Endometriosis, a condition where tissue similar to the uterine lining grows outside the uterus, can cause pain in various parts of the body. While commonly associated with pelvic discomfort, it can, in rare instances, affect the kidneys when endometrial-like tissue implants on or near the urinary system. This article explores how endometriosis can impact kidney health, its symptoms, and approaches to diagnosis and management.
How Endometriosis Can Affect the Kidneys
Endometriosis can lead to kidney pain primarily through its involvement with the ureters, the tubes that transport urine from the kidneys to the bladder. This specific manifestation is known as ureteral endometriosis, a form of deep infiltrating endometriosis. Endometrial implants can grow on the outside of the ureter, causing external compression. Less frequently, the tissue can directly penetrate the ureteral wall, known as intrinsic ureteral endometriosis.
When these endometrial implants or surrounding adhesions constrict or block the ureter, the flow of urine from the kidney is impeded. This blockage causes urine to back up and accumulate in the kidney, a condition called hydronephrosis. The swelling and increased pressure within the kidney capsule resulting from hydronephrosis directly cause kidney pain. If left unaddressed, this sustained pressure can lead to kidney damage and, in severe cases, even loss of kidney function.
The chronic inflammation associated with endometriosis also contributes to pain and potential damage. Endometrial lesions release inflammatory substances that can irritate surrounding tissues, including the ureters and kidneys. The formation of adhesions, or scar tissue, due to this inflammation can further encase and distort the ureters, exacerbating the obstruction and pain. While direct invasion of kidney tissue by endometriosis is extremely rare, ureteral involvement is the more prevalent mechanism.
Ureteral endometriosis is rare, affecting between 0.1% and 1.7% of women with endometriosis. It is more common in individuals with deep infiltrating endometriosis, affecting 20% to 52.6% of those cases. The left ureter is more frequently involved than the right, and lesions are often found in the lower third of the ureter, near the bladder.
Recognizing Symptoms and When to Seek Medical Help
Kidney pain from endometriosis often presents as a dull ache or sharp pain in the flank, the side of the body between the ribs and the hip. This pain can also radiate towards the groin. Unlike general pelvic pain associated with endometriosis, kidney pain is typically felt higher up and may be more localized to one side.
Other symptoms might accompany kidney involvement in endometriosis, including changes in urination patterns, such as increased frequency, urgency, or pain during urination (dysuria). Some individuals may notice blood in their urine (hematuria), which can sometimes be cyclic, occurring with menstrual periods. Recurrent urinary tract infections (UTIs) may also indicate an underlying issue with urine flow.
If the obstruction leads to infection, a fever might develop. Notably, nearly 50% of ureteral endometriosis cases can be asymptomatic, meaning individuals might not experience noticeable symptoms. This “silent obstruction” can lead to gradual kidney damage without overt warning signs.
Given the potential for kidney damage, it is important to address these symptoms promptly. If you experience persistent flank pain, new onset of pain in the kidney area, changes in urination, blood in your urine, or recurrent UTIs, especially if you have a known diagnosis of endometriosis, seek medical attention. Early recognition and intervention can help prevent irreversible kidney damage.
Diagnosis and Management of Kidney Involvement
Diagnosing kidney involvement in endometriosis begins with a thorough medical history and physical examination, focusing on symptoms and endometriosis history. Because symptoms can be subtle or mimic other conditions, a high level of suspicion is often necessary. Imaging studies are important for identifying ureteral obstruction and assessing kidney health.
Ultrasound is often the first-line imaging test, used to check for hydronephrosis. Magnetic Resonance Imaging (MRI) provides detailed views of soft tissues and can visualize deep infiltrating endometrial lesions that may be compressing the ureter. Computed Tomography (CT) scans are also used to assess the extent of obstruction and visualize the urinary tract. Urine tests check for infection or blood, while blood tests assess kidney function. Histopathological examination of tissue remains the definitive method for confirming endometriosis.
Management strategies aim to relieve ureteral obstruction, alleviate symptoms, and preserve kidney function. For mild cases of ureteral endometriosis, medical management with hormonal therapies, such as GnRH agonists, combined oral contraceptives, or progestins, may be considered. These treatments help suppress the growth of endometrial tissue. However, medical treatment alone may not resolve fibrosis or severe obstruction.
Surgical intervention is frequently necessary, especially in cases of significant obstruction or when medical therapies are insufficient. Surgical options include ureterolysis, which involves freeing the ureter from surrounding adhesions and endometrial implants. In more complex cases, a segment of the affected ureter may need to be resected, followed by re-implantation into the bladder or rejoining the ureter (ureteroureterostomy). Temporary placement of a ureteral stent may be used to relieve obstruction and allow the kidney to drain. Long-term follow-up is important to monitor kidney function and detect any recurrence of ureteral obstruction.