Necrotising fasciitis secondary to intra-abdominal sepsis

Abstract

Dear Editor: Necrotising fasciitis (NF) is a soft tissue infection where a microorganism or microorganisms spread along superficial and deep fascial planes. NF as a disease entity was first described by Hippocrates circa 500 BC, but it was not until 1952 that the term necrotising fasciitis was coined. The spread is facilitated by bacterial exotoxins such as streptococcal pyrogenic exotoxins (SPEs) A, B, C which are directly toxic. SPEs cause thrombosis of perforator vessels, resulting in tissue necrosis. SPEs also lead to the production of cytokines causing clinical signs, such as sepsis. Surface protein expression increases streptococcal adherence to tissues and also protects bacteria against phagocytosis by neutrophils. Herein, we report a case of NF caused by a perforated rectal carcinoma, and we review the literature to reveal other intra-abdominal causes of necrotising fasciitis. A 53-year-old gentleman was admitted in septic shock with a 7-day history of abdominal pain and limping. The patient had a background history of recent onset diarrhoea and weight loss. On examination, his abdomen was distended, with localised peritonitis in the left iliac fossa. There was a large area of erythema and palpable crepitus on the posterior aspect of his left thigh extending from the gluteal fold to the mid thigh. Proctoscopy revealed frank pus in the rectum with no signs of a perineal source of sepsis. Blood tests showed a white blood cell count of 12.2, and C-reactive protein was 269. He was initially fluid-resuscitated and treated with cefuroxime and metronidazole. Computed tomography (CT) scan of the abdomen and pelvis revealed extensive free air in the left upper thigh. Air fluid levels were also visualised. Within the pelvis, there was circumferential thickening of the sigmoid and rectal wall and extensive pre-rectal inflammatory change and enlarged retrocrural and para-aortic lymph nodes. A provisional diagnosis of necrotising fasciitis secondary to perforated diverticulitis or a perforated neoplasm was made, and the patient proceeded on an emergent basis to a laparoscopy, lavage, and defunctioning transverse colostomy. Ensuing exploration of the left thigh and pelvic floor revealed the offensive purulent material and findings were consistent with necrotising fasciitis. Extensive debridement of all involved tissues, including skin, fascia, and muscles including semi-membranosus, semi-tendinosus, and gracilis was carried out. A washout of wounds and redressing was carried out every 48 h. A split-thickness skin graft was used to close the wounds once the patient had improved clinically 3 weeks later. Microbiology confirmed the presence of Escherichia coli and mixed anaerobes from wound swabs. Histology later confirmed that the debrided tissue was consistent with necrotising fasciitis. Flexible sigmoidoscopy was performed, and a tumour was visualised at 5 cm. Biopsies taken showed evidence of rectal adenocarcinoma. The tumour was staged radiologically as T4N2Mx. Neoadjuvant chemoradiotherapy was used following complete wound healing. The chemotherapy regime included five cycles of 5-fluorouracil (5-FU). Twenty-five fractions of radiotherapy were used. The patient subsequently underwent an abdominoperineal resection. Histology confirmed D. P. O’Leary (*) : E. Myers :M. McCourt Department of Surgery, Cork University Hospital, Wilton, Cork, Ireland e-mail: Olearypeter83@hotmail.com