Operative treatment of pancreatico-bronchial fistula

Abstract

Background

Pancreatico-bronchial fistulas are a rare complication of acute or chronic pancreatitis. Both conservative and surgical management have been described previously.

Case outline

The management of a 68-year-old woman with acute pancreatitis complicated by a pancreatico-bronchial fistula was reviewed. CT scanning and magnetic resonance cholangio-pancreatography demonstrated a pancreatic pseudocyst with extension into the posterior mediastinum and right pleura. Despite conservative management as well as ERCP with pancreatic stent insertion, the fistula failed to resolve. Successful management of this difficult problem was achieved with distal pancreatectomy and intercostal drainage.

Discussion

Pancreatico-bronchial fistulas may be managed conservatively, but there should be a low threshold for surgical intervention if endoscopic measures fail.

Introduction

Pancreatic duct disruption is a serious complication of acute or chronic pancreatitis. The pseudocyst that forms can decompress into the gastrointestinal tract and thus resolve. Rupture can also occur into the abdominal cavity resulting in pancreatic ascites or into the pleura causing a pancreatico-pleural fistula. However, rupture into the bronchial tree resulting in a pancreatico-bronchial fistula is a rare complication, and both conservative and surgical management have been advocated ¹,²,³,⁴,⁵,⁶.

Case report

A 68-year-old woman was referred with abdominal pain and a pancreatic pseudocyst. Two months previously she had been admitted to another hospital with gallstone pancreatitis and underwent a laparoscopic cholecystectomy. There was no history of alcohol abuse. She had been discharged but was readmitted 4 days later with increasing pain and an elevated serum amylase. Computed tomography (CT) scan demonstrated a pancreatic pseudocyst 4 cm in size lying superior to the neck and body of the pancreas. Endoscopic ultrasound showed no retained stones within the biliary tree. On admission to this unit her liver biochemistry was normal except for an elevated alkaline phosphatase of 174 U/L. The white cell count was 11.7×10⁹ /L and amylase 616 U/L (normal <100 U/L). A new CT scan showed inflammatory changes around the pancreas with resolution of the pseudocyst.

Five days after admission she developed small bilateral pleural effusions and at 10 days she developed a productive cough (300 ml/day). The sputum was frothy and rusty-coloured and grew a methicillin-sensitive Staphlococcus aureus. Repeat CT scan on day 12 demonstrated a fluid collection in the posterior mediastinum along with small pleural effusions (Figure 1A and B). Magnetic resonance cholangio-pancreatography (MRCP) showed a leak from the pancreatic duct into a 9-cm subdiaphragmatic and posterior mediastinal fluid collection (Figure ID). On day 16 bronchoscopy showed an inflamed anterior segmental bronchus to the right lower lobe. Fluid sampled from the bronchus was analysed, and the amylase level was >85000U/L. ERCP confirmed a disrupted pancreatic duct communicating with the mediastinal pseudocyst (Figure 1C). The pancreatic duct was stented with a 7-cm 5 Ch stent. A nasojejunal tube was placed for feeding.

Figure 1. .

(A, B) CT scon demonstrating a fluid collection in the posterior mediastinum with small bilateral pleural eusions. There is also associated consolidation of the right lower lobe. (C, D) ERCP demonstrating contrast leaving the pancreatic duct to fill collections around the right lobe of the liver and the posterior mediastinum. This is also demonstrated by the MRCP in (D).

Despite conservative management her respiratory status continued to deteriorate with no decrease in the volume of bronchial secretions. Laparotomy on day 24 revealed an area of pancreatic necrosis in the body of pancreas, with complete disruption of the pancreatic duct; the tail of pancreas remained viable. The pancreatic stent was identified leaving the pancreatic duct and entering a tract that extended superiorly through the aortic hiatus into the posterior mediastinum (Figure 2). Distal pancreatectomy and splenectomy were performed, and abdominal drains were placed to the pancreatic remnant. An intercostal catheter was placed into the right chest for drainage of a symptomatic pleural effusion.

Figure 2. .

An operative photograph demonstrating the loss of the body of the pancreas due to necrosis. The pancreatic duct stent enters the cavity. A probe lies in the fistulous tract that passes into the posterior mediastinum.

Postoperatively the patient was managed in the intensive care unit and required a right mini-thoracotomy for drainage of an empyema on day 35. She developed a pancreatic fistula that was well drained by the abdominal drain tubes, and diminished with octreotide therapy. She required a tracheostomy to wean from the ventilator and she was discharged to the ward in the 10th week of her admission. Thereafter the pancreatic fistula resolved spontaneously, and she went home 14 weeks after admission.

