Bladder and the Bowel

Humans require water and food to survive, and the body needs to store and then rid itself of waste products, hence the importance of the urinary bladder and the bowel. The bladder and the bowel have parallel functions, the bladder to store and release liquid waste and the bowel to store and release solid waste. Often taken for granted, the bladder and bowel become most appreciated when their function goes awry – giving rise to distressing problems that may include difficulty emptying, inability to empty, urgency, frequency, and leakage of their contents.

The bladder and the bowel have the same embryological origin. During the fourth week of embryological development the urogenital septum divides the cloaca into the urogenital sinus anteriorly (towards the abdomen) and the rectum posteriorly (towards the back).

The bladder and bowel are powerful dynamic storage units with smooth muscle content that allows for elasticity and contraction. They are smart and sensate organs with an exquisite ability to sense stretch. The often-disparaged –but vital — anus is astute enough to be able to distinguish between air, liquid, and solid. The bladder and bowel do not exist in isolation as they are connected to the nervous system and brain, are supported by connective tissue and pelvic floor muscles, and their storage function is predicated on similarly structured and functioning sphincter muscles.

The bladder and bowel can be thought of as next-door neighbors living on a cul-de-sac. This close geographic relationship facilitates interactions between the two organ systems. They most often work together collegially and at times synchronously, but this neighborly relationship can also foster discord in one system when the function of the other system is disturbed. Complicating the issue in females is the fact that there are three neighbors living on the cul-de-sac: bladder, bowel, and vagina. What happens with one neighbor can profoundly affect the others, e.g., the effect of a fibroid uterus on bladder function or when sexual intercourse causes a urinary infection, commonly referred to as “honeymoon cystitis.”

The bladder and bowel demonstrate cross organ sensitization, a phenomenon in which symptoms in one organ are related to distention or inflammation of the other. Bladder-colon cross sensitization is bidirectional and urinary disorders are correlated with defecatory disorders and treating one system may affect (improve or worsen) the function of the other system. In general, the effects of colonic issues on bladder function are generally more substantial than the effects of bladder issues on colonic function.

The most common example of bladder-bowel cross sensitization is constipation, which can profoundly adversely affect urination, typically resulting in difficulty urinating, at times the inability to urinate, and at other times overflow urinary incontinence. Urology consultation is often called for when an elderly person in a nursing home has not moved their bowels for a week or so and subsequently cannot urinate. As is often the case, the treatment of the urinary issue is to manage the bowel issue.  When the bowel is distended with gas, it can compress upon the bladder causing a false sense of urgency to urinate. Likewise, bladder fullness can cause bowel urgency. Fecal and urinary incontinence often occur in concert.

Other examples of bladder-bowel cross sensitization include the following:

–> The condition of pelvic floor hypertonicity in which the pelvic floor muscles are taut and fail to relax properly will often affect both bladder and bowel adversely.

–> Hyperactive function can affect both bladder and bowel: these conditions are labeled overactive bladder and irritable bowel syndrome, respectively.

–> Treatment of overactive bladder with anticholinergic medications can cause constipation.

–>Hypoactive function can affect both bladder and bowel: these conditions are labeled under-active or poorly contractile bladder and under-active bowel (constipation), respectively.

–> Psychological stress is often internalized and can manifest via the powerful mind-body connection with bladder and/or bowel symptoms, typically urinary and/or bowel urgency and frequency.

–> Treatment of bladder infections with antibiotics can cause diarrhea from C. Difficile colitis.

–> Constipation and chronic straining can lead to bladder prolapse and stress urinary incontinence.

–> An important component of the management of many issues involving the bladder and bowel are pelvic floor exercises (Kegel exercises) that can be used to effectively quiet bladder and bowel urgency.

Sound advice for optimizing bladder and bowel function is a healthy, largely plant-based diet with lots of fiber, maintaining a state of good hydration, and staying physically active. What’s good for the bowel is good for the bladder and vice-versa.