Bladder outlet obstruction: etiology and evaluation.

Numerous gender-specific etiologies are responsible for bladder outlet obstruction (BOO). BOO may be induced by specific functional and anatomic causes. The resulting obstruction frequently produces lower urinary tract symptoms (LUTS). Categorizing and understanding these entities is crucial when proceeding with a LUTS evaluation as specific diagnostic modalities may then be used to fully delineate the degree of BOO and any secondary issues. Although urodynamic evaluation and pressure flow evaluation is the gold standard diagnostic tool, other modalities may also be used, including post void residual analysis, urinary flow rates, cystoscopy, and selected radiologic ones. Patient self-appraisal of symptoms using various inventories such as the American Urologic Association Symptom Index or the International Prostate Symptom Score is relevant to the initial assessment and subsequent longitudinal follow up. Analysis of secondary symptoms of obstruction in women is often performed using a subjective symptom appraisal and is determined urodynamically, assessing the pressure-flow relation during voiding. The complete assessment of LUTS arising from BOO often includes several of these modalities to fully define the obstructive impact on the individual's urinary function and quality of life.