Lesser Sac Abscess Induced Relapsing Peritonitis in a CAPD Patient

Accessible online at: www.karger.com/journals/nef Dear Sir, Peritonitis is a common complication in patients with end-stage renal disease treated by continuous ambulatory peritoneal dialysis (CAPD). It is usually caused by poor technique, exit-site infection [1, 2], tunnel infection [3, 4], perforation of hollow viscera [5], diverticulitis [6, 7], colitis [8], or cholecystitis [9], etc. It is usually easily treated by effective and adequate antibiotics in most cases. However, it becomes complicated and protracted in some cases if the uncommon abdominal abscesses cannot be found and eradicated completely [10]. However, repeated episodes of peritonitis attributed to isolated lesser sac abscess have never been reported. Herein, we report a rare case of isolated lesser sac abscess formation following repeated episodes of peritonitis in a CAPD patient. The clinical condition improved dramatically after ultrasound-guided aspiration of the lesser sac abscess. A 38-year-old woman was under CAPD therapy for 57 months. She was admitted to hospital because of epigastric pain developed and progressed to diffuse abdominal pain in the morning. It was followed by turbid dialysate effluent. The white cell count (WBC) of the effluent was 480/cm3. The peritoneal effluent culture was positive for coagulase-negative staphylococcus (CNS). Three flushings of heparinized 1.5% Dianeal dialysate were given and followed by IP antibiotics (cefazolin loading 500 mg/l, maintenance 125 mg/l and tobramycin loading 8 mg/l, maintenance 4 mg/l) immediately. The cloudy effluent became clear and WBC decreased to 1/mm3 on the 4th day. The antibiotic therapy was administered for 2 weeks. Two months later, similar symptoms and peritonitis recurred. The WBC of the effluent was 2,900/mm3. The culture of the effluent also showed CNS, which was also sensitive to cefazolin and gentamicin. The three flushings and antibiotics as above were given for 2 weeks, even though the cloudy effluent became clear and WBC of the effluent declined to 37/mm3 on the second day. However, a 3rd episode of peritonitis relapsed 1 month later. Since then, the frequency of relapsing peritonitis has increased and the interval between peritonitis episodes has been shorter even under persistent antibiotic therapy (fig. 1). The symptoms of each episode presented similarly. The pathogen of each episode of peritonitis was CNS with the same bacterial sensitivity test. On physical examination, there was no erythema or discharge from the exit site, no evidence of acute tunnel infection, no rebound pain, and no Murphy’s sign. The WBC was 6,200/mm3 with 62% neutrophils. The hematocrit was 32%. Platelet count was 283,000/mm3. Serum biochemistry showed calcium 8.9 mg/dl (reference range: 8.4– 10.6), inorganic phosphate 4.0 mg/dl (2.1– 4.7), AST 20 U/l (5–45), ALT 3 U/l (0–40), amylase 221 U/l (!190), lipase 178 U/l (!190). Computed tomography (CT) of the whole abdomen before drainage of dialysate showed no evidence of diverticulitis, spaceoccupying lesions or enlarged lymph nodes. The upper gastrointestinal (UGI) and small intestine series did not show peptic ulcer or any abnormality. The subsequent Tc99mlabeled WBC scanning for detection of intraabdominal abscess showed a negative result. Abdominal sonography after dialysate drained out revealed fluid accumulation in the lesser sac. Because there were 4 other episodes of turbid effluents happening under the antibiotic coverage after the above examinations, a 2nd sonography of the whole abdomen after dialysate drained out was arranged which also revealed fluid accumulation, sized 3!2!1.5 cm in the lesser sac (fig. 2). At this time, ultrasound-guided aspiration of the lesser sac fluid was done with the finding of 15 cm3 of turbid aspirate. The aspirated fluid culture was positive for CNS. The bacterial sensitivity test was the same as before. Eight days later, follow-up CT of the whole abdomen after the dialysate drained out showed no evidence of focal fluid accu-