Blood in the urine (hematuria) is a concerning symptom that prompts many people to seek answers about its origin. Diverticulitis, the inflammation of small, bulging pouches (diverticula) in the colon wall, is primarily a digestive condition. While the two conditions seem unrelated, diverticulitis can, in rare instances, lead to urinary symptoms. This connection results from a specific, severe complication arising from the intestinal inflammation.
Understanding Diverticular Disease and Location
Diverticulosis is the presence of these small pouches, or diverticula, which commonly form in the lower part of the large intestine, known as the sigmoid colon. The condition is common, especially after age 50, and most people with diverticulosis never experience symptoms. Diverticulitis occurs when one or more of these pouches become infected or inflamed, often causing pain in the lower left abdomen.
The anatomical proximity of the sigmoid colon to the urinary bladder in the pelvic cavity creates the potential for urinary issues. The sigmoid colon typically loops downward, lying close to or directly in front of the bladder, especially in males. This close relationship means that severe inflammation or infection from the colon can affect the wall of the nearby bladder.
In females, the uterus often sits between the sigmoid colon and the bladder, offering a degree of separation. However, the inflammatory process is still close enough that a complication can bridge the two organs.
The Mechanism of Connection: Colovesical Fistulas
The specific complication linking diverticulitis to blood in the urine is the formation of a colovesical fistula. A fistula is an abnormal connection that develops between two surfaces, in this case, the inflamed colon and the bladder. This condition is uncommon, but diverticular disease causes over two-thirds of colovesical fistula cases.
When the infection in the diverticulum erodes through the colon wall, it can attach to and breach the bladder wall due to the close anatomical relationship. This abnormal channel allows contents from the colon to leak directly into the bladder. Blood from the inflamed tissue, along with bacteria and gas, enters the urinary tract, causing symptoms.
Hematuria is one symptom of a colovesical fistula. However, two other symptoms are more specific indicators of this complication: pneumaturia (the passage of gas or air bubbles in the urine) and fecaluria (the passage of fecal matter or cloudiness in the urine). A colovesical fistula is a serious condition that usually requires surgical intervention to resect the involved bowel segment and repair the defect in the bladder.
Other Common Causes of Blood in Urine
While a colovesical fistula provides the direct link between diverticulitis and hematuria, it is important to remember that it is a rare complication. The vast majority of cases of blood in the urine are caused by other, more common conditions affecting the urinary tract itself. Urinary tract infections (UTIs) are a frequent cause, as the presence of bacteria can irritate the lining of the bladder and urethra, leading to bleeding.
Kidney stones, which are hard deposits of minerals and salts, can also cause hematuria as they move through the urinary system. The stones can scrape against the delicate lining of the ureters or bladder, causing visible or microscopic blood to appear in the urine. Certain medications, strenuous exercise, and kidney diseases like glomerulonephritis are additional causes of hematuria.
In older men, an enlarged prostate, or benign prostatic hyperplasia (BPH), can also be a source of hematuria. The enlarged gland can compress the urethra and increase pressure on the bladder, leading to bleeding. Due to the range of possible causes, the appearance of blood in the urine should always prompt a medical evaluation to determine the specific source.
Diagnostic Steps and When to Seek Help
If a patient with a history of diverticulitis presents with hematuria, the diagnostic process aims to confirm the blood’s presence and pinpoint the cause, specifically checking for a fistula. The initial step is typically a urinalysis, which confirms the presence of red blood cells and checks for signs of infection, helping to rule out a simple UTI.
If a fistula is suspected, a computed tomography (CT) scan with intravenous contrast is the primary imaging test. This scan can often visualize the connection between the colon and the bladder, showing signs like air in the bladder or thickening of the adjacent bladder wall. A cystoscopy, where a flexible tube with a camera is inserted into the bladder, may also be performed to look for inflammation or the fistula opening itself.
Any unexplained blood in the urine, whether visible or detected microscopically, requires prompt attention from a healthcare provider. While diverticulitis is a rare cause, the potential for a serious complication like a colovesical fistula means that this symptom should not be ignored. Seeking medical help allows for a timely diagnosis and appropriate treatment.