Abstract
The use of somastostatin and its analogues in the treatment of chyle fistula is a new approach and has been documented in a few cases. In this study, we present the case of a male patient with chyle fistula that was stopped completely within 24 hours after the somatostatin therapy.
1
Case report
A 42-year-old man was referred to the general surgery department because he had swelling in the supraclavicular side and aching neck for 1 year. Physical examination revealed the thyroid was larger than normal, and the detected mass was tender and fixed to the underlying tissue in the left supraclavicular side. Ultrasound, computed tomography, and magnetic resonance imaging with contrast revealed multinodulary growth in the thyroid lobe, and a number of lymph nodes were detected in the left supraclavicular side and in the left jugular vein.
The patient subsequently underwent a total thyroidectomy and modified radical left neck dissection. During neck dissection, thoracic duct injury occurred. In the operation site, milk fluid appeared. The ductus thoracicus was identified, and chyle leakage was controlled by vascular clips and was oversewn. Leakage from the thoracic duct was not observed until the end of the operation. Drain with negative pressure was placed.
After the second postoperative day, the patient was tolerating a full oral diet; a moderate quantity of milky fluid appeared from the drain site in the neck area. In the patients with suspected postoperative chyle leakage, oral diet was stopped and total parenteral nutrition (TPN) was started. Daily drain output was 450 mL. Drainage fluid was biochemically analyzed. This analysis revealed a triglyceride level of 638 mg/dL. On postoperative day 8, somatostatin 3.5 μ g/kg per hour (250 μ g) infused within 12 hours (total 3 mg/d) was started. Within 24 hours, the chyle fistula stopped draining completely. Patient received a total 5 days of somatostatin treatment. On postoperative day 15, the patient was started on oral diet, and on postoperative day 19, patient was discharged home in a stable condition.
2
Discussion
Chyle fistula resulting from violation of the thoracic duct or right lymphatic duct during neck dissection is a rare complication with potentially serious morbidity. It occurs 1%–2.5% after neck dissection, with most occurring on the left side . Moreover, it has also seen after penetrating neck trauma, cervical node biopsy, and cervical rib resection . The thoracic duct terminates in the angle of the junction of the left internal jugular and subclavian veins. However, the draining channels are highly variable and the vessels often ramify into multiple vessels. The major lymphatic duct in the lower neck lateral to the carotid sheath is the most common site of injury during lateral neck dissection . Chyle fistulas are significant in that they can impair nutrition, cause metabolic disturbances, compromise and delay wound healing, result in skin flap necrosis, and prolong hospitalization. The best treatment of chyle fistula is prevention. Chyle leakage may be more manageable when found during or at the end of operation. The thoracic duct identified during neck dissection is ligated with 3-0 or 4-0 nonabsorbable sutures with minimal manipulation. Although unexpectedly high volumes of drain fluid on the first or second postoperative day may be a sign of chyle leakage, it may be confused with a high-output condition of drainage fluid not associated with chyle leakage. Measurement of triglyceride concentrations in drainage fluid may assist in the early detection of postoperative chyle leak. Drainage fluid triglyceride concentration of more than 100 mg/dL or greater serum concentration is thought to support a diagnosis of chyle fistula. If fistula was detected after operation and in the daily volume of the neck drainage, exceeding 600 mL, conservative treatment studies are unsuccessful.
Medical management is the first line of treatment to reduce chyle flow. These measures include allowing adequate drainage, applying pressure dressing, serial aspiration, bed rest, and nutritional modifications. Nutrition can be provided enterally with an elemental diet supplemented with medium-chain triglycerides that are absorbed directly into the portal circulation, by-passing the lymphatic system. In serious cases, TPN should be performed. Total parenteral nutrition is an alternative dietary modification line and the increased costs make TPN a second-line approach at most institutions. Otherwise, remaining fluid and electrolyte of patients are impaired. Conservative treatment should be limited to about 30 days. The indication for surgical intervention is controversial, but persistent output of more than 600 mL/d chyle leakage for several days despite medical therapy or extremely high output (>2 L) is an appropriate indication. Surgical intervention includes closing the leak site with fibrin glue, a pedicled muscle flap, or other absorbable mesh. Minimally invasive thoracoscopic ligation of the thoracic duct may be used to treat persistent high-output chyle leaks refractory to repeated surgical and medical interventions. In our case, conservative treatment was applied because at the second postoperative day, fistula was present after oral nutrition was applied and daily drain was 450 mL.
Somatostatin is a peptide that acts both as a neurohormone and a paracrine agent. Its biological actions are extremely diverse and include the inhibition of thyroid-stimulating hormone, growth hormone, vasoactive intestinal peptide, gastrin, motilin, insulin, glucagon, intestinal secretion, and bile flow. The exact mechanisms of somatostatin on drying lymphatic fistulas are not completely understood. It has been previously shown that, to decrease the intestinal absorption of fats, triglyceride concentration in the thoracic duct should be lowered and lymph flow in the major lymphatic channels should be attenuated. In the context of chyle fistulas, somatostatin’s effectiveness may be because of its ability to reduce gastric, pancreatic, and intestinal secretion; inhibit motor activity of the intestine; slow the process of intestinal absorption; reduce splanchnic blood flow; and decrease hepatic venous pressure. It has been demonstrated that in the lymph that in serum in dogs, somatostatin has decreased the thoracic duct lymph flow rate and the ratio of triglycerides . Somatostatin and its synthetic analogues are effective in neuroendocrine tumor hyperfunction, pituitary tumors, pancreatic fistulas, and high output enterostomies. Abdominal discomfort and decreased fat absorption are the less dramatic side effects. In developed chyle fistulas from neck dissection treatment, using somatostatin and its synthetic analogues is limited by a few cases. However, other case reports have documented their usefulness in the treatment of chylothorax . There was a marked decrease in chyle production within 24 hours of starting therapy and no observed side effects for all of these patients. In our patients, chyle fistula was stopped completely within 24 hours after the somatostatin therapy. This permitted the resumption of regular oral diet within days of instituting. The rapid response and minimal side effect profile make somatostatin an attractive addition to the medical management of a chyle fistula . Earlier institution of somatostatin therapy may reduce costs and patients’ morbidity. Further studies are needed to confirm this observation.
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