| Patient Education |
|
Click here for patient education.
|
|
You are in: eMedicine Specialties >
Gastroenterology > Systemic Disease
Chylothorax
Article Last Updated: Feb 21, 2007
AUTHOR AND EDITOR INFORMATION
Section 1 of 10  
Author: Rosemary Kozar, MD, PhD, Assistant Professor, Department of Surgery, Division of General Surgery, University of Texas at Houston School of Medicine
Rosemary Kozar is a member of the following medical societies: Society of University Surgeons
Coauthor(s):
Sasha D Adams, MD, Resident Physician, Department of Surgery, University of Texas at Houston School of Medicine;
James Cipolla, MD, Staff Physician, Department of Surgery, Maimonides Medical Center
Editors: Mounzer Al Al Samman, MD, Department of Internal Medicine, Division of Gastroenterology, Assistant Professor, Texas Tech University School of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; BS Anand, MD, Department of Internal Medicine, Division of Gastroenterology, Professor, Baylor University College of Medicine; Alex J Mechaber, MD, FACP, Assistant Dean for Medical Curriculum, Associate Professor of Medicine, Division of General Internal Medicine, University of Miami Miller School of Medicine; Julian Katz, MD, Clinical Professor of Medicine, Drexel University College of Medicine; Consulting Staff, Department of Medicine, Section of Gastroenterology and Hepatology, Hospital of the Medical College of Pennsylvania
Author and Editor Disclosure
Synonyms and related keywords:
thoracic duct leak, pleural chyle, pleural effusion, lymphoma, thoracic duct ligation, pleuroperitoneal shunt, pleurodesis, pleurectomy, chyle, pleural space, postesophagectomy chylothorax, thoracentesis, lymphatic fluid, thoracic duct injury, loculated chylothorax
Background
Chylothorax refers to the presence of lymphatic fluid in the pleural space secondary to leakage from the thoracic duct or one of its main tributaries. In 1875, H. Quinke described the first traumatic chylothorax. In 1948, R.S. Lampson performed the first thoracic duct ligation.
Pathophysiology
A tear or leak in the thoracic duct causes chylous fluid to collect in the pleural cavity, which can cause acute or chronic alterations in the pulmonary mechanics. In a normal adult, the thoracic duct transports up to 4 L of chyle per day, allowing a rapid and large accumulation of fluid in the chest.
Frequency
International
The prevalence after various cardiothoracic surgeries is 0.2-1%.
Mortality/Morbidity
Mortality and morbidity rates are approximately 10% in major clinical medical centers.
Sex
Chylothorax has no predilection for either sex.
Age
Chylothorax has no predilection for age.
History
- Usually, the patient remains asymptomatic until a large amount of chyle accumulates in the pleural space.
- The average latent period between the insult and the onset of symptoms is 7-10 days. Symptoms include the following:
- Rarely, patients may experience a rapid accumulation of fluid in the pleural space, causing a tension chylothorax. This is of particular concern following a pneumonectomy. These patients experience a rapid hemodynamic and respiratory compromise, similar to classic tension pneumothorax.
Physical
- Findings on examination are nonspecific and include the following:
- Decreased breath sounds
- Shifting dullness
- If the patient has an existing chest tube, excess drainage of 400-600 cc per 8-hour period is concerning for a chylous leak, particularly in postsurgical patients.
Causes
- Nontraumatic
- Malignant etiologies account for more than 50% of chylothorax diagnoses and are separated into lymphomatous and nonlymphomatous. Lymphoma is the most common cause, representing about 60% of all cases, with non-Hodgkin lymphoma more likely than Hodgkin lymphoma to cause a chylothorax. By comparison, nonlymphomatous causes are rare.
- Nonmalignant etiologies are separated into idiopathic, congenital, and miscellaneous.
- Clinicians must rule out all possible malignant causes before designating the chylothorax as idiopathic.
- Congenital chylothorax is the leading cause of pleural effusion in neonates.
- Miscellaneous causes include cirrhosis, tuberculosis, sarcoidosis, amyloidosis, and filariasis.
- Traumatic
- Trauma is the second leading cause of chylothorax (25%).
- Iatrogenic injury to the thoracic duct has been reported with most thoracic procedures. In particular, cardiothoracic surgery has been associated with 69-85% of cases of chylothorax in children.
