IC and IBS: What is the relationship between the bladder and the colon?
If you have done any research on IC, you are probably aware that a large proportion of IC patients also have IBS. About 33% actually1. That’s much higher than the expected rates of 10-15%2 that affect the general adult population in the US.
But why? And how can we use this knowledge to control our IC symptoms?
Let’s start with the physiology. Then we will look at how we can incorporate this knowledge into our own self-treatment protocols.
The Physiology behind why your bladder and your bowel act like BFFs
Three words: Cross organ sensitivity. It has been demonstrated that pathological changes in one system can induce the development of cross-organ sensitization in the pelvis. This may explain the clinical relationship of genitourinary and GI dysfunctions.
Proper functioning of the pelvis requires coordinated activities between the lower urinary tract (LUT) and the GI tract. This is due to the following:
- Close proximity
- Same embryological origin
- Shared group of supporting muscles (the pelvic floor)
- Similar functions of storage and evacuation
- Shared brain regions for processing of afferent neural impulse activity (afferent means AWAY from an organ towards the CNS (Brain and spine)
Many observational studies have shown that bladder and colorectal dysfunction often occur together. These reports demonstrate that an exacerbation of a problem in one of these systems is frequently associated with distention, irritation or inflammation of the other system.
Here is what else we know from the research:
- Studies have shown a relationship between rectal distention and bladder compliance and sensations of bladder filing4
- Rectal state significantly influences LUT sensory information and responses 4, 5
- Bladder volumes influence rectal urgency5
- In children, rectal distension unpredictably affects bladder capacity, sensation and detrusor overactivity, regardless of whether the pt is constipated6
- Fecal incontinence is associated with urinary urgency, frequency and urge incontinence7
- Dysfunction voiding and uroflow abnormalities occur more frequently in women with diagnosed with defecatory disorders7
- Women with fecal incontinence were more likely to have detrusor instability, stress incontinence or sensory urgency8
- Treating a problem in one system can improve or worsen symptoms in the other (treat constipation in kids and prevent recurrent UTIs, drugs used to treat overactive bladder cause constipation, etc)9
- Ibs patients are more likely to have bladder urgency and frequency than patients without IBS10
- There is a higher incidence of irritable bowel syndrome and other inflammatory bowel conditions in patients with IC when compared to the general population11
Here’s a bit of bad news: Studying the relationships between colon and bladder disorders in humans is difficult due to a lack of animal models for chronic or recurrent disorders like IC and IBS. However, several rodent models have recently been established to look at the application of a noxious stimulus to either organ system and the resulting mechanisms and expressions of colon-bladder cross-sensitization.
These animal-model studies found a significant correlation between acute colitis and changes in bladder contractility as well as neurogenic dysfunction marked by hyperactivity and hyperexcitability. Researchers also found that though this colon-bladder cross-sensitization is bilateral (meaning it works both ways), it is more likely to occur when the colon, via some noxious GI stimuli, negatively alters the function of the bladder.
Basically, the belly is a bully!
There are a few reasons why researchers think the colon is able to exert a stronger effect on the bladder vs the bladder impacting the colon.
- The colon’s surface area is larger with more receptors, pathways, and neurons. This means the impact of an insult would be proportionally more widespread
- The lining of the colon and bladder are different; the colon epithelium is highly absorbent to water and electrolytes while the bladder mucosa is more protective in nature and may form a more substantial barrier against noxious stimuli
Makes you wonder if we should pay less attention to our bladder and more attention to our belly!
So just how exactly is our body getting mixed up between what hurts and what should hurt? It’s sort of a pathway of confusion. If we oversimplified it, you would get something like this:
A sensory fiber innervating the bowel or bladder gets a message from the organ that some sort of bad thing happened to it. It gets excited and sensitized (sort of like when you’ve had 3 glasses of wine and get in a fight with your spouse). It then wants to let the central nervous system that “hey we got some sort of problem going on here” which leads to central sensitization in your brain and spine (the bad news spreads).
Sounds reasonable right?
But there is a problem. The afferent inputs—the messages being sent away from the bladder and colon towards the brain—not only converge onto the same primary sensory neurons, they also converge in the same place in the spine and brain.
Which means the wires get crossed. Your brain is interpreting things that are happening in one system as also happening in the other.
And this cross-sensitization is why when we are thinking about our bladders, we also need to think about our bowels. They work hard together and they play hard together. Guess we shouldn’t be surprised that there is a relationship between IBS and IC.
But more importantly, this opens up a whole other set of ideas on what triggers your IC flare, as well as creates new opportunities to improve your symptoms via lifestyle and dietary modifications. That’s actually good news.
And it makes me wonder:
Is the IC diet even about acid or is it about food intolerances and sensitivities?
Could your chronic constipation or food allergies be the thing that caused your IC symptoms?
Ready to try fixing your gut help your Interstitial Cystitis? If you’re one of the many IC patients who also have GI dysfunction, this could be key to preventing flares and managing your condition.
References for you IC nerds who like references (p.s. we love you for that):
- Malykhina, A. P., Wyndaele, J.-J., Andersson, K.-E., De Wachter, S. and Dmochowski, R. R. (2012), Do the urinary bladder and large bowel interact, in sickness or in health?: ICI-RS 2011. Neurourol. Urodyn., 31: 352–358. doi:10.1002/nau.21228
- De Wachter S, Wyndaele JJ. Impact of rectal distention on the results of evaluations of lower urinary tract sensation. J Urol. 2003;169:1392
- Panayi DC, Khullar V, DIgesu GA Spiteri M Hendricken C, Fernando R. Rectal distension: the effect on bladder function. Neurourol Urodyn., 2011;30:344
- Klingele CJ, Lightner DJ, Fletcher, JG, Gebhart JB, Bharucha AE. Dysfunctional urinary voiding in women with functional defecatory disorders. Neurogastroenterl Motil. 2019;22:1094
- Burgers R, Liem O, Canon S, Mousa H, BEnninga MA, Di Lorenzo C et al. Effect of rectal distention on lower urinary tract function in children. J Urol.2010;184:1680
- Khullar V, Damiano R Toozs-Hobson P, Cardoza L. Prevalence of fecal incontinence among women with urinary incontinence. Br J Obstet Gynecol. 1998;105:1211
- Wyndale JJ Goldsicher ER Morrow JD Gong J Tseng LJ Guan Z et al. Effects of flexible-dose fesoterodine on overactive bladder symptoms and treatment satisfaction: an open-label study. Int J Clin Pract.2009;63:560
- Monga AK, Marrero JM Stanton SL Lemieux MC Maxwell JD. Is there an irritable bladder in the irritable bowel syndrome? Br J Obstet Gynecol. 1997; 104:1409
- Alagiri M Chottiner S Ratner V Slade D Hanno PM. Interstitial Cystitis: unexplained associations with other chronic disease and pain syndromes. Urology 1997;49:52
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