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.

I've posted several times. Quick recap: My local nephrologist diagnosed me with ADPKD. Mayo Clinic ordered a genetic test and it came back negative. I do not have this disease. My low eGFR is due to long-term lithium use (35 years). Dr. Dahl explained in my Zoom appointment yesterday, that end-stage kidney disease is unlikely from lithium use. We will follow up with bloodwork. BUN is 29. She did not think that was a concern. Many people can live years with a range of mid to low 20s eGFR with my disease - Nephrogenic Diabetes Insipidus (not be confused with diabetes). I have no symptoms. I feel great with energy but watch my diet, salt, and potassium, and drink lots of water. All my blood levels are normal except for calcium, but not a concern unless it rises significantly.
I plan to keep my relationship with Mayo on a yearly basis. This surprises me. But I trust Dr. Dahl, an expert and so knowledgeable. So I will continue to live normally, I guess 🙂

I personally know three people with severe kidney disease from Lithium. My daughter has been on it for 14 years. That may not be your issue. But I am surprised that a nephrologist would say that and wonder if it is true, for my kid's sake.

Here is an excellent article that goes into detail about lithium and kidney disease. There is clearly not enough research to verify the risk of ESRD and lithium use. That is why I requested an ongoing relationship with Mayo just in case I get to the ESRD place. If I need a transplant, that's where I want to go. My local nephrologist kept telling me "No worries, you'll live to 100" which is one of the reasons I made the appointment at Mayo. There is no treatment for damaged kidneys from lithium use. But I didn't want to be coddled into thinking there's no risk.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5537577/
"There are conflicting studies in this article. There is not enough research.
Discrepancies among studies were largely due to methodological differences such as varied parameters to assess renal function and definitions of renal impairment, short-term follow-up, a lack of patients on long-term lithium therapy, combining high-risk and low-risk groups, choice of control group (healthy v. psychiatric patients), and an inability to control the confounding variables. Definitive data on the magnitude of the risk are still lacking. Moreover, in the absence of any pathognomonic histological or biochemical changes, lithium-associated CKD remains a diagnosis of exclusion."

My friend told me she has an eGFR of 17 from Lithium. I assume her doc told her Lithium was the culprit.

How does she feel, does she have adverse symptoms? I mentioned in another post my cousin has lived with eGFR 20 for over 10 years. Her kidney disorder is due to taking ibuprofen every day for years. Many medications can damage the kidneys over time. Honestly, lithium gave me a normal, happy life for many years. I'm 65 now and would not do anything differently. It's a risk that was worth it to me.

@windyshores I always need to remember that every person is different. Not only how a chronic issue presents itself, but how our body responds to a stimulant. That is, how we deal with a medication may have some similar effects/side effects, but still be different. Like you, I have known people with kidney issues from Lithium use. And, like @mrainne, I know people who have had no issues with it.
Ginger