Discussion

Pancreatico-bronchial fistula as a complication of acute or chronic pancreatitis is a rare entity, and confirmation of the diagnosis can be difficult. Estimation of the amylase concentration of pleural fluid is essential in the diagnosis of a pancreatico-pleural fistula ⁷. Sputum cannot be used to confirm the presence of amylase-rich fluid due to contamination with salivary amylase and so samples should be obtained by broncho-alveolar lavage. The findings at bronchoscopy are non-specific with an inflamed and oedematous mucosa but no obvious fistula.

CT or magnetic resonance imaging (MRI) can help in the imaging of peripancreatic, pleural and mediastinal fluid collections. In this case MRCP was required to delineate the fluid collection in the posterior mediastinum. ERCP also has a role in further defining the anatomy of the pancreatic duct. No previous attempts at endoscopic stenting of the pancreatic duct for a pancreatico-bronchial fistula have been reported.

Including this report there are 18 patients for whom details have been published regarding the management of pancreatico-bronchial fistulas ¹,²,³,⁴,⁵,⁶, many preceding the era of octreotide or endoscopic pancreatic duct stenting. Two patients had successful conservative management, 15 had successful surgical management and one patient died within 48 hours of admission (Table 1).

Table 1. Pancreatic pathology and treatment in 18 reported cases of pancreatico-bronchial fistula.

Patient no.	Pancreatic pathology	Reference no.	Conservative management	Successful surgical management
1	Acute pancreatitis			Distal pancreatectomy
2	Acute pancreatitis	2		Distal pancreatectomy
3	Acute pancreatitis	3		Distal pancreatectomy
4	Acute pancreatitis	2		Subtotal pancreatectomy and drainage empyema
5	Acute pancreatitis	3		Necrosectomy and left pulmonary lobectomy
6	Acute pancreatitis	3		Necrosectomy with colonic diversion
7	Acute pancreatitis	2		Surgical external drainage
8	Acute pancreatitis	2		Surgical external drainage
9	Acute pancreatitis	2		Surgical external and thoracic drainage
10	Acute pancreatitis	2		Surgical external and thoracic drainage
11	Acute pancreatitis	2		Removal impacted stone and external drainage
12	Acute pancreatitis	2		Internal (gastric) and external drainage
13	Acute pancreatitis	2	Tube thoracosotomy
14	Chronic pancreatitis	6		Subtotal pancreatectomy and external drainage
15	Chronic pancreatitis	2		Pancreaticojejunostomy
16	Chronic pancreatitis	4		Pancreatic resection
17	Chronic pancreatitis	5	Conservative with protease inhibitor5
18	Chronic pancreatitis	1	Supportive – died

The development of a pancreatic fistula to the bronchus, mediastinum or pleura is a recognised complication of pancreatic pseudocyst rupture. Some aspects of the management of a pancreatic pseudocyst may be applicable to the management of a pancreatico-bronchial fistula, although it is important to distinguish between those associated with acute or chronic pancreatitis ⁸. Nealon and Walser recently studied the anatomy of the main pancreatic duct in pancreatic pseudocysts ⁹, and concluded that percutaneous drainage alone was possible in patients with a normal duct that did not communicate with the pseudocyst. Furthermore, transpapillary drainage may be attempted at this time, although long-term results have not been as good ¹⁰. In our patient the pancreatic duct communicated directly with the cyst and resolution did not occur with ductal drainage. The delineation of pancreatic ductal anatomy with ERCP or MRCP should be performed in patients with pancreatico-bronchial or pleural fistulas, but most patients will require surgical intervention, especially following acute pancreatitis (Table 1).

Many reports on the management of pancreatico-pleural fistulae suggest initial conservative management with tube thoracostomy with or without octreotide ¹¹,¹². Others have reported the successful resolution of peripancreatic fluid collections and rupture of the pancreatic duct with endoscopic stenting of the pancreatic duct ¹⁰. Fekete and associates ³ described three patients with pancreatico-bronchial fistula in the setting of severe acute necrotising pancreatitis with respiratory compromise and suggested that the fistula was often overlooked in this setting. Pancreatico-bronchial fistula is an extension of the same process that has already led to pancreatic duct rupture, peripancreatic fluid collections and pancreatico-pleural fistula. However, patients with pancreatitis and a chronic leak of pancreatic fluid into the bronchial tree with resultant respiratory compromise will not have the same reserves to tolerate a prolonged period of conservative management.

Although rare, pancreatico-bronchial fistulas should be considered in any patient with pancreatitis who develops productive watery sputum. Management requires pancreatic ductal imaging and a low threshold for operation if chemical respiratory inflammation continues.