We report a case of a 60-year-old male patient with recurrent episodes of free gas in the peritoneal and the retroperitoneal cavities as well as pneumatosis intestinalis 3 months after bilateral lung transplant. Interestingly, despite staged laparotomy within the scope of the first episode, no cause for free gas could be found. In a second episode of symptomatically pneumatosis, a conservative treatment with metro_nidazole was performed successfully. Despite several case reports on patients with pneumatosis intestinalis after lung transplant, an effective treatment strategy has not yet been proposed.
Key words : Intraperitoneal free air, Lung transplantation
Free abdominal gas is in most cases a surgical emergency, and an operation is usually necessary to rule out organ perforation.1 Nevertheless, there are several reports on adult and pediatric patients with pneumoperitoneum and pneumatosis intestinalis without any evidence of organ perforation.
The potential causes range from benign to life-threatening. In addition to medication-induced pneumatosis, systemic diseases (eg, lupus or acquired immunodeficiency syndrome), inflammatory bowel diseases, and pulmonary diseases (eg, asthma or cystic fibrosis), as well as bone marrow transplant, abdominal, and thoracic organ transplant, can lead to pneumatosis intestinalis.1-7
In this case report, we present a patient with recurrent pneumoperitoneum and pneumatosis intestinalis after bilateral lung transplant in which we used a conservative approach involving antibiotic therapy with metronidazole.
A 60-year-old male patient underwent bilateral lung transplant at Hannover Medical School (Hannover, Germany) in August 2015 due to advanced lung fibrosis. In November 2015, the patient was seen during a follow-up examination at our outpatient transplant clinic. He reported pain in his upper right abdomen, which radiated into his right shoulder. A radiographic examination of the thorax showed free gas in the right subphrenic area (Figure 1A). A computed tomography scan of the abdomen confir_med the findings and also showed a pneumatosis intestinalis of the colon transversum (Figure 1B).
The laboratory results (among others) at pre_sentation were as follows: lactate concentration of 0.9 mmol/L (no acidosis), C-reactive protein level of 82 mg/L, and leucocyte count of 3500/_L. The patient's immunosuppressive regimen consisted of mycophenolate mofetil (1500 mg daily), tacrolimus (1 mg daily), and prednisolone (7.5 mg daily).
An emergency laparotomy was performed; intraoperatively, no signs of organ perforation, peritonitis, or intestinal ischemia were detected. A second-look operation the next day confirmed the initial findings; thus the abdominal wall was closed and the patient was weaned from the respirator. The patient remained in a surgical ward and was treated with metronidazole (1500 mg/d) and ampicillin/sulbactam (9000 mg/d) for 10 days.
The symptoms and C-reactive protein concen_tration steadily declined (no elevated leukocytes were observed during the complete stay), and the patient was discharged in good clinical condition after a total of 12 days in the hospital.
Four months later, the patient admitted himself to the emergency department in his hometown hospital with a distended abdomen and abdominal pain. Palpation of the abdomen did not show rebound or rigidity. Furthermore, laboratory tests depicted no serious signs of infection (normal leukocyte count and only slightly elevated C-reactive protein concentration), and lactate levels were not elevated. Apart from the abdominal pain, the patient was in good clinical condition.
After an initial radiography of the abdomen was performed, with visible evidence of free gas in the abdominal cavity, a computed tomography scan was performed showing free gas in the right retro_peritoneal area and a massive pneumatosis of the intestine, especially the transverse colon (Figures 2A and 2B). A subsequently performed colonoscopy showed no signs of ulcera or perforation.
After transferring the patient to Hannover Medical School for further surgical treatment, we reviewed the latest diagnostic results in the context of our initial findings and treatment strategy 4 months previously. Due to the good clinical condition of the patient, the normal laboratory tests, and a slightly distended but overall soft abdomen, we eventually decided not to perform another explorative laparotomy. At this point, the intake of mycophenolate mofetil was paused, the prednisolone dose was reduced to 5 mg daily, and the tacrolimus dose was increased to 1.5 mg daily.
In the following days, we extended the diagnostics by viral screening (including testing for Cyto_megalovirus and human immunodeficiency virus), ultrasonography of the abdomen, and stool culture (including testing for Clostridium difficile). None of the tests showed positive results, except for a known asymptomatic chronic infection with norovirus since lung transplant 6 months earlier.