- Nonsurgical traumatic injury is a rare cause, usually secondary to penetrating trauma.
- Pseudochylothorax
- Chylothorax must be distinguished from pseudochylothorax, or cholesterol pleurisy, which results from accumulation of cholesterol crystals in a chronic existing effusion.
- The most common cause of pseudochylothorax is chronic rheumatoid pleurisy, followed by tuberculosis and poorly treated empyema.
Empyema, Pleuropulmonary
Hemothorax
Other Problems to be Considered
AIDS-related complex
Congestive heart failure
Exudative pleural effusion
Malignant pleural effusion
Pseudochylothorax
Lab Studies
- The following laboratory studies are not required for diagnosis but are useful to determine the metabolic and nutritional status of the patient:
- Serum electrolyte tests
- Serum albumin test
- CBC count with differential to look for lymphocyte depletion
Imaging Studies
- Chest radiographic findings are nonspecific for chylothorax and indistinguishable from other causes of pleural effusion.
- Determine if effusion is bilateral.
- Look for a mediastinal shift.
- If the etiology of the chylothorax is unknown, obtain CT scans of the chest and abdomen to rule out malignancy.
- Lymphangiography is useful when the anatomy of the thoracic duct needs to be defined preoperatively or when the site of the leak is not clinically obvious.
Procedures
- Thoracentesis and pleural fluid analysis are the criterion standards to establish a diagnosis of chylothorax. Alternatively, in a postsurgical patient, tube thoracostomy output can be analyzed.
- Pleural fluid analysis for triglyceride content helps to confirm a diagnosis of chylothorax.
- A level greater than 110 mg/dL reflects a 99% chance that the fluid is chyle.
- A level less than 50 mg/dL reflects only a 5% chance that the fluid is chyle.
- If the level is 50-110 mg/dL, use lipoprotein analysis to inspect the pleural fluid for chylomicrons or cholesterol crystals.
- A ratio of pleural fluid cholesterol to triglyceride of less than 1 is also diagnostic.
- A fasting patient may have serous-appearing pleural fluid. To confirm the diagnosis, administer cream through a nasoenteric tube prior to fluid collection. The cream will change the chylous production from serous to the characteristic milky white fluid. This change is diagnostic for a chyle leak.
- Chylothorax can be distinguished from pseudochylothorax by fluid analysis. In pseudochylothorax, the cholesterol level is greater than 200 mg/dL, no chylomicrons are present, and cholesterol crystals are seen at microscopy.
Medical Care
Patients with chylothorax can be treated by conservative means or surgery. Certain principles are common to both treatment options, including treating the underlying cause, decreasing chyle production, draining and obliterating the pleural space, providing appropriate fluid and nutritional replacement, and instituting necessary respiratory care.
- Always consider conservative management because the thoracic duct leak closes spontaneously in nearly 50% of patients. Few or no symptoms and minimal chyle loss characterize these cases.
- Decompress the pleural space with tube thoracostomy or repeated thoracentesis to keep the lung expanded against the chest wall and mediastinum.
- Reduce chyle production by instituting total parenteral nutrition or a fat-restricted oral diet supplemented with medium-chain triglycerides.
- Chemoradiation may promote resolution of chylothorax and should be used in patients with malignant chylothorax who are not surgical candidates.
- Somatostatin, or its analogue octreotide, has been used with success in a number of pediatric cases of postoperative and iatrogenic chylothorax. Reported effective doses of intravenous somatostatin range from 3.5-12 mcg/kg/h. Care must be taken to watch for adverse effects of somatostatin therapy, including diarrhea, hypoglycemia, and hypotension.
Surgical Care
The timing of surgical management is controversial and depends on the etiology of the chylothorax and the patient's overall condition. Preoperatively, localize the thoracic duct leak by means of lymphangiography, oral administration of cream, or injection of 1% Evans blue dye. Cream is high in long-chain fatty acids and works by increasing chyle flow. It is administered enterally at 60-90 mL/h for 3-6 hours until a change in the color of the pleural fluid is noted. Evans blue dye can either be injected into the web space of the toes for uptake into the lymphatic space or be added to cream to increase visualization.
- Indications for surgical intervention include the following:
- Chyle leak greater than 1 L/d for 5 days or a persistent leak for more than 2 weeks despite conservative management
- Nutritional or metabolic complications, including electrolyte depletion and immunosuppression
- Loculated chylothorax, fibrin clots, or trapped lung
- Postesophagectomy chylothorax (Patients with this carry a high mortality rate if treated conservatively.)
