The Successful Use of Octreotide in the Treatment of Traumatic Chylothorax

Abstract

Chylothorax is a well-documented complication of thoracic trauma and is associated with mortality rates of up to 75%. The conservative treatment of chylothorax includes pleural drainage and a low-fat diet rich in medium-chain fatty acids, followed by total parenteral nutrition and nothing by mouth. If these measures fail and drainage continues to exceed 1 L/d, surgical thoracic duct ligation is usually recommended. However, many patients are unable to undergo this surgical procedure and require an alternative treatment. We present the cases of 2 adult patients, one of whom developed chylothorax after an elective surgical procedure, and the other after a traffic accident that caused multiple injuries. In both patients, conservative management with the addition of octreotide was successful and negated the need for surgical intervention.

Chylothorax is a rare, yet well recognized, complication of cardiothoracic surgery and non-operative thoracic trauma. Conservative treatment includes pleural drainage and a low-fat diet that is rich in medium-chain fatty acids (MCFA), followed by total parenteral nutrition (TPN) and nothing by mouth (NPO). If these measures fail and drain output continues to exceed 1 L/d, surgical thoracic duct ligation is usually recommended.

The use of octreotide in the conservative treatment of chylothorax after pediatric surgery is well recognized,¹ and several case reports support its use to treat chylothorax in adults. However, there have been no clinical trials to support the use of octreotide in adults with chylothorax secondary to operative or non-operative trauma. We present the cases of 2 adults in whom conservative treatment of chylothorax was successful with the addition of octreotide.

Case Reports

Patient 1

A 67-year-old man with suspected non-small cell lung cancer was admitted to our institution for an elective right French window thoracotomy, wedge resection of his right lower lobe, and lymph node excision. Postoperatively, his chest drainage was serosanguineous until postoperative day 2, when the fluid turned “milky”; on that day, 1.4 L of this fluid was collected through the chest drain. Biochemical analysis revealed a fluid triglyceride level of 8.7 mmol/L and a serum triglyceride level of 1.5 mmol/L; therefore, a diagnosis of chylothorax was made, and the patient was placed on an MCFA diet. Despite the dietary change, drainage of the turbid white fluid continued, and the patient's albumin level began to drop. On postoperative day 7, his albumin level was 22 g/L and the fluid drainage continued to exceed 1 L/d, so we started him on an NPO and TPN regimen. We also began giving the patient subcutaneous octreotide, 200 µg 3 times a day.

Drainage of the milky fluid gradually decreased to 150 mL on day 9. On the 10th postoperative day, 3 days after the beginning of octreotide therapy, the fluid became translucent. The patient's albumin level continued to drop despite TPN and was as low as 16 g/L on postoperative day 11. However, his albumin level started to increase over the next 4 days, so a fat-free diet was introduced. Ten days after the beginning of octreotide therapy, the patient's drainage of serous fluid was 150 mL/d. Octreotide treatment was stopped on postoperative day 17, and the patient was discharged from the hospital on day 18 with an atrial drain in place. This drain was removed on postoperative day 21 after the drainage of fluid had ceased. At 1 year, he remained well and was having no long-term complications.

Patient 2

A 50-year-old man was admitted to the hospital after a traffic accident. He had multiple injuries, including fractured vertebrae (T10 and L1 through L5) and a fracture dislocation of L5 and S1, leading to an incomplete Brown-Séquard syndrome, retroperitoneal hematoma, left pneumothorax, and a large right hemothorax. The pneumo- and hemothoraces were drained in the emergency room, and 225 mL of blood drained when the right chest drain was placed. The patient was transferred to the intensive care unit for further treatment.

In the days following his admission, the fluid from the right drain was hemoserous but slightly cloudy. The volume was 575 mL, 1,180 mL, 580 mL, and 570 mL per day during the first 4 days. Results of biochemical analysis showed a triglyceride level of 2.5 mmol/L and a cholesterol level of 1.3 mmol/L—a combination that indicated chylothorax. The patient was started on an NPO and TPN regimen. Thoracic duct ligation was considered but was not possible, because the lateral decubitus position would have been too dangerous for the patient, given the unstable nature of his vertebral fractures.

The drainage continued to exceed 800 mL/d, and the albumin level decreased from 38 g/L on admission to 16 g/L 13 days later. Therefore, octreotide treatment was begun subcutaneously at a dosage of 50 µg 3 times a day. The effects were immediately evident: the drainage decreased to 70 mL in total for the first 3 days of treatment and then to 3, 5, 0, and 2 mL for the next 4 days. On the 4th day of octreotide treatment, a nasogastric feeding tube was inserted and an MCFA diet was started. Four days later, the chest drain was removed and the chest radiograph was clear. The albumin level had increased to 28 g/L.

