Case report of postoperative urinary retention resolution following neostigmine administration in a patient with multiple risk factors for POUR

Postoperative urinary retention (POUR) is a common complication of surgery and anesthesia, with an incidence of 4–5% in elective procedures. POUR is traditionally managed with bladder catheterization, which carries risks of infection, urethral trauma, and prolonged hospitalization. Pharmacologic alternatives such as alpha-adrenergic antagonists or cholinergic agonists have been trialed, but with variable efficacy. Neostigmine, an acetylcholinesterase inhibitor, enhances parasympathetic activity to promote detrusor contraction and may represent a noninvasive treatment option, although its use in POUR is rarely reported. We report the case of a 73-year-old male with a history of benign prostatic hyperplasia (BPH), bladder cancer status-post transurethral resection of bladder tumor (TURBT), and interstitial pulmonary fibrosis, who presented for magnetic resonance image (MRI)-guided transperineal prostate biopsy. The procedure was performed under general anesthesia and tolerated without complication. Postoperatively, the patient developed acute urinary retention with a bladder volume of 565 mL that persisted for over 5 h despite ambulation, caffeine, and tamsulosin administration. Wishing to avoid catheterization, the patient elected to trial neostigmine after a risk-benefit-alternatives discussion. A 0.5 mg intravenous injection of neostigmine was administered. Complete voiding occurred within 20 min after the injection without adverse hemodynamic effects, and the patient was discharged home promptly. This case illustrates a temporal association between neostigmine administration and resolution of POUR; a single case cannot establish efficacy or causation. Postoperative urinary retention developed in a patient with multiple risk factors for POUR after MRI-guided transperineal prostate biopsy and persisted despite conservative management. A single 0.5 mg intravenous dose of neostigmine resulted in complete bladder emptying within 20 min, avoiding bladder catheterization without adverse effects. This case describes neostigmine administration in a carefully monitored patient with established postoperative urinary retention and warrants further prospective investigation.