Pleuroperitoneal Diaphragmatic Communication: A Rare Complication in Patients on Peritoneal Dialysis after Cardiac Surgery

Introduction: Pleuroperitoneal diaphragmatic communication (PPDC) is an extremely rare but serious complication of peritoneal dialysis (PD). Elevated intra-abdominal pressure creates a fistula between the pleural and peritoneal spaces, allowing peritoneal fluid migration and causing effusions or hydrothorax. While approximately 25% of patients are asymptomatic, presentations include dyspnea or, in extreme cases, lung collapse. To our knowledge, this is the first case of PPDC described in the literature post-cardiac surgery. Case Description: A 57-year-old female with end-stage renal disease due to focal segmental glomerulosclerosis, recently started on PD and undergoing transplant evaluation, presented with NSTEMI and multivessel coronary artery disease. Post-coronary artery bypass grafting (CABG), she received continuous renal replacement therapy. After her bilateral surgical chest tubes were removed, she resumed PD when off vasopressors three days later. The next day, a routine chest X-ray revealed new bibasilar opacities, and chest CT showed large bilateral pleural effusions. Given her significant negative fluid balance, these large effusions in the absence of hypoxemia were concerning for a pleuroperitoneal leak due to recent chest tubes. Pleural fluid glucose was elevated compared to serum levels. A right chest tube was placed, and she transitioned to hemodialysis with improvement. Discussion: PPDC, although exceedingly rare, should be considered in PD patients with pleural effusions, particularly if volume negative and postsurgical. PPDC usually arises from increased intra-abdominal pressure due to large-volume PD solution instillation, coughing, straining, or trauma, allowing peritoneal fluid to traverse the diaphragm. In postsurgical patients, recent chest tubes or diaphragmatic instrumentation may be the cause. Elevated pleural fluid glucose indicates peritoneal dialysate presence; MRI or scintigraphy can confirm a fistula. Management includes a PD holiday, pleural cavity tetracycline instillation, surgical patch grafting of the diaphragm, or talc pleurodesis.CXR with BL chest tubes (left), CXR after chest tube removal with new effusion (middle), CT chest with BL effusions