INTRODUCTION: Chylothorax is characterized by the collection of high lipid content fluid within the pleural space, usually due to thoracic duct disruption. Trauma is the cause in 30–50% of cases. Non-traumatic chylothorax is most often the result of lymphadenopathy. Similarly, disruption of chyle flow within the peritoneal cavity can result in chylous ascites. Chylothorax can occur as a result of chylous ascites as the negative intrapleural pressure draws chyle through diaphragmatic defects into the pleural space. In this case, we present a rare cause of chylous ascites, the nephrotic syndrome, resulting in chylothorax.
CASE PRESENTATION: A 53 y/o white female presented to the emergency department with a complaint of dyspnea. She had a history of CLL and matched unrelated donor stem cell transplant. Three weeks before presentating, she had a bronchoscopy with brochioalveolar lavage (BAL) to evaluate progressive dyspnea and bibasilar infiltrates. Viral culture from the BAL was positive for adenovirus. In response to this culture, cidofovir was initiated 8 days prior to presentation. At presentation, respirations were 20 per minute with room air SpO2 88%. She was without lymphadenopathy, hepatomegaly, or splenomegaly. Cardiovascular exam was unremarkable. There were diminished breath sounds with dullness to percussion to the mid lung fields on the right. A spiral CT scan showed a large right pleural effusion and moderate abdominal ascites. Thoracentesis revealed milky white fluid which with a triglyceride level of 2093 mg/dL. A paracentesis revealed a triglyceride level of 468 mg/dL. Lymphoscintigraphy verified an abdominal origination of the chylous fluid. A bone marrow biopsy revealed normal marrow, without evidence of CLL. Urine collection revealed 3.23 grams of protein in 24 hours. Other etiologies of chylous ascites were excluded, and she was diagnosed with chylothorax due to chylous ascites resulting from nephrotic syndrome. Cidofovir, a known cause of nephrotic syndrome, was discontinued, and the chylothorax resolved. A repeat 24 hour urine collection 27 days later revealed 0.97 grams of protein.
DISCUSSIONS: Up to 50% of patients receiving cidofovir in clinical trials developed proteinuria or a significant reduction in creatinine clearance. In a recent trial evaluating cidofovir for adenovirus infection after stem cell transplantation, 9% of patients developed proteinuria. In the largest case series of nephrotic syndrome with ascites, 30 patients underwent paracentesis 2. 52% had chylous or milky peritoneal fluid. The mechanism of chylous ascites in nephrotic patients remains unclear. One theory holds that the hypercoagulable state of nephrotic syndrome results in vena cava thrombosis and secondary lymphatic obstruction. Another suggests that bowel edema from hypoalbuminemia changes the permeability of mucosal lymphatics, resulting in leakage of chylomicrons into the peritoneal space. Once chyle is present in the peritoneal space, it is free to transfer through diaphragmatic defects aided by negative intrathoracic pressure during inspiration. Extensive evaluation in this case failed to reveal a more common cause of chylothorax. Onset chronologically followed initiation of cidofovir and was associated with nephrotic syndrome. Resolution followed reduction in proteinuria after discontinuation of the drug.
CONCLUSION: Chylous ascites is a well described complication of the nephrotic syndrome. We report a rare case of nephrotic syndrome as a cause of chylothorax. In patients with nephrotic syndrome and chylothorax, investigation for an abdominal origin of chylothorax has important clinical implications, as exploration of the chest for diagnosis may be avoided.
DISCLOSURE: Joel Mermis, No Financial Disclosure Information; No Product/Research Disclosure Information