Keywords
chylous ascites - chyle leak - lymphatic flap
Chylous ascites is a debilitating condition characterized by milky, triglyceride-rich
fluid accumulating in the peritoneal cavity due to disruption of the thoracic or intestinal
lymphatic system.[1] It is associated with severe malnutrition, immunosuppression, and mortality,[2] and unfortunately one-third of patients do not respond to medical therapies.[3] We present a rare case of massive chylous ascites and chylothorax secondary to chronic
pancreatitis in a patient who failed multiple medical therapies, and who was ultimately
successfully treated with a novel surgical lymphatic cable flap.
Case Report
A 59-year-old man with history of hypertension and prostate cancer status postremote
radical prostatectomy was referred to the Massachusetts General Hospital (MGH) for
management of chylous ascites and chylothorax secondary to severe pancreatitis that
likely damaged the cisterna chyli.
The patient had severe gallstone pancreatitis in September 2014, which required an
intensive care unit stay at an outside hospital, during which time he underwent a
laparoscopic cholecystectomy. He recovered well, but in April 2015, he developed dyspnea
and was found to have a large right-sided pleural effusion. He underwent thoracentesis,
with removal of 3 L of chyle. He had no abdominal pain; however, axial imaging demonstrated
extensive pancreatic necrosis consistent with his prior pancreatitis; portal vein,
superior mesenteric vein, and splenic vein thrombosis; extensive ascites; a possible
defect in the right hemidiaphragm; and a large right pleural effusion with associated
collapse of the right lower lobe ([Fig. 1]). There was no pancreatic ductal dilatation to suggest malignancy or obstruction.
Fig. 1 Computed tomography images of the (A) abdomen and (B) chest obtained prior to surgical intervention, demonstrating severe ascites, right
chylothorax, and right lung collapse.
Attempts were first made to drain the chyle that had already collected in his peritoneum
and pleural cavity, and slow the production of chyle. He was admitted to the MGH in
September 2015, where he underwent percutaneous right-sided chest tube placement and
was started on a nonfat clear liquid diet, fat-free total parenteral nutrition (TPN),
and octreotide. Triglyceride levels in the pleural fluid decreased from 244 to 17 mg/dL,
and cytology demonstrated no malignant cells. There was almost complete resolution
of his ascites. His chest tube was removed on the day of discharge. However, though
he continued a low-sodium, nonfat diet supplemented with medium-chain triglycerides
after discharge, the chylothorax and chylous ascites recurred.
In October 2015, he underwent a lymphangiogram, which opacified the cisterna chyli
and demonstrated no evidence of a leak. Several transabdominal attempts were made
to access the cisterna chyli, in addition to attempts to cannulate the thoracic duct,
without success. He was admitted in December 2015 and again underwent chest tube placement,
and was started on a nonfat diet, TPN, and octreotide. Again, there was temporary
improvement, but the ascites and chylothorax recurred soon after discharge.
The hepatology service suggested that his ascites and effusion may be due in part
to cirrhosis and portal hypertension. Transjugular liver biopsy demonstrated no cirrhosis.
In March 2016, he underwent portal vein recanalization and stent placement. The accumulation
of ascites slowed but continued, and he required paracenteses and thoracenteses with
increasing frequency. Repeat axial imaging in August 2016 demonstrated partial in-stent
thrombosis. During this time, he developed increasingly large and uncomfortable bilateral
inguinal hernias and an umbilical hernia, as well as worsening dyspnea due to repeated
reaccumulation of the chylothorax. These symptoms were particularly debilitating given
that the patient was recently widowed and the sole provider for two young twin boys.
His nutritional and functional status began deteriorating, and his overall health
was reaching a point of chronic critical illness, with his serum albumin declining
to 2.5 g/dL.
At this point, the decision was made to attempt repair of the inguinal and umbilical
hernias along with a novel lymphatic cable flap to prevent reaccumulation of chylous
ascites. This flap, proposed by Chen et al, is designed to divert lymph away from
the leak by transferring the superior epigastric vessels with surrounding lymphatic
fatty tissue into the abdominal cavity and anastomosing them to mesenteric vessels,
thereby permitting chyle to drain superiorly through the lymph node chain of the flap
and into the thoracic duct ([Fig. 2]).[4]
Fig. 2 Diagram depicting the lymphatic cable flap, which diverts lymph away from the leak
by transferring the superior epigastric vessels (including the choke vessels connecting
the superior epigastric vessels and deep inferior epigastric vessels) with surrounding
fat and lymphatic tissue into the abdominal cavity and anastomosing them to mesenteric
vessels, thereby permitting chyle to drain superiorly through the lymph node chain
of the flap and into the thoracic duct.
