Pelvic Organ Prolapse and Recurrent UTIs

Pelvic Organ Prolapse and Recurrent UTIs could be connected but the relationship is much more complicated than you might think.

As you know, urinary tract infections (UTIs) are very common, affecting nearly 40 percent of women over the course of their lifetime (1). 

As to pelvic organ prolapse (POP), it involves having the uterus, bladder, rectum, and/or soft tissue of the pelvis fall through the vagina.  It is common after vaginal deliveries. 

Do You Have Pelvic Organ Prolapse?

Interesting fact, the number of women who have symptoms of POP is only about 3-6 percent. However, nearly 50 percent discover that they have POP during gynecological evaluation through a pelvic examination. Not surprisingly, surgery for prolapse is twice more common as incontinence surgery with a prevalence of about 6 to 18 percent (2).

Recurrent UTIs can be defined as 2-4 UTIs in the previous year.  The most common risk factors for UTI and recurrent UTI include sexual intercourse (particularly with a recent new partner), family history, contraceptive use (including the diaphragm, IUD, spermicides, and birth control pills), and the urethro-anal distance (the space between the urethra and the anal opening, where the UTI bacteria come from.  Women who do not secrete the ABO blood group antigens have a four-fold increase in recurrent UTIs versus secretors.  The content of the vaginal flora also seems to play a role in getting recurrent UTIs (1).   

If you do have symptoms of POP you may experience:

  • Some will experience sexual dysfunction,
  • The sensation of a lump or fullness in the vagina,
  • Issues with emptying bladder or urine leaks,
  • Or bowel dysfunction. 
  • A few women will have recurrent UTIs as their only presenting concern (1). 

UTI and POP: Is There a Link?

Studies have been done on the risk factors of recurrent UTI and POP, including a 2009 study by Haylen et al—a prospective observational study of 1,140 women with symptoms of pelvic floor dysfunction (3).  Contrary to expectations, never having given birth was most associated with recurrent UTIs as well as having a post-void residual (PVR) of greater than 30 milliliters.

There are several factors that could be protecting a woman who has been pregnant and delivered: 

  • The number of sexual partners may decrease in a woman who has children, and there is a known link between the number of sexual partners and recurrent UTIs. 
  • The relaxation and stretching of the vaginal vault may decrease friction, which may be another cause of UTI in sexually active women. 

The Haylen paper found no specific link between urinary tract infections and POP.  In fact, there was a negative association between high-grade POP and recurrent UTIs.  There is, however, a connection between POP and voiding dysfunction, which was not translated into recurrent UTIs in the Haylen study. 

POP Surgery And UTI

The link between POP and UTIs comes into play when a woman has surgery for POP or for stress urinary incontinence (SUI). 

The prevalence of POP and stress urinary incontinence is so high that around 11 percent of women will have surgery for these conditions at some point in their lives.  Among women who had autologous sling surgery for incontinence problems, nearly half of all women had a postoperative UTI within two years after surgery (4). Another study revealed that a third of all women have a UTI within three months of their surgical procedure. 

The risk factors for UTI after POP and SUI surgery included:

  • Incomplete bladder emptying postoperatively
  • And transurethral catheterization at the time of surgery or as a method of managing voiding dysfunction. 

Since the bladder’s main defense system against the development of a UTI involves the ability to empty itself, everything that interferes with this function can adversely affect your chances to develop a UTI. 

Urinary retention postoperatively can be caused by:

  • interruption of nerve connections interfering with bladder functions, 
  • postoperative swelling of the vaginal and bladder tissues,
  • anesthesia side-effects,
  • poor vascularization of tissues,
  • and the use of opioids, which naturally cause urinary retention and constipation.

Unfortunately, prophylactic antibiotics do not seem to help reduce the incidence of postoperative UTI.

POP, UAD & UTI

An interesting study was performed by Sutkin et al. They evaluated the urethral anal distance (UAD) and found that, in fact, the greater the UAD, the greater the risk of UTI.  There have been theories that a shorter AUD predicts UTI because of the shorter distance between the urethra and anus, the source of bacteria causing UTIs. What was proposed in the study, however, was that an increase UAD was a marker for compromise of the pelvic floor neurological and muscular function in the pelvic floor—a risk factor for pelvic organ prolapse. Those who have prolapse surgery continue to have pelvic floor dysfunction and an increased UTI risk (5).

Pelvic organ prolapse is sometimes linked to an increased post-residual volume, which is a clear risk factor for recurrent UTI.  While repairing the prolapse will usually be successful in reducing the PVR, there will still be large-scale pelvic floor dysfunction, which may mean that the surgical reduction and repair of prolapse won’t necessarily be helpful in preventing recurrent UTI. 

POP, PVR & UTI

Another study (4), looked at the incidence of coexisting POP and recurrent UTI.  A total of 105 women were evaluated as outpatients, having stages II-IV vaginal prolapse, including cystocele or cystorectocele, descensus uteri, and symptomatic urinary incontinence. The POP-Q system was used to quantify the degree of prolapse. The group was compared to a control group without POP.

