my creatinine levels don’t go up.

I met with Dr Neera K Dahl, a ADPKD specialist at Mayo. She as well as the radiologist who read my 2017 CT scans do not believe I have PKD. They believe my kidney issue I’d from the long term use of lithium. This is good news because I don’t have to worry about two diseases.

We are waiting for the results of a genetic test to be 100% sure. Our appointment in August will be a better understanding of what I need to do and what I’m looking at for the future.