Pancreaticopleural fistula: a rare cause of empyema

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Dear Sir, A 40-year-old woman presented with 1-week history of fever, cough, exertional dyspnoea and pleuritic chest pain on a background of recurrent alcoholic pancreatitis. Examination revealed stony dullness with absent breath sounds of the right hemithorax suggesting massive right pleural effusion, which was confirmed on chest radiography. Initial diagnostic thoracentesis yielded turbid haemoserous fluid: pH 7.4, total protein 44 g/L (serum protein: 81 g/L), lactate dehydrogenase (LDH) 862 U/L (serum LDH: 382 U/L) and fluid amylase 12,403 U/L. Fluid cultures were negative for bacteria and mycobacteria. Thoracoscopy performed 2 days later showed turbid haemoserous fluid with pleural inflammation and fibrinous coating of the right lung. Pleuro-abdominal fistula was suspected at the medial aspect of diaphragmatic crus as fluid traversed from the abdomen to the pleural cavity during inspiration [Figure 1]. Magnetic resonance cholangiopancreatography (MRCP) revealed trans-spatial peripancreatic collections with continuous extension through the retroperitoneum and the transdiaphragmatic space. As the patient continued to be febrile, intravenous (IV) ceftriaxone was escalated to IV meropenem. Endoscopic retrograde cholangiopancreatography (ERCP) with pancreatogram showed ductal leak at the neck of the pancreas [Figure 2] that was bridged with a stent. After 3 weeks of antibiotics, the right lung did not expand with persistent hydro-pneumothorax that necessitated video-assisted thoracic surgery (VATS). The VATS revealed encasement of the right lung, diaphragm and mediastinum in empyema peel, and decortication was performed. Histology of empyema peel showed fibrous tissue admixed with neutrophils, lymphocytes, plasma cells and macrophages. There were no malignant cells seen on histology. Fluid and tissue cultures were negative, which was attributed to prior antibiotic therapy. The patient improved after VATS, and repeat imaging showed resolution of pleural effusion, retroperitoneal, peripancreatic and mediastinal collections. The pancreatic duct stent was removed 2 months later.Figure 1: Thoracoscopy images show (a) turbid haemoserous fluid upwelling from a diaphragmatic defect (arrowheads), with (b) inflamed parietal, visceral and mediastinal pleura.Figure 2: Endoscopic retrograde cholangiopancreatography images show (a) pancreatic duct leak (arrow), (b) transdiaphragmatic extension of the leak (arrowheads) and (c) resolution of the leak after removal of pancreatic duct stent.Pancreaticopleural fistula may follow rupture of the pancreatic duct as a sequela of pancreatitis. This classically occurs in chronic alcoholic pancreatitis, but can be seen in acute pancreatitis. Pancreaticopleural fistula may also occur following trauma, surgery or due to congenital abnormalities. Digestion by pancreatic juices dissects through retroperitoneal fascia and enters the thoracic cavity via diaphragmatic hiatus or direct transdiaphragmatic extension. Pleural effusions are left sided in two-thirds of cases, but may be right sided (20%) or bilateral (15%).[1] These pleural effusions are refractory to thoracocentesis. Elevated pleural fluid amylase >10,000 U/L is a key diagnostic clue, although causes of amylase-rich pleural effusions include lung malignancy, pulmonary tuberculosis, oesophageal rupture, leukaemia, lymphoma, liver cirrhosis and malignancies of the pancreas, rectum and gynaecological system.[2] The MRCP is the preferred imaging modality as it has higher sensitivity for fistula detection versus computed tomography.[3] Restoration of anatomical continuity is of greater importance than reducing pancreatic fluid production. Conservative management is usually unsuccessful. Pancreatic duct stenting and/or sphincterotomy via ERCP is recommended as it reduces the pancreatic–duodenal pressure gradient and creates a pathway of low resistance, thereby promoting drainage of fluid into the duodenum. Moreover, bridging the ductal disruption reduces flow through the fistula and facilitates closure.[4] Surgical intervention is reserved for patients who fail ERCP intervention, especially those with complete ductal disruption. Pancreaticopleural fistula may progress to empyema, critical sepsis and multiorgan failure despite endoscopic intervention. Early consideration for thoracic surgery is recommended if empyema develops.[5] Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

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