How does prostate enlargement cause frequent urination?
Prostate enlargement, or benign prostatic hyperplasia (BPH), results in frequent urination due to how the enlarged prostate affects the urinary system, i.e., the bladder and urethra. This is how the process works:
1. Prostate Anatomy and Position
Prostate gland lies just below the bladder and surrounds the urethra, the pipe from which urine goes from the bladder out of the body.
When the prostate gland becomes enlarged, it grows and presses against the urethra. This pressure can cause a narrowing or obstruction of the urethra, which disrupts the flow of urine in the usual manner.
2. Increased Frequency of Urination
As the prostate enlarges and compresses the urethra, the bladder has to contract harder to push urine out through the narrowed tube. This can make the bladder more irritable, leading to more frequent contractions and frequent emptying of the bladder.
The bladder is also less able to retain urine for long periods since the pressure from the prostate is higher. Thus, the urine is retained in smaller amounts, and one has to urinate more frequently.
3. Reduced Bladder Emptying
If the prostate gland enlarges and presses on the urethra, the bladder may fail to empty.
This is where, during urination, some amount of urine remains in the bladder, creating the feeling of incomplete emptying.
Incomplete bladder emptying can cause more frequent urination because the remaining urine acquires volume much sooner.
4. Nocturia (Nighttime Urination)
More frequent urination typically worsens at night (nocturia) because the bladder’s urine-holding capacity is decreased further when asleep. The pressure of the enlarged prostate makes it more difficult to hold urine at night, leading to waking up numerous times to visit the toilet.
5. Increased Sensitivity to Urine in the Bladder
The enlargement of the prostate can also affect the nervous system that controls the bladder, leading to hypersensitivity. This can cause the bladder to send signals to the brain to urinate even when it is not full, thereby leading to the frequent need to go to the bathroom.
6. Urinary Urgency and Weak Stream
In addition to more frequent urination, prostate enlargement also often causes urinary urgency—the sudden, urgent need to urinate. Since the urethra is obstructed, urine flow also becomes weaker, taking longer to drain the bladder. Combined, urgency and the diminished stream can add to the sensation of needing to urinate more frequently.
Summary:
Prostate enlargement leads to frequent urination primarily due to compression of the urethra by the enlarged prostate, which obstructs the flow of urine, resulting in incomplete emptying of the bladder and increased bladder irritation. This increases the sensitivity of the bladder and makes it contract more often, particularly at night. Additionally, the increased pressure from the prostate on the bladder reduces its urine-holding capacity, contributing to the feeling of needing to urinate more frequently.
The link between prostate growth (benign prostatic hyperplasia or BPH) and reduced urine flow depends on how the prostate gland cooperates with the urethra, the passageway that allows urine to go from the bladder to the exterior of the body.
This is the way in which the growth affects urine flow:
1. Prostate’s Location and Role:
The prostate is a small gland that lies just beneath the bladder and encircles the urethra. Its function is to produce fluid to nourish and transport sperm.
As a man ages, the prostate will often experience a process called benign prostatic hyperplasia (BPH), in which the gland enlarges. The enlargement is typically not cancerous but can still cause a variety of urinary symptoms.
2. Compression of the Urethra:
When the prostate gland gets larger, it narrows or shuts off the flow of the urethra by compressing the urethra that goes centrally through the enlarged prostate gland. This narrowing can shut off the flow of urethra partially or completely.
The narrowed outlet reduces the outlet pressure for urination, with less force than usual required for urinating due to increased compression.
3. Bladder Outlet Obstruction
As the prostate becomes enlarged, it can cause a bladder outlet obstruction, and that means the bladder has to strain more to push the urine through the constricted urethra. Straining may weaken or irregularize the urine stream.
The bladder may squeeze tighter to push the urine out, but because of the obstruction, it will do so weakly or slowly.
4. Straining and Incomplete Emptying
The pressure from the enlarged prostate can also cause it to be difficult to begin urinating (hesitancy) or create the feeling of not emptying the bladder after urination. This can lead to a sense of incomplete voiding.
Men with BPH can, therefore, develop straining to urinate, contributing to weak or interrupted urine flow.
5. Increased Likelihood of Urinary Retention:
In worst-case scenarios, the poor urine flow of BPH can result in urinary retention, in which the bladder cannot fully empty and urine gets backed up. This can predispose to urinary tract infections (UTIs) and bladder stones.
Conclusion:
Weak flow of the urine from the enlarged prostate arises largely from urethra compression by the prostrate mass. Such compression provides urinary tract blockage leading to slowed and feeble urinary discharge, initiation failure while passing water, and awareness of inadequate voiding of urine from the bladder. It should be taken care of through checking up on the help of a health provider or other therapy depending on medical consideration.