Complexity of Urinary Tract Endometriosis: Highlights from a Review

This review paper by Nezhat et al. offers a descriptive yet succinct overview of the recent understanding of the pathogenesis, presentation, diagnosis, and clinical management of urinary tract endometriosis.

Key Points

Highlights:

• Treatment of urinary tract endometriosis requires a skilled group of physicians including urologists, surgeons, and gynecologists to plan an appropriate medical and surgical management based on the type, location, and severity of endometriotic lesions.
• Laparoscopic approaches in the management of ureteral endometriosis lessen post-surgical hospital recovery time, narcotic use, and blood loss in the hands of trained minimally invasive surgeons or urologists.

Importance:

• Effective evaluation, assessment, and management of urinary tract endometriosis are often lacking, owing to the under-reported rates in recently reported studies.
• Distinguishing the clinical signs of ureteral endometriosis is difficult given the fact that most cases are clinically silent until, in a small number of cases, hydro-ureter leads to silent kidney loss.

Key Results:

• Several theories explaining the origin and progression of endometriosis have been postulated; ranging from the retrograde menstruation theory to explain the tendency of distal ureter involvement to others that highlight the different genetic, immunologic, and pathogenic differences that characterize superficial and deeply infiltrating endometriosis.
• Early diagnosis of ureteral endometriosis is difficult since many cases present vague symptoms such as pelvic or back pain.
• Two types of ureteral endometriosis can occur: Extrinsic: most commonly caused by fibrosis external to the ureter; or intrinsic (only in minority of cases): involves the ureteral wall and at times, invades its deeper layers.
• The only way to diagnose intrinsic ureteral endometriosis is a biopsy and histopathological evaluation. Imaging modalities utilizing CT, MRI, Ultrasonography are limited in their ability to distinguish intrinsic and extrinsic ureteral disease.
• Authors suggest treating extrinsic ureteral endometriosis via ureterolysis accompanied by hydro-dissection to prevent surgical injury. The intrinsic disease may require resection of the affected area.
• Bladder endometriosis is usually symptomatic, presenting with hematuria (presence of red blood cells in the urine), suprapubic pain, and increased urinary frequency. Unlike ureteral endometriosis, ultrasonography and MRI are able to detect bladder endometriosis and should be performed if a surgical intervention is considered for optimal outcome.
• Medical therapy such as GnRH analogs is considered a temporary treatment for most bladder endometriosis. Authors explain that endometriosis on the superficial surface of the bladder is usually treated with simple excision or fulguration.
• Segmental resection of bladder endometriosis is associated with better symptom relief and decreased the chance of progression based on the author’s experiences. In cases with pelvic nerve involvement, alternative nerve-sparing surgical techniques are warranted to reduce the chance of postoperative complications.

What’s done here?

• This review paper by Nezhat et al. offers a descriptive yet succinct overview of the recent understanding of the pathogenesis, presentation, diagnosis, and clinical management of urinary tract endometriosis.

Lay Summary

Understanding the Clinical Complexity of Urinary Tract Endometriosis: Highlights from a Review

While endometriosis predominantly affects the pelvic reproductive organs, spread to the urinary tract has also been observed and requires a different subset of surgical techniques for treatment. Accurate assessment and evaluation of the extent and location of these urinary tract lesions are critical to prevent further progression of the disease.

In a recently published review paper in NatureReviews Urology, Nazhat et al. offer a summary of the recent understanding in the pathogenesis of urinary tract endometriosis and highlight from their own experience the distinguishing characteristics of its diagnosis and clinical management.

Several theories explaining the origin and progression of endometriosis have been theorized; ranging from the retrograde menstruation theory to explain the tendency of distal ureter involvement to other theories that highlight the genetic, immunologic, and pathogenic differences that explain the clinical variability of endometriosis.

Heritability of the disease is supported by twin studies that showed a significant genetic contribution to the progression of the disease and genome-wide association studies that further support several associated genetic variants. Furthermore, an association between a higher incidence of endometriosis and other autoimmune disorders has been reported.

Authors highlight that spread of endometriosis to the outer or inner layers of the ureter and bladder present themselves differently. While bladder involvement is usually symptomatic, ureteral endometriosis is for the most part silent. Diagnosis of ureteral endometriosis using ultrasonography and other imaging methods is often difficult to accomplish but authors note that intravenous pyelogram (IVP), a form of x-ray test, is often used in their practice to determine the location and degree of disease involvement. However, the diagnosis of bladder endometriosis may reliably be achieved by ultrasonography and is necessary for the postoperative success & outcome of the surgical intervention. In both cases, a biopsy must be done to confirm the presence of endometriosis.

While medical treatment is often initiated in the setting of endometriosis using GnRH agonists, combined oral contraceptives, and progestational agents, these therapies are usually beneficial only for short term. Authors recommend trained surgical endometriosis specialist that is experienced in the various laparoscopic surgical approaches and used to treat different forms of urinary tract endometriosis for successful treatment of urinary tract endometriosis.

For instance, the surgical approach used by the authors in the treatment of intrinsic and extrinsic ureteral endometriosis differs and usually involves laparoscopic ureterolysis with hydrodissection or resection, respectively. For the treatment of bladder endometriosis, authors note that in their practice, laparoscopic segmental resection of the bladder achieves the most symptom relief and lowers the risk of progression and recurrence. In cases of deeply infiltrating endometriosis (DIE), medical management is often unsuccessful and frequently requires surgical intervention especially if the pelvic nerves are involved. In these cases, laparoscopic nerve-sparing surgery should be considered as it has been seen to significantly reduce the risk of postoperative neurologic pelvic dysfunction.

Reference:

Nezhat, C., Falik, R., McKinney, S., & King, L. P. (2017). Pathophysiology and management of urinary tract endometriosis. Nature Reviews Urology.