Bladder changes in CES: not just incontinence!

FFS...

Thanks for reading the 47th edition of my newsletter. This newsletter tracks my research as I write a book about sciatica, and another one about cauda equina syndrome.

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Last week's newsletter finished on the topic of bladder dysfunction in CES. I thought it would be good to pick up on that today. For me, it was always the most confusing symptom of CES. So let’s try to understand bladder dysfunction and how to ask about it. As with the last email, I’m basically going to try to write something I would have liked to have read a few years ago…

Put very simply, the bladder uses the S2-4 nerve roots roots to send "I'm full!" messages to the brain and spinal cord. And the brain and spinal cord use those same roots to send "Okay, empty out" messages back the other way.

But as we know, with CES the sacral nerve roots stop carrying those messages. Consequently, the bladder can’t send any "I'm full" messages and can’t receive any "Okay, empty out" messages. Essentially, it's cut off from the brain and spinal cord. Incommunicado. Left to its own devices, it fills up and up without ever emptying out. This is called retention. And when the bladder finally gets so full that it can't hold any more, urine leaks out through the urethra. This is called overflow incontinence.

However, as we saw last week, CES unfolds over time. Retention and overflow incontinence are the end stage, a complete conduction block, “lights out”. And before retention and incontinence, when the conduction block in S2-4 is not yet complete, there are less obvious symptoms of bladder dysfunction. This recent paper helpfully breaks up these earlier symptoms into Frequency, Flow and Sensation.

From Lavy et al. 2021

So let’s look at each in turn.

First, Frequency.

Fairly obviously, you're looking for decreased frequency. Unless everything happens extremely quickly, then between normal urinary frequency and full urinary retention, there is probably going to be at least a short period of decreased frequency. For example, someone with CES might find they can go til lunchtime without needing to urinate.

Less obviously though, you also want to keep an eye out for increased frequency. This is because when "Okay, empty out" signals are weaker, the bladder is prone to incomplete emptying. And if the bladder doesn’t empty completely, it will have to try again before too long. Increased frequency.

So when it comes to frequency, although decreased frequency is the classic symptom, increased frequency should make you raise an eyebrow, too. We’re really looking for any frequency change.

Here are some questions you might find useful if you want to know more about your patient's urinary frequency:

• “Do you find yourself peeing more or less often?”

• “When did you last urinate?”

• “Do you get to lunchtime and notice you haven’t been for a wee all day?”

• “If you’re going more often, do you feel like you’re finishing when you go?”

• “You said you’re going more/less often, are you drinking more/less fluids?”

Next, Flow.

An incomplete conduction block in S2-4 means fewer “Okay, empty out” signals. And fewer “empty out” signals means a weaker bladder muscle contraction and therefore a weaker flow. For example, when someone with CES urinates, it might come out as a sputter or a dribble. Or they might find they have to strain to get it out. Or it might take some time to get going, so that although they feel like they want to urinate they find themselves waiting for a minute before they can do so (which is called urinary hesitancy).

As well as “Okay, empty out” signals, the brain also sometimes needs to send down “Hold it in!” signals, too. When these are impaired by CES, someone might find it difficult to stop urinating once they’ve started, or difficult to hold it in when they feel the need to go.

Here are some questions about urinary flow:

• "Is the stream normal? Does it feel like it's coming our with the same power?” “For example, does the stream spray, or come out thinly, or drip?”

• “When you need to go, is it possible to go? Do you have to force it or strain?”

• “When you go for a wee, does it come out when you want it to come out, or do you have to wait?”

• “Can you go when you want to go and can you keep it in if you want to keep it in?”

• “Can you stop mid-stream if you want to?” “If someone knocked on the door while you were weeing, could you stop mid flow?”

Finally, Sensation.

Fewer "I'm full!" signals mean someone with CES might not feel the urge to urinate, or feel the urge less frequently (as is clear by now, frequency, flow and sensation are all inter-related). They might also notice that urinating doesn't feel like it normally does... Perhaps it just feels funny, or perhaps they can't feel it coming out at all so that they only know they're going because they can see it coming out or hear it hitting the water. Similarly, they might not know they've finished urinating without looking or hearing that they have.

Here are some questions about bladder sensation:

• “Can you feel when your bladder is full?”

• “Do you still feel the urge to urinate?”

• “When you go for a wee, does it feel normal? Can you feel it coming out?” “Do you know when you're going?”

• “When you urinate, do you know when you’ve finished?”

So there you are—Frequency, Flow and Sensation. Together, they make up the acronym FFS, as in, “FFS, not another case of potential CES”. A hopefully fairly simple way to understand bladder dysfunction in incomplete CES.

Finally, I know you know this, but I do feel like I have to say it because otherwise I WILL get emails… the presence of bladder dysfunction alone doesn’t necessitate a trip to A&E! It all depends on how long it’s been going on, how marked the change is, whether there’s anything else to explain it, whether it’s getting better or worse, etc. etc. The big picture, basically :) Especially when we cast a wide net to catch these more subtle earlier signs, we’re bound to catch a lot of red herrings too!

Okay, that’s about it for today… I was planning to write about the all important non-CES causes of bladder dysfunction (UTIs, medications, benign prostatic hyperplasia, prolapses, stress incontinence, the body’s response to pain…), but baby Hannah is waking up, so I'd better leave that til another time.

Tom

P.S. As ever, corrections, disagreements, differing perspectives welcome… Keen to hear your experiences, too!