The cause behind BPH is unclear, but two factors are necessary. The first is aging and the second is the presence of dihydrotestosterone (DHT). The enlargement of the prostate, which may be extremely variable from man to man, can result in various symptoms of voiding dysfunction, either obstructive or irritative in nature.
The various symptoms associated with voiding dysfunction, including incomplete emptying, frequency, intermittency, urgency, weak stream, straining, and getting up at night. The American Urological Association (AUA) has grouped some of these complaints as a symptom index for BPH. These symptoms are not necessarily related to the size of the prostate. In fact, some men with very large prostates have only mild symptoms of voiding dysfunction. Furthermore, acute urinary obstruction with acute urinary retention may occur in men independent of the size of the enlargement. Many such men will experience a return to normal voiding patterns after one or more voiding trials with catheter removal. In some men, acute retention may be precipitated through cough and cold medications, alcohol, excessive fluids, constipation, immobilization, anesthesia or urinary tract infections.