Discussion

The term chylothorax refers to the presence of lymphatic fluid (chyle) in the pleural space secondary to leakage from the thoracic duct or one of its main tributaries.² The most common causes are thoracic trauma of surgical or nonsurgical origin, neoplasms (most commonly lymphoma), and some infections, including tuberculosis. Chylothorax occurs in less than 1% of thoracic procedures, and its prevalence ranges from 0.5% to 2%.³ The incidence seems to be much higher in cases of esophagectomy with mediastinal lymphadenectomy (3%) than after pulmonary resection (0.4%).⁴ Regardless of the cause, chylothorax is associated with high morbidity and mortality rates, mainly related to dehydration, malnutrition, and immunologic compromise. Mortality rates as high as 75% have been reported.⁵

The thoracic duct is the common trunk of all the lymphatic vessels in the body. It begins in the abdomen at the cisterna chili, enters the thorax at the aortic hiatus of the diaphragm, and ascends through the posterior mediastinum behind the aorta. At the level of the 5th vertebra, it moves to the left side, ascending behind the aortic arch and the left subclavian artery, opening into the angle of the junction between the left subclavian vein and left jugular vein. It is therefore easy to see why injuries above and below the level of the 5th vertebra cause left- and right-sided chylothorax, respectively. The thoracic duct transports 60% to 70% of ingested fat to the bloodstream; the usual concentration of fat in chyle is 0.4 to 6 g/dL.⁶ Chyle also contains proteins, white blood cells, electrolytes, coagulation factors, and large amounts of fluid.

Diagnosis of chylothorax can be made clinically—especially in the presence of the characteristic milky fluid in high-risk patients. However, a fasting patient may have serous-appearing fluid but not chylothorax, and chylothorax must be distinguished from empyema and chyliform effusion. Diagnosis is confirmed by the biochemical composition of the pleural fluid aspirated. With a triglyceride level of >110 mg/dL, there is a 99% chance that the fluid is chyle, whereas a level <50 mg/dL indicates only a 5% chance. A fluid cholesterol-to-triglyceride ratio of <1 is also diagnostic.²

The current management options for chylothorax are conservative, surgical, or the two in combination. Conservative treatment includes, initially, pleural drainage, along with an MCFA diet, escalating to TPN and NPO if drainage fails to abate. Conservative treatment should always be considered, because thoracic duct leaks close spontaneously in nearly 50% of patients.² The MCFA diet is used because these fatty acids are absorbed directly into the portal venous system, rather than into the intestinal lymphatic system, thus reducing the amount of chyle produced. In 1964, Hashim and colleagues⁷ were the first to describe an MCFA diet as treatment for chylous fistulas. Due to the composition of chyle, high losses of this fluid require active monitoring of patients' nutritional status. A decision must be made early to begin TPN if the drainage continues despite an MCFA diet.

Octreotide can be added when other conservative methods are inadequate. Octreotide is a long-acting somatostatin analog used for the relief of symptoms associated with functional gastroenteropancreatic endocrine tumors and for symptomatic control in acromegaly. It is used in the treatment of chylothorax, because it acts directly on vascular somatostatin receptors to minimize lymphatic fluid excretion. In addition, octreotide increases splanchnic arteriolar resistance and decreases gastrointestinal blood flow, indirectly reducing lymphatic flow.⁸

Surgery is recommended if chyle drainage persists for more than 3 weeks, if the daily fluid loss exceeds 1.5 L, or if there is imminent nutritional complication in debilitated patients.⁹ The mainstay of surgical intervention is thoracic duct ligation at the level of the diaphragm, which has a success rate of 80% at best.⁴ Minimally invasive techniques such as video-assisted thoracoscopic surgery have been performed successfully for thoracic duct ligation.¹⁰ Open thoracotomy is another common method. In both techniques, the duct is ligated between the 8th and 12th vertebrae. However, there are occasions when control of a chyle leak can be difficult through a thoracic approach, and an abdominal approach to ligation of the thoracic duct at the level of the diaphragmatic hiatus has been reported.¹¹

In each of our patients, octreotide was begun after failure of an MCFA diet and an NPO and TPN regimen to stop the chyle leak. The addition of this drug caused an immediate decrease in drainage without any side effects in either patient. There is no evidence in the medical literature to confirm the effectiveness of octreotide. However, in light of the inherent risks of surgery, we believe that initial conservative management with octreotide should be considered in patients with chylothorax. This combined therapy can be of particular value in such patients who are at high risk for surgery.