A Novel Diagnostic Approach for Suspected Icodextrin Pleural Effusion in a Peritoneal Dialysis Patient

Symptomatic pleural effusion secondary to pleuroperitoneal communication in patients undergoing peritoneal dialysis (PD) occurs in approximately 2% of patients undergoing continuous ambulatory PD. The classic presentation is that of a low-protein, high-glucose pleural aspirate consistent with the high dextrose concentrations present in standard PD fluids, hence the name sweet hydrothorax. Nevertheless, the increasing use of icodextrin calls for an innovative bedside diagnostic approach because icodextrin does not contain high concentrations of dextrose after all. We describe a patient with newly symptomatic right pleural effusion 2 months after starting continuous ambulatory PD with 2 exchanges every 12 hours. Prompt relief was achieved with therapeutic thoracentesis, but the pleural aspirate had less than 2 g/dL of protein (to convert to g/L, multiply by 10) and a glucose level of 108 mg/dL (to convert to mmol/L, multiply by 0.0555), lower than the blood glucose level of 139 mg/dL in the emergency department earlier the same night. The patient was allergic to iodinated contrast. We, therefore, used an innovative approach with biochemical fingerprint analysis of simultaneous pleural and peritoneal fluids for electrolytes, urea, creatinine, and measured osmolality. With the increasing use of icodextrin in contemporary PD worldwide, this innovative tactic is cheap, is easily available, and does not require sophisticated, expensive, and often unavailable options, such as isotope studies, dye studies, and iodinated contrast-enhanced computed tomography. To our knowledge, this is the first time that biochemical fingerprint analysis of simultaneous pleural and peritoneal fluids has been reported in the literature.