Chylothorax is a pathological accumulation of lymphatic (chyletic) fluid in the pleural cavity resulting from lymphorrhea from the thoracic duct. The development of disease is accompanied by shortness of breath, progressive deterioration of well-being, collapse, exhaustion, respiratory failure. Pathology is diagnosed according to clinical and anamnestic data, the results of radiography, thoracocentesis, cytological assessment of chyletic fluid, thoracoscopy. Treatment includes repeated punctures or drainage of the pleural cavity to remove the chylus, with persistent lymphorrhea – ligation of the thoracic lymphatic duct, pleuroperitoneal bypass surgery, pleurodesis, lymphovenous anastomosis, etc.
J94.0 Chylus effusion
Chylothorax is a rather rare pathology that develops as a result of a violation of the integrity of the thoracic lymphatic duct and the entry of lymphatic (chyletic) fluid circulating through it into the pleural cavity. Disease can be accompanied by significant lymphorrhea (lymph discharge) – up to 4-5 liters per day and lead to deep respiratory, metabolic and immunological disorders in the body that pose a threat to the patient’s life due to the loss of fats, proteins, vitamins, electrolytes, lymphocytes.
Pathology is observed in all age groups, including in newborns. In clinical practice, specialists in the field of thoracic surgery, traumatology, cardiac surgery, gastroenterology, oncology, phthisiology, phlebology and lymphology have to deal with chylothorax.
Chylothorax is a secondary disease or complication associated with the pathology of lymphatic vessels. Depending on the etiological factors, the following types are distinguished: congenital, traumatic and non-traumatic. Idiopathic chylothorax is also distinguished, developing in smokers with many years of experience. Possible reasons:
- Congenital pathologies. Chylothorax, manifested during the newborn and in childhood, may be due to hereditary atresia of the thoracic lymphatic duct, the presence of a fistula between its lower segment and the pleural cavity. With primary persistent fetal chylothorax, it is not always possible to establish an obvious cause of the disease (in rare cases, it may be hereditary lymphangiectasia).
- Iatrogenic injuries. Iatrogenic chylothorax develops with mechanical damage to the thoracic lymphatic duct or its main branches during surgical interventions (thoracic, cardiac surgery, abdominal, spinal), diagnostic procedures (translumbal arteriography, catheterization of the subclavian vein or left heart, esophagoscopy)
- Injuries. Traumatic chylothorax is the result of blunt trauma or penetrating injury to the chest and neck area. If the thoracic lymphatic duct is damaged, a left-sided chylothorax is formed above the level of the V–VI thoracic vertebrae, and a right-sided one is formed below. Idiopathic chylothorax is based on spontaneous rupture of the lymphatic vessel wall during coughing and increased pressure in the supraphragmatic region.
- Tumors. Chylothorax of non-traumatic genesis often occurs in the presence of various benign and malignant neoplasms affecting the lymphatic system of the mediastinum and neck (mediastinal malignant non-Hodgkin’s lymphoma, benign ductal lifangioma, mediastinal lymphangiomatosis, pleural cancer).
- Diseases of the thoracic and abdominal organs. Intra-thoracic tuberculosis and sarcoidosis, mediastinitis, ascending lymphangitis, amyloidosis, diaphragmatic hernia, etc. can lead to the development of chylothorax. Accumulation of chyletic fluid in the pleural cavity may be observed in the syndrome of the superior vena cava, accompanied by increased venous pressure and hypertension in the thoracic lymph duct system. Sometimes chylothorax can be the result of widespread chyletic ascites with combined lymphangioleiomyomatosis of the lungs, mediastinum, abdominal organs and retroperitoneal tissue.
Pseudochylothorax develops due to chronic pleural effusion (tuberculosis, rheumatoid arthritis). Pseudochylosis exudate has a cloudy milky-white color with a peculiar opalescent sheen and a high cholesterol content.
Chyletic fluid has a whitish color, contains a large number of chylomicrons, which are the main transport form of triglycerides, cholesterol and exogenous fatty acids. Chylomicrons are formed in the epithelial cells of the intestinal mucosa; after absorption through the lymphatic pathways, they enter the thoracic lymphatic duct and then into the circulatory system. In chylothorax, in addition to a high lipid content (more than 1.1 mmol / l), an excess of the total number of cellular elements (more than 1000 in ml) and lymphocytes (more than 90%) is observed in the pleural chylous exudate.
