Gastro pulmonary fistula complicating gastric bypass

Clinical History

A morbidly obese female patient had undergone gastric bypass which was complicated by a postoperative leak and abdominal abscess. Chronic abdominal pain and recurrent pneumonia afflicted the patient. An upper gastrointestinal contrast study demonstrated a gastropulmonary fistula - a rare complication.

Imaging Findings

A 38-year-old morbidly obese female patient underwent gastric bypass in December 2003. This operation was complicated by a postoperative leak resulting in a sub-diaphragmatic abscess. She was non-operatively managed for several years. The patient suffered from chronic abdominal pain and recurrent pneumonia. A second laparotomy was performed in August 2008 for abscess washout. However, her symptoms returned. She was diagnosed with a recurrent abscess on a CT examination. She presented to our Bariatric Clinic. A contrast upper gastrointestinal (UGI) study was ordered. During the procedure iodinated contrast was seen to enter the gastric pouch and spill into the excluded gastric remnant, consistent with a gastro-gastric fistula (Fig. 1). Another large leak was also identified from the gastric pouch, this communicated with the known subphrenic abscess cavity (Fig. 1). As the fluoroscopic images were being obtained with patient swallowing oral contrast in the supine position, she developed intense cough. Aspiration was suspected and the study was paused (Fig. 2). On reviewing the images, it became evident that contrast was not aspirated, but instead had tracked upward from the subphrenic abscess, across the diaphragm into the airway suggesting a gastropulmonary fistula. The study was resumed in the semi-upright position to confirm this. As contrast passed from the gastric pouch into the bronchioles, an air contrast level developed (Fig. 3). Given these findings we questioned the patient in greater detail regarding her symptoms. She reported coughing up food particles ingested the previous day which she had mistaken for reflux.

Discussion

Gastropulmonary fistula (GPF) complicating gastric bypass surgery is very rare. GPF however has been described before. Review of literature identifies gastro-oesophageal surgery, subphrenic abscess, trauma and gastric ulcer as possible aetiologies. It has also been reported in patients who have undergone oesophagectomy with oesophagogastric anastomosis and in patients who have undergone Nissen fundoplication (trans-thoracic as well as trans-abdominal approach) [1, 2]. Surgical procedures such as laparoscopic adrenalectomy and splenectomy with inadvertent injury to the stomach have also been complicated by the occurrence of GPF [3].
The postulated pathophysiology of GPF includes technical issues resulting in poor viability of gastric wall secondary to excessive dissection that leads to ischemia along the staple lines versus inadvertent injury to the gastric serosa at the time of surgery [3, 4]. Ulcer disease in the gastric pouch is another likely cause [5]. With development of a perforation and leak, gastric secretions move to the subphrenic region and cause an intra-abdominal abscess. When such a subphrenic abscess is chronic, it results in spread of infection across the left hemidiaphragm, through lymphatics or by direct erosion, resulting in a pleural abscess. Once the pleural abscess erodes into a bronchiole, a GPF develops [5].
Common presentations of patients with GPF include coughing of gastric contents after a meal, haemoptysis and recurrent chest infections [4, 5]. As diagnosis is usually delayed, patients typically present in poor general condition secondary to malnutrition and chronic pulmonary infection [4].
UGI contrast study, UGI endoscopy, bronchoscopy and CT are the recommended diagnostic modalities. A contrast study of the UGI tract is the most successful means of diagnosing a GPF. Care must be taken not to misinterpret the findings for aspiration [2]. Images need to be acquired quickly as the contrast medium starts to fill the fistula, as delay may lead to excess contrast medium in the subdiaphragmatic abscess concealing the fistula. Use of a semi-upright position can help to control the amount of contrast medium entering the fistula.
Bronchoscopy will only show a fistulous tract if the tract opens into a large, proximal bronchus. Other methods that have been used include Methylene Blue staining and measurement of bronchial secretion pH [5, 6].
Surgical treatment includes division of the fistula with debridement of the gastric perforation, diaphragmatic repair with or without resection of the affected segments of the lung [5]. Limited resection versus redo of the gastric pouch may be required. Use of tissue flap or omentum to provide viable tissue between the repairs may be required.
In the area gastric bypass surgery, GPF is a rare but serious complication. What has been reported as a complication of oesophagectomy with gastric conduit reconstruction is now being reported in patients who develop anastomotic leak following Gastric Roux en Y bypass (GRYBP). Diagnosis can be difficult and clinically confusing. Awareness of this uncommon complication will help diagnose this rare condition in patients presenting with recurrent pneumonia or refractory haemoptysis following GRYBP.

Differential Diagnosis List

Final Diagnosis

Gastropulmonary fistula complicating gastric bypass.

URL:	https://www.eurorad.org/case/8254
DOI:	10.1594/EURORAD/CASE.8254
ISSN:	1563-4086