[Pneumoperitoneum as occasional finding in chronic dialysis patients--laparotomy or conservative non-operative approach?].

Free air of unknown origin within the abdominal cavity is a serious problem, which in the majority of cases indicates the perforation of a hollow organ. In two cases, we report on i) detection of free air subdiaphragmatically by coincidence during follow-up investigation of an interstitial pulmonary disease (chest X-ray) in a 67-year old patient with chronic renal insufficiency, and ii) diagnostic of pneumoperitoneum (3 times as primary diagnosis) in a 63-year old multimorbid female (with chronic renal insufficiency) with recurrent, but unspecific epigastric symptoms over a time period of 5 years. The following investigations such as endoscopy, contrast enema, and abdominal ultrasound did not detect a perforation as most likely cause. The first patient was discharged after clinical observation, laboratory and ultrasound follow-up for 5 days. In the second case, neither explorative laparoscopy during the second clinical observation period nor laparotomy for required cholecystectomy because of cholecystitis could appropriately clarify the origin. In conclusion, the detection of a pneumoperitoneum in asymptomatic patients or subjects with unspecific abdominal symptoms requires always clinical monitoring and instrumental diagnostic, consisting of endoscopy in the upper gastrointestinal tract, contrast enema of the colon and abdominal and/or thoracal computed tomography, to definitely exclude perforation. In addition, ultrasound as third column detects early low amounts of fluid and is the suitable method for short-term follow-up. The cause of pneumoperitoneum, particularly in asymptomatic patients, can not be found in every case. Under these circumstances, non-operative treatment is favored.