- Surgical options depend on the site of injury and the etiology of the chylothorax.
- Thoracic duct ligation is the criterion standard. The duct is usually ligated between the eighth and twelfth thoracic vertebrae, just above the aortic hiatus. The approach is usually through the right chest, either by an open right thoracotomy or through a thoracoscope.
- A pleuroperitoneal shunt can be successful for refractory chylothorax but can be complicated by infection and obstruction.
- Pleurodesis is often used for malignant chylothorax, but it will not work in a case of loculated chylothorax or a trapped lung.
- Surgical pleurectomy is a treatment option.
Complications
- Malnutrition
- Immunosuppression
Medical/Legal Pitfalls
- The timing of surgical management is controversial and depends on the etiology of the chylothorax and the patient's overall condition.
- Patients with postesophagectomy chylothorax have a 50-82% mortality rate if treated conservatively.
- A malignant etiology of the chylothorax must be ruled out, as greater than 50% of cases are due to malignancy, of which lymphoma accounts for approximately 75% of cases, followed by lung carcinoma.
| Media file 1:
Anteroposterior upright chest radiograph shows a massive left-sided pleural effusion with contralateral mediastinal shift. Image courtesy of Allen R. Thomas, MD. |
 |  View Full Size Image | |
Media type: X-RAY
|
| Media file 2:
A CT scan of the chest of a 3-year old child showing left side effusion and underlying parenchymal infiltrate and atelectasis. Image courtesy of Ibrahim Abdulhamid, MD. |
 | View Full Size Image | |
Media type: CT
|
- Ammori JB, Pickens A, Chang AC. Tension chylothorax. Ann Thorac Surg. Aug 2006;82(2):729-30.
- Browse NL, Allen DR, Wilson NM. Management of chylothorax. Br J Surg. Dec 1997;84(12):1711-6. [Medline].
- Clarke SA, Lakhoo K, Sherwood W. Somatostatin for intractable postoperative chylothorax in a premature infant. Pediatr Surg Int. May 2005;21(5):390-1. [Medline].
- Hillerdal G. Chylothorax and pseudochylothorax. Eur Respir J. May 1997;10(5):1157-62. [Medline].
- Maskell NA, Butland RJ. BTS guidelines for the investigation of a unilateral pleural effusion in adults. Thorax. May 2003;58 Suppl 2:ii8-17.
- Merrigan BA, Winter DC, O'Sullivan GC. Chylothorax. Br J Surg. Jan 1997;84(1):15-20. [Medline].
- Mohseni-Bod H, Macrae D, Slavik Z. Somatostatin analog (octreotide) in management of neonatal postoperative chylothorax: is it safe?. Pediatr Crit Care Med. Jul 2004;5(4):356-7. [Medline].
- Ogi S, Fukumitsu N, Uchiyama M. A case of chylothorax diagnosed by lymphoscintigraphy using Tc-99m HSA-DTPA. Clin Nucl Med. Jun 2002;27(6):455-6. [Medline].
- Paes ML, Powell H. Chylothorax: an update. Br J Hosp Med. May 4-17 1994;51(9):482-90. [Medline].
- Postma GN, Keyser JS. Management of persistent chylothorax. Otolaryngol Head Neck Surg. Feb 1997;116(2):268-70. [Medline].
- Rice TW, Milstone AP. Chylothorax as a result of chronic lymphocytic leukemia: case report and review of the literature. South Med J. Mar 2004;97(3):291-4. [Medline].
- Sieczka EM, Harvey JC. Early thoracic duct ligation for postoperative chylothorax. J Surg Oncol. Jan 1996;61(1):56-60. [Medline].
- Valentine VG, Raffin TA. The management of chylothorax. Chest. Aug 1992;102(2):586-91. [Medline].
- Vallieres E, Shamji FM, Todd TR. Postpneumonectomy chylothorax. Ann Thorac Surg. Apr 1993;55(4):1006-8. [Medline].
- Wemyss-Holden SA, Launois B, Maddern GJ. Management of thoracic duct injuries after oesophagectomy. Br J Surg. Nov 2001;88(11):1442-8. [Medline].
Chylothorax excerpt Article Last Updated: Feb 21, 2007
|
