Relapsing Pleural Effusion in a Patient on Automated Peritoneal Dialysis

TO THE EDITOR

Pleural effusion is a known complication of continuous ambulatory peritoneal dialysis (CAPD). We present the case of a patient who had recurrent right pleural effusion while on automated peritoneal dialysis (APD) that resolved when intermittent hemodialysis (IHD) was instituted.

CASE REPORT

A 54-year-old male presented with new-onset right pleural effusion. He had a history of metastatic squamous cell carcinoma of the right tonsil for which he underwent chemoradiation therapy, and he had been recently diagnosed with end-stage renal disease requiring dialysis because of polycystic kidney disease. He was originally started on IHD but was changed to CAPD at his request. After a few months of CAPD, the patient was switched to APD to minimize his dialysis time and improve his quality of life. Two weeks after he started APD, the patient complained of shortness of breath. Chest imaging confirmed moderate right pleural effusion. Diagnostic and therapeutic thoracentesis was performed. Pleural fluid analysis demonstrated transudative pleural effusion with a pleural fluid glucose level of 256 mg/dL. The gradient between the pleural fluid glucose and the serum glucose was >100 mg/dL without cytologic evidence of malignant cells. Pleural effusion attributable to intraabdominal dialysate leakage into the pleural space through a transdiaphragmatic defect was highly suspect. Consequently, APD was temporarily converted to IHD with resolution of symptoms. After 2 weeks of IHD, APD was reinstituted, and the right pleural effusion recurred. Repeat thoracentesis demonstrated a pleural fluid profile similar to that of the previous occurrence. Because of his comorbidities, the patient declined other invasive treatment options. He decided to resume IHD, and the right pleural effusion completely resolved.

DISCUSSION

This case demonstrates the occurrence of pleural effusion with APD that did not occur when the patient was on CAPD. The incidence of pleural effusion in association with CAPD ranges from 2%-10%, particularly right pleural effusion with an incidence of up to 88%.1 The incidence of left pleural effusion attributable to diaphragmatic defect is lower because the pericardium covers the defect and prevents peritoneal fluid leakage into the left pleural space. The pathophysiology of developing pleural effusion in patients on APD could be explained by the presence of a transdiaphragmatic defect or the higher pleuroperitoneal pressure gradient caused by the gravitational effect of lying supine at night with the intraabdominal cavity containing dialysate during APD instead of being in the recumbent position of CAPD. Also, pumping the dialysate with APD increases the pressure gradient between the peritoneal and pleural space that can worsen the leakage through a transdiaphragmatic defect. The diagnosis of right pleural effusion from leakage of peritoneal dialysate is highly suspicious when the gradient between the pleural fluid glucose and the serum glucose is >100 mg/dL.2 The lower glucose gradient does not preclude intraperitoneal dialysate leakage because the pleural mesothelial cells could metabolize the pleural fluid glucose. In such circumstances, imaging studies (eg, peritoneal scintigraphy) are required to demonstrate the transdiaphragmatic defect. First-line treatments are temporary cessation of peritoneal dialysis or low-volume exchange.3 If conservative management is unsuccessful, minimal invasive procedures such as video-assisted thoracoscopic surgery (VATS) with chemical pleurodesis or direct suturing of the transdiaphragmatic defect with or without a Teflon patch might allow the patient to continue on APD.4 Open thoracotomy for pleurectomy or mechanical pleural abrasion is rarely performed because the advantage of VATS compared to traditional thoracotomy has been well documented.

We emphasize the importance of looking beyond the common etiologies of transudative pleural effusion, such as decompensated congestive heart failure, nephrotic syndrome, hepatic hydrothorax, or hypoalbuminemia, and considering the type of peritoneal dialysis being performed. A systematic review by Rabindranath et al reported no difference in mortality, hospitalization, and incidence of peritonitis between APD and CAPD, but APD is associated with improved quality of life.5 The question of whether the intraabdominal pressure in APD is higher than CAPD and complicates right pleural effusion in patients with transdiaphragmatic defect requires further investigation.