Pressure on or in the bladder can occur for several reasons. Sometimes this is just due to the normal filling of the bladder with urine while at other times there may be a problem with emptying of urine resulting in overfilling. Pressure on the bladder can even occur without any problem in the bladder itself, like a tumor of a surrounding organ that then presses on the bladder.
Normal Bladder Pressure Feeling
We all experience a pressure sensation in the bladder several times within a day. This is normally referred to as urging. It means that our bladder is signalling us that it needs to be emptied. As time passes this urging gets more intense. As the bladder is emptied the pressure feeling (urging) gradually subsides. It eventually returns once the bladder fills again with urine.
The urinary bladder is a muscular organ. It can expand and shrink depending on the volume of urine within it. Urine is produced by the kidneys, passed down the ureters on either side and stored within the bladder. It is produced throughout the day and night as the kidneys filter the blood of wastes, toxins, excess nutrients and water. Gradually the bladder fills with urine.
Read more on bladder control.
The filling of the bladder causes its muscular walls to stretch. Initially there may be little or no sensation due to this filling. As the bladder fills further, the expanding of the bladder stimulate stretch receptors in the bladder wall. It is the impulses generated by the stimulation of the stretch receptors that give rise to the pressure sensation in the bladder. It is a type of monitoring system that notifies the body about the degree of bladder filling.
Th eurinary bladder has a capacity of about 400mL to 500mL (approximately 13 to 16 ounces). It can be larger and stretch even further up to 600mL (20 ounces) in some people. Most of the time we feel a strong urge to urinate once the bladder fills but is not overly stretched. This urge is uncomfortable. When severely stretched, the pressure can be extremely uncomfortable.
Abnormal Bladder Pressure Sensation
Pressure in the bladder is naturally considered to be urging to pass urine. Everybody is accustomed to this sensation and it is normal. However, if the bladder is not full of urine or is the sensation does not subside even after passing urine, then it has to be considered abnormal. This may also be described as incomplete emptying or persistent urging to urinate. Another term that may be used is vesical tenesmus or urinary tenesmus. All of these terms and descriptions refer to an ongoing pressure sensation in the bladder.
Read more on bladder fullness.
Bladder infections are one of the more common causes of this abnormal pressure sensation in the bladder. Most bladder infections are due to bacteria that enter the through the urethra. This is known as an ascending infections as the it passes upwards from the urethra to the bladder. Infectious cystitis, another term for a bladder infection, is more common among women than men, due to the shorter urethra in females.
Bladder injury may arise for several reasons beyond just infections. It can occur with a blow to the pelvis as may seen with a motor vehicle collision, contact sport injury or assault. Trauma may also arise with certan medical procedures like with the insertion of a urinary catheter or surgery to pelvis and perineum. Radiation as part of cancer treatment and chemicals that may enter through the genitalia can also injure the bladder.
Inflammation of the bladder can occur for various reasons other than infections and trauma mentioned above. Allergies are one such instance. This may arise when certain substances, other than infectious agents, gain entry to the bladder and trigger an immune reaction. These substances are usually harmless. It includes substances such as soaps, feminine sprays and lubricant or spermicidal jellies. Some drugs can also irritate the bladder.
Stones in the bladder may form in the kidney and pass down into the bladder or may originate within the bladder. These stones can occupy space and reduce the capacity of the bladder to store urine. It also can block the bladder outlet thereby preventing or impairing the emptying of the bladder. In addition, bladder stones may injure the bladder wall especially when these stones have spiky or jagged edges.
Bladder tumors can be malignant (cancerous) or benign (non-cancerous). Benign tumors can reduce the bladder capacity as well as compress nerves in the bladder which may hamper bladder emptying. Bladder cancer is one of the more common types of cancer and damages the muscle wall, nerves and other structures of the bladder. Cancer from neighboring organs such as the prostate (men), uterus (women) and rectum can also spread to the bladder.
Dysfunction of the nerves that control bladder activity can also affect bladder emptying. This is also known as neurogenic bladder. It may occur as a results of several conditions such as nervous system infections, spinal cord injury, Parkinson’s disease, stroke, diabetes mellitus, spinal nerve root compression, brain and spinal cord tumors, alcohol abuse, nutritional deficiencies and other conditions.
Several conditions that affect the bladder muscles can cause disturbances with bladder emptying. Muscles do not only make up the bladder wall. It also controls valves that allows urine to pass out of the bladder and into the urethra to be expelled into the environment. One such condition is overactive bladder where the bladder muscles contract involuntarily. However, it is not always due to a muscle problem and can arise with nerve disorders.
The prostate lies immediately below the bladder in males. The urethra that carries urine out of the bladder passes through the prostate gland. Problems with the prostate can therefore impact on the bladder. An inflamed or enlarged prostate can press against the bladder. It can also narrow the urethra thereby hampering the outflow of urine. Tumors of the prostate gland can also push against the bladder and even invade bladder tissue.
The colon and rectum lie behind the bladder and conditions affecting these organs can also impair bladder emptying. Apart from benign tumors and cancer discussed above, constipation is another factor to consider. Stool collects in the colon and rectum thereby pressing against the bladder. This is more likely to occur with fecal impaction where the stool becomes hard and cannot be pushed out of the colon and rectum.
The pregnant uterus increases pressure within the lower abdomen and pelvis. It often presses against the bladder which can cause a persistent pressure sensation. It is one of the reasons that pregnant women may experience the need to urinate frequently despite passing out small amounts of urine. In addition the high levels of pregnancy hormones may also alter normal bladder function to some degree.