Further therapy for symptoms was initiated. In addition to substitution of fluids and a single blood transfusion, we integrated metronidazole (1500 mg daily) into the therapy scheme due to the positive previous experiences during the first treatment course. The clinical condition of the patient steadily improved under this conservative therapy approach. After a control ultrasonographic scan was conducted (with no detection of free gas), the patient was discharged after 11 days.
Free abdominal gas is a surgical emergency in patients, and an operation is necessary to exclude perforation of an abdominal organ due to trauma or ulcer disease. Nevertheless, there are reported cases of free abdominal gas without proof of perforation of an abdominal organ or other sources for free gas.1,7,8
In lung transplant patients, there have been several reports on pneumatosis intestinalis and pneumoperitoneum without evidence of an organ perforation.2,4,6 As for the cause, Khalil and others have proposed different theories.1,5
Increased intraintestinal or intramediastinal pressure due to either bowel or pulmonary ob_struction can be responsible for dissection of gas into the bowel wall in the scope of a "mechanical theory."1 Although often present, our patient did not have clinical signs of emphysema or lung dysfunction, and the patient's pulmonary function tests showed adequate results. Furthermore, we did not find any signs of bowel obstruction despite extensive diagnostic imaging and colonoscopy, although the patient had claimed having a reduced stool frequency.
A second theory is "the bacterial theory" stating that gas-forming bacteria facilitated by a state of immunosuppression could be the reason for an accumulation of gas in the intestinal wall and the abdominal cavity.1,5 Because the patient was under immunosuppression with 3 agents (tacrolimus, mycophenolate mofetil, and prednisolone), such a mechanism could certainly explain our findings. Additionally, the described positive effects of metronidazole in the acute situation of our patient could be a hint supporting this theory and has been reported previously.5 Similarly, the effective use of other agents targeting potential pathogens like rotavirus, Cytomegalovirus, or Clostridium difficile have been reported.2
High doses of corticosteroids can lead to pneumatosis intestinalis in patients after lung transplant, as reported previously.1,6 Despite a large and heterogeneous amount of nonsurgical causes for pneumatosis, Morris and associates postulated that surgery can be necessary depending on patient history, physical examination, laboratory results, and radiologic diagnostics (eg, radiography or computed tomography scan).9 Based on previous suggestions and our own experience, we thus propose a potential diagnostic and therapeutic algorithm (Figure 3).
We previously investigated the frequency and outcome of abdominal interventions due to com_plications such as bowel perforation following heart and lung transplant.10 Notably, these were associated with a high mortality rate, leading to the suggestion for extended diagnostics and a low barrier for an early explorative laparotomy.10 This should be taken into account and points out the difficulty in finding an adequate balance between a more aggressive surgical approach and a conservative approach in patients with pneumatosis after transplant.
Despite free gas found by radiologic diagnostics, a surgical approach should be thoroughly evaluated, especially in patients with history of organ transplant and other special clinical situations that could result in ?benign? pneumatosis intestinalis.
Our presented case shows that pneumatosis intestinalis is often but not necessarily an indication for surgical exploration and that patient history, especially in those with organ transplants, should be taken into account before choosing a surgical approach.
For patients who receive a conservative thera_peutic course, continuous monitoring, including diagnostic imaging, should be implemented because of the frequent and severe abdominal complications that may occur after heart and lung transplant as previously reported.10
Metronidazole might be an effective approach for causes due to ?the bacterial theory,? as described by Khalil and associates.5 Nonetheless, further studies are needed to evaluate the cause of pneumatosis in transplant patients and to determine an adequate treatment strategy.
Volume : 17
Issue : 1
Pages : 124 - 127
DOI : 10.6002/ect.2016.0249
From the Department of General, Abdominal, and Transplant Surgery, Hannover
Medical School, 30625 Hannover, Germany
Acknowledgements: The authors have no relevant conflicts of interest and did not receive any funding. Author contributions are as follows: wrote first draft: OB, BK; contributed to writing of manuscript: OB, MK, FWRV, JK, BK; agreed with manuscript results and conclusions: OB, MK, FWRV, SC, JK, BK; jointly developed the structure and arguments for the paper: OB, MK, FWRV; made critical revisions and approved final version: FWRV, SC, JK, BK. All authors reviewed and approved the final manuscript.
Corresponding author: Oliver Beetz, Department of General, Abdominal, and Transplant Surgery, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
Phone: +49 511 532 2032
Figure 1. First Radiography and Computed Tomography Scans of the Chest and Abdomen
Figure 2. Second Radiography and Computed Tomography Scans of the Chest and Abdomen
Figure 3. Diagnostic and Therapeutic Algorithm in Patients With Pneumatosis Intestinalis