The patient was admitted in January 2017, 1 week prior to scheduled surgery. He underwent
paracentesis with removal of 8.4 L of chylous ascites, along with right chest tube
placement. He was started on a nonfat clear liquid diet, octreotide, and TPN to improve
his nutritional status prior to surgery. He was taken to the operating room and undergone
exploratory laparotomy via a small midline incision, with removal of 6 L of ascites.
No chyle leak was identified, even with a heavy cream challenge the night before and
via orogastric tube in the operating room. Further exploration of the retroperitoneum
was deferred due to the significant inflammatory mass surrounding the pancreas and
extensive venous collaterals from portal venous thrombosis. There was no evidence
of a diaphragmatic defect.
The plastic surgery team performed the lymphatic cable flap. They dissected the right
deep inferior epigastric artery and vein free from the posterior rectus muscle after
lateral exposure of the muscle. Next, they raised the vascularized lymph node flap,
which consisted of the right deep inferior epigastric artery and vein pedicle and
its surrounding fat and lymphatic tissue. The deep inferior epigastric vessels were
ligated distally just before they enter the iliac vessels to obtain length for mobility
of the flap. The flap, which was technically now based on the superior epigastric
vessels as its pedicle (which technically also included the choke vessels connecting
the superior epigastric vessels and deep inferior epigastric vessels), was then swung
medially and cephalad and placed into the abdomen via an opening in the posterior
rectus sheath. The recipient vessels in the mesentery of the ileum were prepared for
microsurgical anastomosis approximately 10 cm proximal to the ileocolic junction.
They then performed microsurgical anastomoses of the artery and vein in standard fashion,
and confirmed patency with Doppler signals. At this point, the right inguinal hernia
was repaired with a mesh plug through the right groin incision made for the lymphatic
flap, and the left inguinal hernia was repaired with a mesh plug through a new left
groin incision. Three peritoneal drains were placed, and the umbilical hernia was
repaired primarily with closure of the midline incision.
The patient tolerated the procedure well, though required aggressive fluid resuscitation.
He recovered in the intensive care unit and quickly weaned off pressor support. He
was advanced to a low-fat diet, and received octreotide and TPN until the day of discharge.
He initially had high serous peritoneal drain output, which decreased with diuretic
therapy. All peritoneal drains and the chest tube were removed prior to discharge
on postoperative day 10. He was started on aspirin 81 mg daily because of the small
vessel anastomoses of the lymphatic cable flap.
One month later the patient was doing well, with no evidence of wound drainage, surgical
site infection, hernia recurrence, or ascites or chylothorax reaccumulation on radiographs.
His nutritional status improved, with serum albumin increasing to 3.1 g/dL 1 year
postoperatively. With over 2 years of follow-up, the patient has continued to do well,
with near complete resolution of ascites and chylothorax, and significant reexpansion
of his right lung ([Fig. 3]). He has not required any further paracentesis or thoracentesis. He has no dietary
restrictions but does continue to take diuretics. He has been very active, working
full-time, and caring for his twin boys.
Fig. 3 Computed tomography images of the (A) abdomen and (B) chest obtained 2 years after surgical intervention, demonstrating resolution of
ascites and chylothorax and expansion of right lung.
