Primary nephrotic syndrome complicated by chylothorax: a case report.

Chylothorax is an uncommon and serious clinical condition, typically induced by trauma, either postsurgical or accidental injury, but the mechanism of chylothorax caused by nephrotic syndrome is still unclear. Here, we report a case of primary nephrotic syndrome with membranous nephropathy (MN) in a 66-year-old man who presented with severe chylothorax. The chylothorax was managed by intercostal chest tube drainage, subcutaneous injection of enoxaparin, and treatment with anti-inflammatory agents and diuretics. After treatment, the patient's pleural effusion decreased, and the chyle gradually became clear. We discuss the causes of MN with chylothorax. We considered that the hypoproteinemia changed the permeability of mucous membranes and lymphatic vessels, leading to leakage of chylous particles and chylous pleural effusion formation. Chylothorax may also have been caused by severe tissue edema, edema of the lymphatic walls, and increased pressure, resulting in increased permeability or rupture of the lymphatic wall, and leakage of chylous fluid into the thoracic cavity. Because of its rarity, we hope this case report will improve clinicians' understanding of MN complications in primary nephrotic syndrome and provide suitable treatment options for future clinical reference.