Pathophysiology, epidemiology, and natural history of benign prostatic hyperplasia.

The pathophysiology, epidemiology, and natural history of benign prostatic hyperplasia (BPH) are incompletely understood; however, the development of reliable instruments to measure symptom severity, prostatic enlargement, and bladder outlet obstruction has allowed major advances in their elucidation. The development of lower urinary tract symptoms (LUTS) in the aging male is influenced to some degree by the severity of bladder outlet obstruction and prostatic enlargement. Although the development of LUTS, bladder outlet obstruction, and BPH are age-dependent, they are not necessarily causally related; there are many other factors involved in the pathophysiology of LUTS. The clinically important parameters of disease progression in men with moderate to severe LUTS and low peak flow rates are symptom progression and the development of acute urinary retention (AUR). The risk of AUR is related to both baseline serum prostate-specific antigen level and prostate volume. In men with moderate prostate enlargement, the risk of AUR appears to be high enough to justify intervention with a 5alpha-reductase inhibitor in order to reduce this risk.