Incomplete emptying of the bladder may be the result of constipation, nerve problems, weak bladder muscles, urinary tract stones, blockage or narrowing of the urethra and some types of cancer, explains the National Kidney and Urologic Diseases Information Clearinghouse. The problem can also be caused by certain medications.
The inability to completely empty the bladder is also referred to as urinary retention, notes the NKUDIC. The problem can be either acute or chronic. Acute urinary retention is the inability to urinate even where the bladder is full. The onset of symptoms is typically sudden. The condition causes extreme levels of pain and discomfort and requires immediate medical attention. In contrast, chronic urinary retention, which leads to incomplete emptying of the bladder, causes little or no discomfort. For this reason, sufferers may remain unaware of the problem for years.
One cause of urinary retention is the partial or complete blockage of the urethra, explains the NKUDIC. Such blockage may be the result of urinary tract stones, tumors, prostate enlargement and urethral strictures. Cystocele, a condition where the bladder bulges into the vagina, and rectocele, the bulging of the rectum into the vagina, also lead to urinary retention. Nerve problems resulting from heavy metal poisoning, strokes, diabetes, multiple sclerosis, pelvic injury, vaginal childbirth and other causes may also cause urinary incontinence.