There was no statistical association between POP and the occurrence of recurrent UTI.  The number of women in the prolapse group that had recurrent UTI was 21 percent versus an incidence of UTI of 18 percent in the control group. The PVR was measured in each woman.  Eighteen percent of patients with POP had a PVR of greater than 50 ml, which is a risk factor for recurrent UTI. In fact, of the 19 women with PVR volumes of greater than 50 ml, 16 of these women had a history of recurrent UTI. Only six of 86 women with PVR volumes of less than 50 ml had recurrent UTI in the study group. 

In the control group, 93 percent of participants had PVR volumes of less than 50 ml, with 7 percent having a PVR volume of greater than 50 ml. In this group (without POP), there was no relationship between PVR volume and the prevalence of recurrent UTI. 

What this means is that, while having POP doesn’t necessarily increase the recorded prevalence of UTI, it does indirectly affect the recurrent UTI rate by causing an increase in the PVR volume. There are clear distortions of the lower urinary tract structures with POP that lead to an increased risk for elevated PVR volumes and an increased risk of recurrent UTI in those who have this phenomenon. 

By distorting the lower urinary tract structures, POP causes an increased risk of urethral obstruction, decreased urine flow rates, voiding problems, and increased PVR volumes.  The PVR volume can be indirectly measured with a transvaginal ultrasound, making it a noninvasive way of evaluating urinary complaints in women with POP.

Postoperative UTIs after POP Repair Surgery

There is a clear increase in UTIs after POP repair surgery among women who have negative urine cultures on the day of surgery.  There is evidence to suggest that the bladder is not a completely sterile environment and that it has a urinary microbiome that isn’t detected on standard cultures and that is kept in check by the innate immune system (6). 

Researchers have been able to detect the presence of a urinary bladder microbiome using DNA sequencing. In fact, the presence of certain bacterial species in the urine on the day of surgery can predict who will get a postoperative UTI after POP/UI surgery. The identification of these high-risk women through DNA sequencing may not yet be something done in clinical practice; however, this technique can be used to plan interventional clinical trials attempting to prevent or better manage these symptomatic postoperative UTIs.

In the study (6), published in 2014, women having POP/UI surgery had catheter-obtained urine cultures taken under anesthesia on the day of surgery. Twenty-four percent had positive cultures from this evaluation. About 18 percent of the women developed urinary symptoms after surgery with 7 percent having positive postop cultures.

There was a significant difference in the urinary microbiota on the day of surgery among women who developed a postoperative UTI compared those who did not have UTI symptoms. With sensitive DNA sequencing techniques, it was found that urine consistently contains a specific living microbiota that likely creates a protective environment against pathogen invasion. 

Bladder Microbiome and POP Surgery

Women with POP specifically have a different bladder microenvironment when compared to women without POP. Women with a diverse bladder microbiota have greater protection against UTI versus women who have a dominant-species microbiota.

POP appears to generate a group of women who have an overgrowth of specific bacteria that act as markers for UTI postoperatively.  Those species include Escherichia, Shigella, Klebsiella, and Pseudomonas, which exist as a dominant part of the microbiota of the bladder. This dominance increases the risk of postoperative infections among women who have POP surgery.

As mentioned, many of these organisms do not necessarily grow out in a day-of-surgery urine culture but are measured through DNA sequencing. As this isn’t available in clinical usage, there remains an unknown as to who is at an increased risk of UTI after POP surgery. The possibility of doing extended cultures exist as well as re-identifying positive cultures as having fewer colony forming units than is currently the case. A single entity growing out in small numbers may be clinically significant and can identify those individuals who might require increased surveillance after their POP/UI surgery.

References

  1. Hamid R and Losco G. Pelvic Organ Prolapse-Associated Cystitis. Curr Bladder Dysfunct Rep. 2014; 9(3): 175–180.
  2. Barber MD, Maher C. Epidemiology and outcome assessment of pelvic organ prolapse. Int Urogynecol J. 2013 Nov;24(11):1783-90.
  3. Haylen B, et al. Recurrent urinary tract infections in women with symptoms of pelvic floor dysfunction. Int Urogynecol J. 2009; 20:837–42.
  4. Toz E, et al. Frequency of recurrent urinary tract infection in patients with pelvic organ prolapse. Res Rep Urol. 2015; 7: 9–12.
  5. DeLancey JO, Hurd WW. Size of the urogenital hiatus in the levator ani muscles in normal women and women with pelvic organ prolapse. Obstet Gynecol. 1998; 91:364–8.
  6. Nienhous V, et al. Interplay between Bladder Microbiota and Urinary Antimicrobial Peptides: Mechanisms for Human Urinary Tract Infection Risk and Symptom Severity. PLoS One. 2014; 9(12): e114185.

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