The bladder is a hollow, muscular organ that collects and stores urine. Urine is produced in the kidneys and travels down to the bladder via tubes called ureters. The bladder is from inside lined with a special mucous membrane, the urothelium. This mucosa is also found in the renal pelvis, ureters and urethra. A significant absorption of liquid or urea in the bladder does not occur. It lies to some extent protected in the pelvis. Through the urethra, the urine can be drained to the outside. The bladder has two sphincter muscles. The internal sphincter is located at the outlet from the bladder and can not be influenced arbitrarily. The outer sphincter is a ring around the urethra and is consciously controlled.
The bladder of the adult has a maximum capacity of about 1000 ml, however a strong urge to urinate occurs much earlier. The urinary bladder usually holds in men 400-600 ml, in women 300-500 ml, but these values vary widely.
Through dilating sensors in the bladder wall, the filling state of the bladder is transmited to the central nervous system. The first switch point is located in the spinal cord (parasympathetic). he so-called voiding reflex is also triggered here, which induces the simultaneous contraction of the bladder muscle and relaxation of the internal sphincter muscle. From the brain the external sphincter muscle is controlled consciously. Only when this also relaxes, the urination begins.
Anatomy of female bladder; mod. nach H. Gray: Anatomy of the Human Body
Anatomy of male bladder; mod. nach H. Gray: Anatomy of the Human Body
Various imaging tests may be performed. Intravenous pyelogram (IVP) is the standard imaging test for bladder cancer. Other imaging tests include CT scan, MRI scan, and ultrasound.
Ultrasoung - detects residual urine, stones, malformation of the bladder wall (eg tumors, diverticula)
cystogram, voiding cysturethrogram - filling the bladder with a radiocontrast agent
cystoscopy (flexible and rigid instruments)
Fluorescence cystoscopy / Photodynamic diagnosis (PDD): Photodynamic diagnosis aims to improve the visualization of bladder tumours. A photosensitive compound is introduced into the bladder before a cystoscopy is performed under violet light.The tumour tissue fluoresces bright red under violet light (see picture). It improves the visualization of bladder tumours allowing more complete removal. PDD is recommended by the EAU guidlines.
With a (video) urodynamic the function of the bladder and sphincter muscle is checked-up. It is used to detect and distinguish the different disturbance of micturition (see incontinence).
a bladder tumor in a normal cystoscopy and under a blue-light cystoscopy
The most common disease of the urinary bladder is the inflammation (cystitis). Through an ascending infection across the urethra it comes to an inflammation of the bladder wall. Women are more affected due to their shorter urethra. In addition, there is often a special sensitivity (disposition) in some people. Then it comes over and over again to recurrent infections.
Overactive bladder (OAB)
The overactive bladder causes frequent urination without an adequate urine volume in the bladder.
The inability to control urination arbitrary (involuntary loss of urine) can have various causes. (See incontinence)
Vesical diverticula are outgrowths of the mucous membrane through gaps in the musculature of the bladder. They may be congenital. More commonly, they occur by hindrance of urination due to stenosis in the urethra or by an enlarged prostate. Since diverticula don’t have any muscular coverage, they do not participate in the active bladder emptying. In them develop often stones and inflammation.
The bladder rupture is usually a result of trauma of the filled bladder.
Bladder cancer is one of the more common forms of cancer and is the most common malignancy of the urinary tract. In Germany, approximately 16 000 people are diagnosed with this disease each year. It is 2 to 3 times more common in men. Bladder cancer is the fourth most common type of cancer in men and the tenth most common type in women. The incidence of bladder cancer increases with age. More than 95% of cases originate in the transitional epithelial cells (called transitional cell carcinoma; TCC). Rare types are squamous cell or adenocarcinoma.
Causes and Risk Factors
About 50 different cancer-causing agents (carcinogens) have been associatet with the devolpment of bladder cancer. Exposure to carcinogens in the workplace may increas the risk for bladder cancer. Occupational risk factors include recurrent and early exposure to hair dye, exposure to dye containing aniline, a chemical used in medical and industrial dyes. It can however take up to 40 years until the outbreak of the disease. A major cause for bladder cancer is smoking. Other known risk factors include: age, chronic bladder inflammation, external beam radiation, certain drugs (eg cyclophosphamide, phenacetin).
Signs and Symptoms
The primary symptom of bladder cancer is blood in the urine (hematuria). Hematuria is usually painless and may be visible (gross) or visible only under a microscope (microscopic). Occasionally, frequent urination, with only small portions of urine, may be present. But these symptoms can also occur in other (benign) disorders of the urinary bladder (eg inflammation). Bladder cancer must be ruled out in any patient who develops gross, painless hematuria.
In general, tumor stage is confined to one of two categories: superficial, surface tumors (affect only the bladder lining), or invasive, deep-spreading tumors. The grade depends on the loss of cellular differention. There is a strong correlation between tumor stage and tumor grade. If bladder cancer is suspected usually a cystoscopy (if possible fluorescence cystoscopy) is performed. The cystoscopy (if possible, with PDD) is usually combined with a removal of the affected area (TUR-bladder). By the superficial forms of cancer this diagnostic procedure corresponds also at the same time to the required therapy. The cases in which the tumor invades into the muscular layers of the bladder need however further therapy. Due to the aggressiveness of these tumors, this is usually in the removal of the bladder with a urinary diversion (neobladder, pouch, conduit, cutaneous ureter).
By superficial bladder cancer recurrence may be reduced through a relapse prophylaxis with irrigation/lavage of the bladder (as instillation chemotherapy or immunotherapy). Which substance comes into question depends among other things upon factors including the type of tumor.