Omental necrosis masquerading as urinary retention following laparoscopic Roux en Y gastric bypass for super obesity
A 55-year-old man presented for an elective laparoscopic Roux en Y gastric bypass for super obesity. His previous medical history included insulin dependent diabetes, hypertension, obstructive sleep apnoea, intervertebral disc disease and ischaemic heart disease. His admission body mass index (BMI) was 50 and this represented an improvement from an original BMI of >65 at clinic. Following an uncomplicated intraoperative procedure he developed severe lower abdominal pain on the first postoperative day.\nOver a couple hours the pain became centralized and was relieved by lying prone. He became gradually distended and complained of being unable to pass urine but had no other abdominal symptoms. On examination he had a pulse of 120 beats/min and a blood pressure of 145/80 mmHg. He had a respiratory rate of 25 breaths/min and was saturating at 94% on 2 L O2 (via nasal cannulae). Clinical examination of his abdomen revealed that he was not obstructed and had no signs of peritonitis. However, a large supra-pubic mass was palpable. He had a large residual volume of urine (>800 mL) that was not amenable to urethral catheterization necessitating the involvement of a urological team to insert a supra-pubic catheter.\nHe continued to experience worsening abdominal pain throughout the second postoperative day. His abdomen became more distended causing him to become short of breath thus increasing his oxygen support (i.e. >4 L O2 via a face mask). An arterial blood gas demonstrated a developing lactic acidosis (i.e. >3.0) and a high leukocytosis (>18,000/mm3). Computed tomography (CT) chest and abdomen confirmed consolidation and a pleural effusion but no obvious abdominal pathology. This excluded the original clinical suspicion of an anastomotic leak (Figure ). Ultrasound (USS) was not performed.\nDue to inconclusive imaging and the lack of a definitive diagnosis he was taken back to theatre for a mandatory re-laparoscopy. This revealed a non-specific fibrinous coating over the small bowel. On deeper inspection the anastomosis appeared intact and healthy (no anastomotic air leak was demonstrated). However, a large segment of necrotic omentum was found and subsequently divided and removed. No other abdominal pathology was identified. Pathological examination revealed vascular congestion and omental necrosis. The patient made a good recovery and was discharged home a couple weeks later.