[Acute renal failure related to urinary retention following haemorrhoidectomy performed under general anaesthesia and bilateral pudendal nerve block: a case report].

Anorectal surgery is associated with significant postoperative pain. Pudendal nerve blocks, formerly performed by surgeons, provides effective postoperative analgesia and allow a quicker recovery, which is quite important in the current concept of fast-track postoperative care. However, even for benign surgery with a safe anaesthetic technique, serious adverse events may occur. We report a case of acute renal failure related to urinary retention. Hidden by a prior history of urination difficulties, recognition of symptoms, following haemorrhoidectomy performed with bilateral pudendal block, was late. After complete recovery, electrophysiologic investigations found hypotonic, hypocontractile bladder.Therefore, before performing haemorrhoidectomy with regional anaesthesia, prior history of urination difficulties should be searched. The risk of urinary retention due to surgery and anaesthesia may be increased, as observed in this original case report.