[Chylothorax and the pathology of the lymphatic pleura]

The diagnosis of chylous effusions of the pleura hardly poses any problems if one carefully differentiates the true chylothorax rich in triglycerides from chylous effusions rich in cholesterol and poor in triglycerides. The pathology of chylothorax requires a double breach of both thoracic duct and pleura. The causes are dominated by complications of thoracic surgery direct trauma, closed chest injuries and malignant mediastinal tumours. Other rarer causes raise the difficult problem of the spontaneous chylothorax. Even the idea of an idiopathic chylothorax is controversial and makes one suspect the rupture of a previously fragile thoracic duct, following apparently minimal trauma. Treatment is not yet standardised but requires strict rest, and a medium chain triglyceride diet, correction of fluid and electrolyte balance and careful nutrition. Surgery, generally delayed for a few weeks, may lead to the repair of a lymphatic leak, localised by a biological tracer or a contrast material; sometimes only a ligature at the base of the thoracic duct will dry up the effusion. The prognosis still remains mediocre and is dominated by the cause, notably when this is a tumour and also by the localised or diffuse character of the lymphatic disturbance.