A bladder diverticulum is a pouch that forms when the inner lining of the bladder bulges outwards through a weakness in the muscular layer. While small diverticula often cause no symptoms, they are not always harmless. These pouches can trap urine, potentially leading to serious health issues if left unaddressed.
Defining Bladder Diverticulum
A bladder diverticulum forms when the inner lining (urothelium) pushes through defects in the detrusor muscle fibers of the bladder wall. This protrusion creates a sac-like structure connected to the main bladder cavity by a neck. The two primary types are congenital and acquired.
Congenital diverticula are present from birth, often appearing as a single pouch due to a developmental weakness. Acquired diverticula are far more common, developing later in life due to chronically increased pressure within the bladder. This high pressure usually results from a bladder outlet obstruction, such as an enlarged prostate or a urethral stricture. The acquired form often lacks a muscle layer, making it a pseudodiverticulum, and may involve multiple pouches.
Primary Health Risks and Complications
The main danger associated with a bladder diverticulum is that it often empties poorly during urination, leading to urinary stasis. This trapped, residual urine pools and stagnates in the pouch, creating an ideal environment for bacteria to multiply. This frequently results in chronic urinary tract infections (UTIs) that are difficult to clear because antibiotics struggle to reach therapeutic concentrations within the poorly emptied sac.
The stagnant urine also allows minerals to precipitate and build up, resulting in the formation of bladder stones within the diverticulum. These stones can cause pain, bleeding, and further obstruction. While rare, there is a slightly increased risk of developing urothelial carcinoma (cancer) within the diverticulum. This risk is higher because the pouch’s thin wall lacks the protective muscle layer, and chronic irritation from infection and stasis may contribute to malignant change.
Recognizable Symptoms and Diagnosis
Bladder diverticula often do not cause specific symptoms and may be discovered incidentally during imaging for unrelated conditions. When symptoms do appear, they are usually related to complications from trapped urine. Common signs include frequent urination, pain or burning during urination (dysuria), a sensation of incomplete bladder emptying, or blood in the urine (hematuria).
Diagnosis often begins with an ultrasound, which uses sound waves to visualize the bladder and show the presence of a pouch. Further evaluation may involve a CT scan or a cystogram, an X-ray performed after contrast dye is placed into the bladder. A cystoscopy, where a small camera is inserted through the urethra, allows the doctor to visually inspect the diverticulum’s opening and check for stones or suspicious lesions.
Treatment and Management Options
The decision to treat a bladder diverticulum depends heavily on its size and whether it is causing symptoms or complications. Small diverticula that are not causing recurrent infections, stones, or significant urinary retention may simply be monitored through watchful waiting. This surveillance typically involves regular check-ups and imaging to ensure the pouch is not enlarging or developing new problems.
For large diverticula or those causing recurrent UTIs, stones, or cancer risk, surgical intervention is generally recommended. The procedure to remove the pouch is called a diverticulectomy, which can be performed through traditional open surgery or minimally invasive techniques like laparoscopy or robotic surgery. For acquired diverticula, it is also necessary to address the underlying cause of the high bladder pressure, such as treating an enlarged prostate, to prevent new pouches from forming.