Discussion
Chylous ascites is the accumulation of triglyceride-rich fluid in the peritoneum due
to the disruption of the thoracic or intestinal lymphatic system.[1] The causes of this lymphatic disruption are diverse but can be categorized into
three principal mechanisms: (1) obstruction of lymphatics due to fibrotic or infiltrative
processes such as malignancy, leading to exudation of chyle through the walls of dilated
lymphatic channels; (2) lymphatic disruption due to trauma or surgery, causing direct
leakage of chyle through a lymphoperitoneal fistula; and (3) exudation of chyle through
dilated retroperitoneal lymphatics due to congenital lymphangiectasia or thoracic
duct obstruction.[2] In developing countries, the main causes of chylous ascites are infections such
as tuberculosis, while in developed countries the primary causes are malignancy, cirrhosis,
and trauma.[5] The incidence of chylous ascites has been increasing,[6] likely due in part to the performance of increasingly aggressive thoracic, abdominal,
and retroperitoneal operations.[2]
[7]
Pancreatitis is a rare cause of chylous ascites, with less than ten cases reported
in the literature.[8] Chylous ascites likely results from either disruption of retroperitoneal lymphatics
by pancreatic enzymes or from obstruction of lymphatics due to massive peripancreatic
inflammation and eventual fibrosis. When it occurs, chyloperitoneum tends to appear
days to weeks after the diagnosis of pancreatitis,[8] as with our patient.
Chylous ascites is a debilitating condition associated with mortality rates as high
as 43 to 71%, though rates have been reported to be lower in cases of postoperative
chyle leaks.[2] The leakage of chyle prevents the return of protein to the systemic circulation,
leading to severe protein-losing enteropathy and malnutrition. Patients also often
become immunocompromised due to loss of lymphocyte-rich fluid, in addition to developing
hypogammaglobulinemia from protein losses, thus increasing their susceptibility to
infections.[2] Respiratory embarrassment may occur from diaphragmatic dysfunction as ascites builds
and also from chyle accumulation in the pleural spaces, presumably from natural diaphragmatic
channels that may exist.
The management of chylous ascites begins with accurate diagnosis, treatment of the
underlying cause, and preservation of the patient's nutritional status. Diagnosis
of chylous ascites is variably reported as an ascitic triglyceride concentration of
>110 or >200 mg/dL.[1]
[4] Medical management of chylous ascites initially comprises dietary adjustments to
reduce the production of chyle. Patients are placed on a low-fat, high-protein diet
with supplementation of medium-chain triglycerides (which are absorbed directly into
portal venous circulation, bypassing lymphatics).[9]
[10]
In addition to dietary modifications, many patients are started on octreotide or other
somatostatin analogs, which are believed to decrease portal pressure and reduce intestinal
fat absorption.[11]
[12] Other therapies have been suggested, such as glue embolization, surgical ligation,
and embolization of disrupted lymphatic channels; however, data are limited and results
are mixed.[2]
[3]
[5]
[13] Surgical identification and ligation of the source of chyle leak is often unsuccessful
due to extensive inflammatory or fibrotic changes and because patients often have
multiple chyloperitoneal fistulas.[4] Peritoneovenous shunting has been used in the past but is no longer suggested due
to high rates of complications including sepsis, disseminated intravascular coagulation,
and early occlusion due to the high viscosity of chyle.[4]
[14] Unfortunately, one-third of patients with chylous ascites do not respond to medical
therapies.[3] Palliation is achieved by intermittent thoracentesis and paracentesis. Surgical
or chemical pleurodesis may be attempted but may be ineffective or result in loculated
effusions in the setting of massive chyle production, as in our patient.
In this setting, Chen et al harnessed their experience with using vascularized lymph
node flaps for extremity lymphedema, and created a vascularized lymphatic cable flap
based on the superior epigastric vessels and their surrounding fatty, lymphatic-rich
tissue.[4] This flap addresses the underlying lymphatic obstruction by creating an extraperitoneal
bypass of the damaged lymphatics, enabling lymph and chylous ascites to drain via
the superior epigastric vein and surrounding lymphatics in the thoracic wall into
the thoracic duct and subclavian vein. Their operative technique consists of identifying
the deep inferior epigastric vessels on the posterior aspect of the rectus abdominis
muscle, and dissecting the vascular bundle with its surrounding fat and lymphatic
tissue down to the vessels' origin at the external iliac. They next enter the peritoneum,
isolate the fourth jejunal artery and vein, and perform end-to-end anastomoses between
the deep inferior epigastric vessels and the fourth jejunal vessels. They performed
this procedure in three patients with chylous ascites, with resolution of ascites,
thoracic reexpansion, normalized serum albumin, and no perioperative complications.[4]
Our patient is an additional compelling example of the success of a lymphatic cable
flap for cases of intractable chylous ascites. This technique proposed by Chen et
al may be a promising surgical option to offer to patients suffering from this debilitating
condition.[4]
