Causes of Lower Urinary Tract Symptoms

Several structural or medical conditions, either independently or in conjunction with BPH, can cause lower urinary tract symptoms. In addition, prostate growth does not always explain symptoms normally attributed to BPH. Men with large prostates do not always have symptoms, and men with small or normal-sized prostates sometimes have symptoms that are more severe than in those with enlarged glands.

Abnormalities in the Urinary Tract

Abnormalities in the urinary tract can cause BPH-like symptoms in men with or without enlarged prostate glands. Such conditions can produce obstruction, impair or weaken the detrusor muscles surrounding the bladder, or cause other damage that impacts the urinary tract. They include:

• Muscle contractions in the area where the bladder and urethra meet
• A narrowing of the urethra
• A weakened bladder
• Overactivity in prostate muscles

The male and female urinary tracts are relatively the same except for the length of the urethra.

Aging

The process of aging weakens the detrusor muscles that surround the bladder, which causes the bladder to become unstable and lose capacity. Unstable detrusor muscles may also impair bladder storage capacity, which then produce irritative or storage symptoms. Studies also indicate that as men get older they may produce more urine at night, although the total daily output of urine is similar to that in middle-aged men. It is not fully known why this occurs.

Prostatitis

Prostatitis is an inflammation of the prostate gland. It can be caused by bacterial infection, which is the easiest cause to diagnose. However, the most common form of prostatitis is nonbacterial.

Bacterial Prostatitis. A prostatitis infection can occur abruptly (acute) or be long-term (chronic). Chronic bacterial prostatitis (CBP) is often subtle and may persist for weeks or months with low-grade symptoms, including an urgent need to urinate, frequent urination, and the need to urinate at night. Pain may occur in the lower back or rectum, or it may develop after ejaculation. Because the prostate isn't swollen, doctors may mistake chronic prostatitis for BPH. A urine culture should always be taken, which, in the case of both acute and chronic bacterial prostatitis, will reveal bacteria and confirm a diagnosis. Antibiotics are required to treat CBP. Fluoroquinolones and trimethoprim-sulfamethoxazole (Bactrim, Septra) are particularly effective, but prolonged treatment may be necessary.

Nonbacterial Prostatitis. In nonbacterial prostatitis, inflammation occurs, but no bacteria are present. It is 8 times more common than bacterial prostatitis. The causes of nonbacterial prostatitis have not been determined. In one study, alfuzosin, an alpha-blocker drug that is used for BPH, provided some modest relief in patients with prostatitis and chronic pain. The routine use of drug therapy does not seem to help this condition. More research is needed.

Prostatodynia. Although it is considered a form of prostatitis, prostatodynia is a noninflammatory disorder characterized by prostate pain, but neither inflammation nor bacteria are present. The causes of prostatodynia are unknown.

Congestion of the Prostate (Prostatosis)

Congestion of the prostate, sometimes called prostatosis, is a benign condition in which the prostate seems to be swollen by excess fluid. It can cause frequent, slow, or uncomfortable urination, but it responds well to a program of frequent ejaculation and sitz baths.

Prostate Cancer

On occasion, prostate cancer can mimic BPH, since both conditions may cause obstruction of the urethra. Bladder cancer can sometimes cause urinary bleeding, frequency of urination, or a sense of urgency, also symptoms of BPH.

Click the icon to see an image of prostate cancer.

Other Conditions Affecting the Urinary Tract

Several other conditions can impair the lower urinary tract, including tumors, reactions to medications, and spinal cord injuries. Diseases that affect the nervous system, such as diabetes, multiple sclerosis, and shingles, can desensitize the nerves so that they fail to sense fullness and do not trigger the contraction of the bladder.

---

Review Date: 6/26/2006
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital