Can an Enlarged Prostate Damage the Bladder or Kidneys?
Benign prostate enlargement can obstruct the flow of urine from the bladder. In many men, this causes bothersome urinary symptoms without damaging the urinary system. However, persistent or severe obstruction can sometimes lead to incomplete bladder emptying, urinary retention, infections, bladder stones and, less commonly, kidney problems.
The presence and severity of symptoms do not always show how much obstruction is present. An individual assessment may therefore include urine-flow measurement, assessment of the urine remaining in the bladder and, when indicated, blood tests or imaging.
Further information about symptoms and assessment is available on the enlarged prostate page.
How Does an Enlarged Prostate Affect Urination?
The prostate surrounds the first part of the urethra, which carries urine from the bladder through the penis. As the prostate enlarges, it may compress or distort this channel and increase the resistance against which the bladder must empty.
The bladder initially compensates by contracting more strongly. This may allow urine to continue flowing despite the obstruction. Over time, however, some patients develop a weaker urinary stream, hesitancy, straining, interrupted flow or a sensation that the bladder has not emptied completely.
Prostate size alone does not determine the severity of obstruction. A moderately enlarged prostate in a particular position may cause significant difficulty, while some men with a larger prostate continue to empty their bladder reasonably well.
Can an Enlarged Prostate Damage the Bladder?
Persistent obstruction can cause structural and functional changes in the bladder. The bladder muscle may become thicker because it repeatedly works against increased resistance. The inner bladder wall may develop an irregular appearance known as trabeculation, and small outpouchings called diverticula can occasionally form. In some patients, the bladder eventually becomes less effective at contracting. This may leave an increasing amount of urine behind after urination. A persistently elevated post-void residual can contribute to urinary frequency, urgency, recurrent infections, bladder stones or urinary retention.
Not every man with urinary symptoms develops these complications. Many patients remain stable for years, particularly when their symptoms are mild and bladder emptying remains satisfactory.
What Is Urinary Retention?
Urinary retention means that the bladder cannot empty adequately.
Acute urinary retention occurs when a person suddenly becomes unable to pass urine despite having a full and often painful bladder. This requires urgent medical attention and usually immediate drainage with a urinary catheter.
Chronic urinary retention develops more gradually. The bladder may retain a significant volume of urine without causing severe pain. Some patients notice a weak flow, frequent small voids, abdominal swelling, leakage from an overfilled bladder or worsening symptoms at night. Others may have relatively limited symptoms despite retaining a substantial volume.
Chronic retention requires assessment because prolonged back pressure can occasionally affect the upper urinary tract and kidneys. NICE recommends specialist assessment when lower urinary tract symptoms are complicated by retention, recurrent infection or suspected renal impairment.
Can an Enlarged Prostate Affect the Kidneys?
Kidney damage caused by benign prostate obstruction is uncommon, but it can occur when severe or prolonged urinary retention creates pressure within the bladder and upper urinary tract. Urine may back up towards one or both kidneys, causing dilatation known as hydronephrosis. If this continues, kidney function may deteriorate. Chronic urinary retention associated with impaired renal function or hydronephrosis normally requires drainage and further treatment of the obstruction.
Kidney impairment in a patient with urinary symptoms is not automatically caused by the prostate. Diabetes, high blood pressure, medication and other kidney or urinary conditions may also be responsible. The complete clinical picture must therefore be assessed.
Do Severe Symptoms Always Mean There Is Damage?
No. The intensity of urinary symptoms does not always correspond to the degree of obstruction, the amount of urine remaining in the bladder or kidney function.
Some men are very troubled by frequency and urgency but empty their bladder effectively. Others adapt gradually to a weak stream and incomplete emptying and may not appreciate how much urine remains after urination. This is why treatment decisions should not be based on symptoms or prostate size alone.
How Is Bladder Emptying Assessed?
A urological assessment may include:
discussion of urinary symptoms and their effect on daily life;
examination of the abdomen and prostate;
urine testing;
PSA testing, when appropriate;
uroflowmetry to measure the strength and pattern of urinary flow;
ultrasound measurement of the post-void residual;
assessment of prostate size and anatomy;
kidney-function blood tests when renal impairment is suspected;
kidney and bladder imaging when clinically indicated.
Cystoscopy or urodynamic testing may be recommended in selected cases, but these investigations are not required for every patient with uncomplicated urinary symptoms.
Which Findings May Make Treatment More Urgent?
Treatment may become more important when benign prostate obstruction is associated with:
recurrent or persistent urinary retention;
repeated urinary infections;
bladder stones;
recurrent visible blood in the urine attributed to prostate enlargement;
significant incomplete bladder emptying;
overflow urinary leakage;
hydronephrosis;
deterioration in kidney function;
symptoms that remain troublesome despite appropriate medication.
The European Association of Urology identifies recurrent retention, infections, bladder stones, upper urinary tract dilatation and inadequate relief with conservative or medical treatment as circumstances in which surgery may be required.
Does Every Enlarged Prostate Require Surgery?
No. An enlarged prostate does not automatically require treatment, and many men with mild uncomplicated symptoms can be managed with observation, lifestyle measures or medication. Surgery may be considered when symptoms remain bothersome despite treatment, medication causes unacceptable side effects or complications of obstruction develop.
Available procedures include TURP, laser surgery, Aquablation and other prostate-reduction techniques. The most appropriate treatment depends on prostate size and anatomy, bladder function, general health, medication, priorities regarding sexual function and the surgeon’s assessment.
More information is available on the prostate reduction surgery and Aquablation surgery pages.
When Should You Seek Urgent Help?
Seek urgent medical assistance if you are unable to pass urine, particularly when the lower abdomen feels painful or swollen. You should also seek prompt assessment if urinary symptoms are associated with fever, visible blood in the urine, severe pain, recurrent infections or a significant deterioration in your general health. The NHS advises urgent assessment when a person cannot pass urine at all.
The Bottom Line
Most men with benign prostate enlargement do not develop permanent bladder or kidney damage. Nevertheless, prolonged or severe obstruction can lead to incomplete emptying, urinary retention, infection, bladder stones and, less commonly, hydronephrosis or impaired kidney function.
Symptoms alone cannot always determine whether the bladder is emptying safely. Uroflowmetry, post-void residual measurement and selected blood tests or imaging can help establish whether observation, medication or surgical treatment is appropriate.
Arrange a Consultation
If you have a weak urinary stream, difficulty emptying your bladder, recurrent urinary infections or concerns about an enlarged prostate, Dr Carlo Bravi offers private urology consultations in London and Northampton.
An individual assessment can review your symptoms, bladder emptying, prostate investigations and available treatment options.
Arrange a consultation or check the earliest available appointment.
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