Uterine fibroids, also known as leiomyomas, are common, non-cancerous growths that develop from the muscle tissue within the wall of the uterus. While often associated with heavy menstrual bleeding and pelvic pain, these growths can also cause a range of symptoms that closely resemble a urinary tract infection (UTI). The source of these urinary problems is mechanical pressure from the fibroids rather than a bacterial infection.
Physical Mechanisms Connecting Fibroids and Urinary Issues
The uterus is positioned deep within the pelvic cavity, located directly behind the bladder, which is the organ responsible for urine storage. As fibroids grow, particularly large ones or those situated on the anterior (front) wall of the uterus, they begin to occupy the limited space shared by these organs. This anatomical proximity means that fibroid expansion directly exerts pressure onto the bladder wall.
This mechanical compression significantly reduces the bladder’s functional capacity, meaning it can hold less urine before signaling the urge to empty. The result is a constellation of symptoms often referred to as “bulk symptoms,” which include increased urinary frequency, a sudden, strong urge to urinate (urgency), and waking up multiple times at night to use the bathroom (nocturia). Fibroids can also physically distort the lower part of the bladder or the urethra. This distortion may prevent the bladder from fully emptying, leaving residual urine that can contribute to discomfort and further urinary issues.
In rare instances, extremely large fibroids can compress the ureters, which are the tubes that transport urine from the kidneys down to the bladder. This compression can cause urine to back up toward the kidneys, a serious condition called hydronephrosis. This obstruction requires prompt medical evaluation because it can potentially impair kidney function over time.
Identifying the Source of Urinary Symptoms
While fibroids and UTIs can both cause frequent urination and urgency, key qualitative differences can help distinguish between the mechanical pressure and a true bacterial infection. Urinary symptoms caused by fibroid pressure tend to be chronic and consistent, often accompanied by a general sensation of pelvic fullness or heaviness. The urgency is typically a persistent issue linked to the physical mass within the pelvis, rather than the sudden onset associated with an acute infection.
Conversely, symptoms caused by a bacterial UTI are inflammatory in nature and usually include telltale signs of infection. These often involve dysuria (a stinging or burning pain during urination), cloudy or foul-smelling urine, fever, chills, or pain in the back or side, particularly if the infection has reached the kidneys. The sensation of incomplete emptying caused by a fibroid is primarily due to physical blockage, whereas the same sensation in a UTI is often a result of bladder wall irritation.
Incomplete bladder emptying caused by fibroids can create a favorable environment for bacteria to multiply, thereby increasing the risk of developing a true bacterial UTI. Therefore, experiencing fibroid-related pressure symptoms does not eliminate the possibility of a concurrent infection.
Medical Testing to Confirm the Cause
The diagnostic process for urinary symptoms begins with confirming or ruling out a bacterial infection. A urinalysis is performed to examine the urine sample for signs of infection, such as the presence of white blood cells, nitrites, or red blood cells. If infection is suspected, a urine culture is then carried out to identify the specific type of bacteria present and determine the correct antibiotic treatment.
Once an active infection is ruled out, imaging studies are used to visualize the uterus and surrounding structures to confirm fibroids as the source of the pressure. The preferred initial test is a pelvic ultrasound, often performed both transabdominally and transvaginally. Magnetic Resonance Imaging (MRI) offers even greater detail, helping to precisely map the fibroids, particularly in relation to the bladder and ureters, which is useful for planning any potential surgical interventions. In complex cases, especially where ureter compression is suspected, a Computed Tomography (CT) scan or a specialized procedure like cystoscopy may be used to assess the upper urinary tract or the inside of the bladder.
Managing Fibroids That Affect Urinary Function
Once fibroids are confirmed to be the cause of urinary dysfunction, treatment focuses on reducing the size of the growths to relieve pressure on the bladder. For patients with mild symptoms, medical management options include hormone therapies, such as Gonadotropin-releasing hormone (GnRH) agonists, which can temporarily shrink fibroids by inducing a hypoestrogenic state. These medications are typically used to bridge a patient to menopause or as a temporary measure before a procedure.
Minimally Invasive Procedures
Minimally invasive, uterus-preserving procedures offer another pathway. Uterine Fibroid Embolization (UFE) involves injecting small particles into the arteries that supply the fibroid, cutting off its blood flow and causing it to shrink significantly, thereby alleviating bladder pressure. Magnetic Resonance-guided Focused Ultrasound Surgery (FUS) is a non-incisional option that uses high-intensity sound waves to destroy the fibroid tissue.
Surgical Options
Surgical options provide the most definitive treatment, with the choice depending heavily on the patient’s desire for future fertility. A myomectomy removes only the fibroids, leaving the uterus intact for potential future pregnancy. If fertility is no longer a concern or if the fibroids are numerous and very large, a hysterectomy (removal of the entire uterus) permanently eliminates the source of the pressure and the symptoms.