[Acute urinary retention: a mechanical or functional emergency].

Acute urinary retention is one of the most frequent urologic emergencies. It occurs mostly in elderly males that suffer from prostate enlargement. Very rare in women, it is essentially caused by vaginal prolapse and neurologic disease. Patients with acute urinary retention suffer from lower abdominal pain and cannot void. Medical history is the cornerstone of diagnosis. Rarely palpable on abdominal examination, an overfilled bladder may be revealed by dullness on supra-pubic percussion. Acute urinary retention may lead to a decrease in kidney function, and on the long term to detrusor hypocontractility. The initial management is bladder drainage by urethral or suprapubic catheterization. Post obstructive diuresis and hematuria are possible complications. Subsequent evaluation is performed by the urologist on an ambulatory basis.