Postoperative chyletic pleurisy is characterized by gradual development: this is due to a gentle diet during the rehabilitation period, an insignificant amount of lymph, and its slow penetration into the pleural cavity. Therefore, postoperative chylothorax, as a rule, is recognized only 2-10 days after surgery. Clinical manifestations occur when the volume of chyletic effusion reaches 200 ml or more.
The first sign is shortness of breath, which, as the chylothorax increases, can progress to respiratory failure. There is heaviness in the corresponding half of the chest, tachycardia, hypotension, the development of a collaptoid state. Unlike exudative pleurisy, chest pains and hyperthermia are atypical for chylothorax, since lymph does not irritate the pleura and, due to its bacteriostatic properties, is able not to be infected for a long time.
Lymphorrhea up to 1.5-2 liters per day is critical, because a significant amount of protein, fats, electrolytes, and lymphocytes are lost along with the lymph. Prolonged or massive outflow of lymph causes the development of metabolic disorders and immunodeficiency, exhaustion of the patient, therefore it can lead to his death.
Physical data in chylothorax resemble signs of pleurisy. The dulling of the percussion sound and the weakening of breathing on the side corresponding to the lesion are determined. The data of the physical examination are clarified with the help of instrumental diagnostics:
- Radiation methods. Radiography of the lungs determines the presence of effusion in the pleural cavity, compression of the lung and displacement of the mediastinum. To find out the causes of chylothorax, it is necessary to perform ultrasound of lymphatic vessels, lymphangiography, lymphoscintigraphy and CT of the chest.
- Diagnostic pleural puncture. It is carried out on the basis of an X-ray picture and ultrasound data of the pleural cavity. With a chylothorax, a milky-white chyletic fluid is obtained. The analysis of pleural effusion reveals the oily nature of the exudate, the high content of lymphocytes, triglycerides, and the total number of cellular elements typical for lymph.
- Blood test. With chylothorax, lymphopenia and hypoproteinemia increase in the blood.
- Invasive diagnostics. To find out the exact cause of non-traumatic chylothorax, a biopsy of the lymph node, pleura, lung tissue, diagnostic thoracoscopy or mediastinoscopy with morphological examination of the biopsy material may be required.
Treatment begins with conservative methods: with their help, it is possible to achieve spontaneous termination of lymphorrhea in almost 50% of patients with low-symptomatic or asymptomatic chylothorax. With conservative management of the chylothorax, the pleural cavity is drained with the installation of permanent drainage or a series of pleural punctures with evacuation of the chyletic fluid. This results in decompression of the lung and mediastinal organs, reduction of respiratory disorders.
To reduce the production of chylus, the patient is completely transferred to parenteral nutrition or a high-calorie diet with fat restriction is prescribed. In order to correct hypoproteinemia and electrolyte disorders in chylothorax, infusion therapy with protein and salt preparations is carried out. Intravenous administration of somatostatin is successfully used for resorption of effusion.
With the failure of conservative measures and ongoing lymphorrhea, it is advisable to switch to surgical tactics. The main types of operations performed with chylothorax are:
- pleuroperitoneal bypass surgery;
- ligation of the thoracic lymphatic duct above and below the fistula;
- obliteration of the pleural cavity with talc (pleurodesis);
- the imposition of lymphovenous anastomosis.
Successful cases of lymphatic duct embolization in adult patients are described. With a chylothorax caused by a tuberculous process, specific treatment is indicated; with a tumor etiology, chemoradiotherapy is indicated.
Prognosis and prevention
Lethality in chylothorax ranges from 15 to 50%. Prognostically unfavorable course of chylothorax in malignant neoplasms of the thoracic cavity. With timely diagnosis and complex treatment of traumatic chylothorax, in most cases it is possible to achieve positive results.
Prevention of iatrogenic chylothorax consists in careful and justified diagnostic manipulations, invasive medical procedures, surgical interventions. In case of chest injuries, it is always necessary to remember about the possibility of damage to the thoracic lymphatic duct and the development of a chylothorax. Prevention of idiopathic chylothorax dictates the need to quit smoking.