Retrospective #465: Diabetic neuropathic complications

If the subject matter of this post turns you off, good! I’m going to get personal, and I’m not especially fond of the idea of your reading about my bladder dysfunction. But the truth is, my urologist thinks, and my internist agrees, that as a 32-year type 2 diabetic, I may have begun to show a sign of diabetic neuropathy. His Dx: that I have a neurogenic bladder that appears to be responsible for a worsening eGFR. What’s that, you ask?

An eGFR, “estimated glomerular flow rate,” is a lab test of kidney function. It is a common marker for Chronic Kidney Disease (CKD) and is evaluated on a scale of declining kidney function (5 stages ending with end-stage kidney disease and renal dialysis. That “complication” is called nephropathy, one of three possible microvascular complications  of long-term type 2 diabetes. The third is retinopathy (leading to blindness).

So, what is a normal eGFR? According to Wikipedia, the National Kidney Foundation defines, “a normal GFR for adults as greater than 90 mL/min/1.73m².” “Because the calculation works best for estimating reduced kidney function, actual numbers are only reported once values are less than 60. Normal GFR values are largely over 60 in healthy subjects, at least before the age of 70 years. However, we know that GFR physiologically decreases with age, and in adults older than 70 years, values below 60 could be considered normal.”

My doctor began to request eGFR tests for me in 2011, one month before I turned 70. For three years, the next nine tests were all ≥60. Then, starting in 2015 (at age 73), 5 of the next 7 were below 60 (mostly low 50s); then, last summer I had a 43, which repeated at 47 and 45 (average of 3 = 45). I also wanted to know why I peed just a little and so often, so my urologist undertook a series of tests and examinations. We think we now know the answer.

I have a very large bladder – over a one-liter capacity – and it doesn’t completely empty despite the urethra having a clear passage through the prostate. The reason, apparently, is neuropathy: the muscle that normally contracts the bladder to make me “void” isn’t getting a signal to contract from my nervous system. Hence, the enlarged bladder and the frequent urge to urinate small amounts that I’ve observed since the beginning of the year. The urologist ordered a prescription to relax the muscle in the neck of the bladder, but it didn’t help.

As a result, his thinking goes, when my enlarged bladder is really full, and not emptying much, urine backs up the ureters to the kidneys; and puts back pressure on the kidneys. And this is beginning to cause the reduced kidney function (lower eGFRs). My internist concurred and added, for effect, that back pressure affects both kidneys, and I only have two! He also stressed that I must drink plenty of fluids because dehydration also causes kidney damage.

My urologist has now twice suggested that the best option for me at this point is self-catheterization. I have reluctantly come to the same conclusion. Ugh! My plan is to live to be 100, and to do that I’ll need my kidneys, such as they are. When I was in my 40s, the idea of taking a pill every day for the rest of my life was anathema. Now, I take a handful twice a day. So be it. At least I can say I am “otherwise healthy,” knock on wood.

The “plan” (the urologist’s ploy to get me to start) was to have me catheterize myself three times a day for a few weeks and then do another eGFR. If my kidney function improves, that is, if my eGFR increases, as he thinks it may, then I will have to continue with catheterization from that point forward (until I get to be 100), to preserve the benefits. Apparently, no other remedy is available for a neurogenic bladder.

Two subsequent eGFRs, performed at two-week intervals after catheterization began, were improved (53 and 55). A third, 2 months later, was, alas, back down to a disappointing 47. So, we’ll just have to “wait and see.”

Meantime, the message here is to take notice of changes in your daily habits (like frequency and amount of urination) and discuss it with your doctor(s) before you too have no choice but to “siphon the python.” Happy New Year!

Note: This blog was originally posted in January 2019. Since then, my eGFRs have been stable and above 45, and I continue to catheterize 3 times daily…in case you’re interested.