Michael J. Borrie, BSc, MB, ChB, FRCPC, Chair, Division of Geriatric Medicine, University of Western Ontario, London, ON.
Acute urinary retention (AUR) occurs predominantly in men and the incidence increases with age. The most common cause of urinary retention is benign prostatic hypertrophy (BPH). For men in their 40s who have no or mild obstructive symptoms (American Urologic Association Symptom Score 7 or less), the incidence of acute urinary retention is 2.6/1000 person years and 3.0/1000 person years in people with moderate to severe symptoms. In contrast, men in their 70's with mild to moderate symptoms have an incidence of AUR of 9.3/1000 person years and this rises to 34.7/1000 person years in those with moderate to severe symptoms.1 Over five years, the risk of AUR for men in their 70s is 10% and for men in their 80s it is almost 30%.1 These findings are based on a cohort of over 2,000 men 40-79, followed over four years and is one of the few longitudinal epidemiologic studies in the area.
Acute urinary retention has been defined as painful inability to void with a urine volume on catheterization of less than 800 ml.2,3 Chronic retention has been defined as the presence of the post-void residual urine volume greater than 500 mls (estimated on bladder ultrasound scan) with or without upper tract dilatation on ultrasound and/or uremia occurring in a patient who is still able to void spontaneously.