eMedicine Specialties > General Surgery > Abdomen

Chyle Fistula

Author: Deron J Tessier, MD, Staff Surgeon, Kaiser Permanente Medical Center, Fontana, CA
Coauthor(s): Russell A Williams, MBBS, Program Director, Professor, Department of Surgery, University of California Medical Center at Irvine
Contributor Information and Disclosures

Updated: Jan 10, 2008

Introduction

Chyle fistula is defined as a leakage of lymphatic fluid from the lymphatic vessels, typically accumulating in the thoracic or abdominal cavities, but occasionally manifesting as an external fistula. Chyle fistula is a rare but potentially devastating and morbid condition. First described in the 17th century as complications of trauma, chyle fistulas most commonly occur secondary to lymphatic disease or malignancy or following abdominal, neck, or thoracic operations. Chyle fistulas also can form as a result of venous hypertension, and they have been described in patients with superior vena cava syndrome or thrombosis of the vena cava, among others.

History of chyle fistulas

• 17th century: Trauma is recognized as a primary cause of chylous fistulas.
• 1627: Asellius first describes chyle from the mesenteric vessels of a dog.
• 1691: Morton describes chylous ascites after performing paracentesis in an 18-month-old child.
• 1854: Virchow publishes an account of chylous ascites in a newborn calf with occlusion of the subclavian vein.

History of the Procedure

Patients with chyle fistulas usually give histories of some comorbid conditions such as malignancy or prior operations in the chest, neck, or abdomen. In postoperative patients, symptoms become evident after the start of oral feeding and depend on the site of obstruction.

Problem

Chyle fistulas can be extremely morbid due to loss of fluids, electrolytes, and other nutrients. In addition, chyle fistulas can result in loss of lymphocytes and immune dysfunction. Finally, chyle fistulas are space-filling and exert pressure on surrounding tissues, creating symptoms that can range from minimal discomfort to life-threatening situations.

Frequency

Chyle fistulas are rare events. Typical causes include lymphatic disease; malignancy; trauma; and postoperative trauma following abdominal, neck, or thoracic operations. Postoperatively, approximately 75% of chyloperitoneum cases occur after abdominal aortic aneurysm repair, 19% after aortofemoral bypass, and 7% after resection of infected aortic grafts.

Etiology

The most common causes of chyle fistulas include subclavian vein thrombosis, malignant invasion of the lymphatics, inflammatory reactions (ie, tuberculosis, pancreatitis, cirrhosis, adhesions, pulmonary fibrosis), and prior surgeries near the cisterna chyli or thoracic duct.

Pathophysiology

Leakage of lymph from damaged lymph vessels is common after surgery or trauma. However, damaged lymphatics most often heal spontaneously or direct lymph centrally via rich interconnected lymphatic collaterals, without any significant morbidity. For chyle fistulas to form, either a scarcity of lymphatic collaterals must be present or the injury to the lymphatic channels must overwhelm the remaining lymphatic vessels. In addition, abnormal lymphatic vessels may be incapable of adequate lymph flow, leading to the accumulation of chyle.

Chyle flow varies dramatically depending on the quantity and quality of oral intake. During times of starvation, chyle flow is minimal. After meals, especially those with high contents of long-chain fatty acids, chyle flow increases dramatically. This basic knowledge provides the rationale for controlling dietary intake as part of the treatment of this disease.

Presentation

Because of the relatively low incidence of chyle fistulas, a high index of suspicion is required to make a timely diagnosis. Diagnosis usually is made after the patient has recovered from the injury and has started eating.

Symptoms of chyloperitoneum include (1) nausea, (2) vomiting, (3) early satiety or anorexia, (4) abdominal discomfort or pain, and (5) dyspnea due to chylous fluid causing abdominal distention and pressure on the visceral structures and diaphragm.

Symptoms of chylothorax include (1) shortness of breath, (2) pleural effusion, and (3) decreased cardiac preload due to a mediastinal shift from a large chylothorax.

Indications

Characteristics of thoracentesis or paracentesis aspirate

• Odorless
• Milky appearance that separates into a creamy layer when left to stand
• Specific gravity greater than 1.012
• Total fat composition of 0.4-4 g/L
• Total protein greater than 30 g/L
• pH greater than 7.0
• Sterile fluid
• Lipophilic globules when stained with Sudan III
• WBC differential of predominately lymphocytes

Relevant Anatomy

The cisterna chyli and thoracic duct drain lymph from the entire body except the head, neck, arms, and right thorax (which instead use the right bronchomediastinal, jugular, and subclavian lymph trunks to form the right lymph duct). The anatomy is highly variable, with 50% of people not having an identifiable cisterna chyli. In addition, half of the 4 liters of lymph draining through the cisterna chyli and thoracic duct originates from the intestinal and hepatic lymphatics.

The cisterna chyli is found on the posterolateral edge to the right of the aorta at the level of vertebral bodies T12, L1, L2, and L3 as lymphatics from the mesentery, intercostal, and lumbar regions coalesce in the retroperitoneal space.

At approximately L1, the cisterna chyle ascends, becoming the thoracic duct. The duct then enters the posterior mediastinum, crosses at T4 into the left retropleural space, and continues in a cephalad direction. The thoracic duct then enters the venous system at the junction of the left subclavian and internal jugular veins (see Media file 1).

Contraindications

Contraindications to surgical correction of chyle fistulas are based on the patient's comorbidities and his or her ability to tolerate surgery.

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